Metal Casting Vol1
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Metal Casting Basics Vol. 1
DISCLAIMER This information is provided "as is". The author, publishers and marketers of this information disclaim any loss or liability, either directly or indirectly as a consequence of applying the information presented herein, or in regard to the use and application of said information. No guarantee is given, either expressed or implied, in regard to the merchantability, accuracy, or acceptability of the information. Unauthorized duplication or distribution of this material in any form is strictly prohibited. Violators will be prosecuted to the fullest extent of the law. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior written permission from the author/publisher. The author, publisher, and distributor, of this product assume no responsibility for the misuse of this product, or for any injury, damage and/or financial loss sustained to persons or property as a result of using this book. While every effort has been made to ensure reliability of the information within, the liability, negligence or otherwise, or from any use, misuse, or abuse of the operation of any methods, strategies, instructions or ideas contained in the material herein is the sole responsibility of the reader.
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Metal Casting Basics Vol. 1
Table of Contents What Is Casting? .............................................................................. 5 Learn The Casting Process ................................................................ 7 Art Casting ....................................................................................... 9 Aluminum Casting .......................................................................... 12 Brass Casting .................................................................................. 15 Bronze Casting ............................................................................... 17 Casting Associations and Groups .................................................... 19 Casting Furnace Types .................................................................... 21 Casting Jewelry .............................................................................. 24 Casting Molds ................................................................................. 26 Casting Patterns ............................................................................. 28 Casting Sand and Green Sand ......................................................... 30 Casting Supplies ............................................................................. 32 Casting Tools .................................................................................. 34 Casting Torches – Furnace Torches ................................................ 36 Crucibles ........................................................................................ 38 Cupola Casting ................................................................................ 40 Die Casting ..................................................................................... 42 DIY Casting Furnaces ..................................................................... 44 DIY Casting Movement ................................................................... 46 Gravity Casting ............................................................................... 48 Iron Casting ................................................................................... 50 Lost Foam Casting .......................................................................... 52
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Metal Casting Basics Vol. 1 Lost Wax Casting ............................................................................ 54 Resin Casting .................................................................................. 56
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Metal Casting Basics Vol. 1
What Is Casting? Metal casting is an ancient technique that has a variety of applications and purposes. Civilizations from the dawn of time to present day have used metal working as a way of creating artistic, religious, and practical items. The process of metal casting involves melting metals at high temperatures and using molds to then shape the metal into new items. The furnaces used in metal casting helped pave the way for the Industrial Revolution, without which the course of history would be dramatically different. Metal casting is just one form of metal working that has seen a recent surge in popularity as resources are becoming more affordable and communities are springing up to share information, ideas, and projects. Metal casting requires specialized equipment, knowledge, and some creativity. While metal casting is used on an Industrial level as the process cuts cost and proves to be highly efficient, many individuals participate in metal casting as a hobby and in artistic endeavors. Many people are drawn to metal casting for one reason or another, although there seems to be two main motivations that stand out. The first motivation that brings hobbyists to practice metal casting is need; people may need to create items or parts for other ventures. Metal casting is a great way to build hard to find pieces for models, restoration projects, and even just small replacement parts needed for common household items. The second motivation for using metal casting is using it as a way to create sculptures or other artistic endeavors. Whatever the reason, small scale metal casting is attractive because that it can be done right at home, either in the backyard or workshop. Individuals working in metal casting are able to create home made tools and equipment like furnaces and molds. Metal casting is only limited by the individual’s desire, so for those with the time and the need, virtually anything is possible. The actual casting process in metal casting has several forms, the most popular
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Metal Casting Basics Vol. 1 being sand casting. Sand casting involves creating a mold from sand which can be created at home, and then pouring the liquid metal into the mold. Afterwards, the metal is allowed to air dry and the mold is removed. This type of casting proves to be the most economical, but other types of casting can provide fuller detail and higher quality results. Since metal casting involves working with metal in its molten form, the process can be dangerous if undertaken by the reckless or ill informed. The melting points of several metals are well above 1,000 degrees Fahrenheit, or 530 degrees Celsius. It is vital that anyone wanting to work with metal casting take all the proper precautions. Safety advice can range from simple common sense such as "never look directly into a high powered flame" to more specific warnings such as "when molten metal contacts a nonporous surface with water it is liable to explode, splashing hot metal everywhere." The use of appropriate safety gear such as gloves and goggles is necessary as well. With time, dedication, and some know how, anyone can practice the craft of metal casting. Metal Casting is a very enjoyable and rewarding craft but it does require a certain amount of education to get started.
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Metal Casting Basics Vol. 1
Learn The Casting Process Metal Casting presents a great opportunity for artists and hobbyist as it gives them a certain amount of control and creative license with regards to the end result. Metal Casting is an ancient practice that is still used to this day in industries such as manufacturing airplane components to small scale hobby casting. The casting process which is so crucial to the entire form is where one takes melted metal and creates an object based on a pattern by using a mold. On first glance the entire casting process seems complicated and even convoluted but with a little patience and time, most of which will be spent reading, the process involved in metal casting can be understood and even mastered. Metal casting does take technical know how and skill. Luckily, you do not have to be born with a golden furnace to cast. This means that if you have the will, not to mention the mold and the furnace and all the other tools, you have the way. Since each casting method differs slightly from the other, it is advised to read up on it before you try your hand at the technique. The most common casting method is sand casting which is probably the best way to start out a metal casting career. What I will attempt to do is to provide a general overview of the basics in metal casting. The specifics for each casting process will differ of course since, for example, Investment casting uses wax and not sand and die casting uses centrifugal force where most other casting processes do not. So, it will be important to research the process involved with each individual casting type but it is always great to have a base to build from. The casting process for most forms will include making the pattern, making the core, if one is needed, molding and the actual melting of the metal, pouring, and then finishing it all off by cleaning.
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Metal Casting Basics Vol. 1 Pattern making is the first step in any casting process. You will have to first determine what is needed for your project. The pattern is considered the original and can be any needed shape from a bolt to a figure of a horse. If the object being made is hallow or has parts with holes or other empty spaces, you will need to make a core. The core is inserted into the mold so that the casting can take the appropriate shape and that metal does not fill in areas that should be left empty. The core is collapsible so it can be removed after the casting process without any damage to the finished product. The molding contains the flask which is created by an upper half or the cope and the lower half which is the drag. In the sand casting process, sand is packed into the molding where the pattern is placed. Once the sand is rammed or packed the pattern is removed then preparations can be made for pouring.
Depending upon the kind of metal and the type of furnace the melting step will vary. The Crucible is what the metal is melted in and the Crucible handling tools will allow you to safely move the crucible to the mold where you will pour the molten metal. You will allow the metal to solidify, and then remove the mold very carefully. During cleaning you will be removing any excess bits and pieces on the finished product and in essence, make it nice and clean, and ready for whatever intended purpose you had in mind. The casting process is a lengthy one involving many steps, beyond the general ones stated here. For this purpose it will be important for you to do some reading and some research so that your attempts at casting will come out just as you would like.
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Art Casting Art casting is an ancient method of creating statues and sculptures that has been in practice in Meso-America, China, and Ancient Egypt since 2000 BC. The Greeks practiced it, so did the Romans, and pretty much any civilization with a strong interest in art. Bronze is an alloy of tin and copper that has been used to make weapons and sculptures since its discovery by man. Bronze is able to fill in the fine detail of molds making it very desirable to artists. When art casting, bronze is the alloy of choice since it is both beautiful and easy to work with. There are few examples of bronze statues left from antiquity since the alloy became scarce and many of the statues were melted down for weapons and other sculptures usually for new emperors or victors. The Lost Wax Casting process is the preferred method used when art casting. This process was used in ancient times to create bronze items. Small foundries like the type found in backyards, personnel workshops, and garages are able to use the Lost Wax Casting process with a certain amount of professionalism. Commercial foundries and professional art companies use the Lost Wax Casting process as well to create custom items and monuments. The process remains, essentially, the same since the ancient craftsmen who first pioneered the method. When used in commercial manufacturing or jewelry making, the Lost Wax Casting process is called Investment Casting. Art casting is one of the more enjoyable reasons to fire up the furnace and get into metal casting. While most think metal casting to be strictly limited to hobbyist and historical re-enactors, casting is a popular skill and craft used by a wide range of people for varying reasons. Artists see the need to have metal casting skills as it allows the artists to have direct control over the process instead of out sourcing it to a commercial foundry. Commercial foundries that specialize in custom pieces will
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Metal Casting Basics Vol. 1 often charge outrageous prices for their services. Art casting on your own is often times economical and just smart. The Lost Wax Casting process is rather simple when compared to other casting methods but it can be time consuming and attention to detail is important. The artists will start with an original piece sculpted from wax. The original can be made of other substances like clay or even metal but wax seems to be the easiest to work with. The original will be used to make the mold. If the piece to be cast is large, multiple molds will be needed. This is common in art casting and completely possible with the use of shims and keys that will allow placing the pieces together after the casting process easier. Most molds will be made out of latex or other materials to help transfer the fine detail into the mold cavity. The original is often destroyed during the mold making process upon removal. Molten wax is poured into the mold until the desired thickness is achieved. When dry, this wax copy is removed and chased which rids the piece of imperfections and is used to combine the pieces. You will place paths for the molten metal on the wax copy. You will also place a cup or funnel at the top of the copy. This process is called spruing and is done in wax. A ceramic shell is placed around the copy. The shell isn't really ceramic but a sand and liquid silica combination. You will repeat this step until the shell is thick enough for the piece. You will then heat the item which will melt the wax inside. The wax runs out of the shell through the paths placed during spruing. Then comes the part for the molten bronze. The bronze is poured into the top of the hollow shell. When cool you are going to remove the shell carefully to reveal the finished product. The bronze sculpture is chased, painted, and finished up however the artists choose. Art casting can be done with any metal or alloy. If you are going to use the Lost Wax Casting process then you do not have to stick with bronze. Try other metals
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Metal Casting Basics Vol. 1 until you receive the perfect look for your piece.
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Aluminum Casting Aluminum is the most common alloy used in metal casting. There are several reasons for this, but the main one seems to be availability and quality. Many metal casters have access to a large amount of aluminum with soda and beer cans that they crush and melt down. Aluminum has several desirable properties for the metal caster no matter if they are a hobbyist, artist, or are casting needed parts for home repairs. Many who cast aluminum also love the alloy since it can be used in all of the varying casting processes giving it a wide range of possibilities. Aluminum is often used as a practice alloy for the first time metal caster or for casters who are trying out new methods and ideas. Many of the small home furnaces that are found in most hobbyists’ foundries will be able to easily melt aluminum. It may even be possible to use charcoal though many just use propane since they have it on hand for other alloys. For your first run at casting, charcoal should be fine. If you do choose to use soda cans for your source of aluminum you are going to need a fair amount depending on the size of the item to be cast. Make sure to crush the cans as much as possible before placing in the crucible or other area that will be used to melt the alloy. Since any metal casting process can be used with aluminum the choice will rest with you. There are three casting methods out of the numerous methods available for aluminum that seems to be preferred by small time metal casters. These methods are sand casting, lost foam casting, and investment casting. Remember, though, aluminum can be used with any metal casting process so do not be afraid to experiment. Sand Casting
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Sand casting aluminum is very common and is a popular way to break in a new furnace. Casters use sand mixed with a bonding agent to create a mold around the item to be cast. The item, or pattern, is removed very carefully revealing the mold. If there will be any empty spaces in the finished product then a core is added to the mold. The core can be made of sand and is placed so that the molten metal fills the area of the mold around it. So, say you're making a picture frame you will place a cone where the glass will go so the molten aluminum will not fill that area. Many choose not to use sand casting since it does not allow for fine detail whereas other casting does, but it is inexpensive. Lost Foam Casting Lost foam casting which is sometimes called evaporative casting. The lost foam casting is a form of sand casting. The entire process is relatively cheap and when used with old soda cans casting aluminum this way is great on the budget. A foam copy of what you want to cast is created and surrounded by a ceramic shell. You will place the copy in loose sand which will help to hold the shape during the pouring process. The molten aluminum is poured into a cup that in inserted into the copy. The foam vaporizes and the aluminum replaces it filling the area in the ceramic shell. Removing the shell will reveal the aluminum casting. This method is great for fine details but the copy is lost to the ages. Luckily, foam is not all that expensive. Investment Casting Investment casting is commonly used by jewelers as it allows precise castings with full detail. This form of casting has been around since ancient times under the name of lost wax casting. Investment casting involves creating a wax copy which is then covered in slurry creating a shell, much like the kind of shell in lost foam casting. The molten aluminum replaces the wax which melts out of the shell and can be
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Metal Casting Basics Vol. 1 collected for reuse. Artists and casters that need high precision parts favor this technique. Given the number of options that aluminum presents to the caster finding the right casting method will involve some time. To help decide which aluminum casting process is best consider factors like quality and cost. Many metal casters use aluminum far more then they use other alloys like brass, bronze, or iron.
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Brass Casting Brass is a great metal to cast with as it can provide some really great looking results. Many believe that brass, an alloy of zinc and copper, has been around since our prehistoric ancestors. Today brass is used for a multitude of products from coins to trumpets not to mention a whole bunch of other musical instruments. The low melting point makes brass a really great material for metal casting since even the smaller home grown furnaces can be used. By adding and subtracting alloys from bronze one can successfully make hard or soft bronzes. Aluminum and tin are sometimes added to bronze to create a layer that is not corrosive and very durable. Of course, for the home foundry users, playing alchemist isn't really an option or necessary and scrap brass is perfectly acceptable in many cases. Locating scrap pieces of brass should be sufficient enough for whatever project you have in mind. Due to brass' gleam and yellow shine, many artists will use the alloy for sculptures, jewelry, and other decorative items. Other metal casters may choose to use brass for general hardware needs or vintage car restoration, and of course, whatever else they may choose. Generally there are three casting methods that prove to be suitable for brass casting. Metal casters may choose to experiment with different methods and should not allow themselves to be limited. Lost Wax casting is usually associated with bronze casting but can also be used for brass and for really any other metal. By using a wax model and covering it with a ceramic shell, artisans are able to inject the molten alloy which replaces the wax. Chipping away the shell will reveal the brass piece. Lost wax casting is used when a high attention to detail is needed. Artists or metal casters looking to create decorative brass pieces or sculptures will find that the lost wax casting technique will meet their needs far better than other techniques and methods.
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Metal Casting Basics Vol. 1 Die casting is yet another method used for brass casting. Die casting is normally used in commercial foundries since the initial start up cost is undesirable for the smaller home foundries. By using a reusable mold created from steel, the caster will be able to create scores of identical products. Die casting with brass should be used if the caster or artists is planning to make multiples of one product and can find a viable market for those pieces. Sand casting is probably the oldest type of casting and is still a popular method especially for small foundries. The brass is poured into sand molds and can create a unique look which may be preferred for the artisans. Sand casting tends to be the most economically sensible for small foundries and if the casting does not have to be incredibly attractive then this method is preferable for many. Whichever casting method is used for casting the brass really depends on the individual. Many find that casting brass to be fun and easy since it does melt rather easily. A large expensive furnace is not a requirement when casting brass so first timers using small home made furnaces will find this alloy attractive. Many have even been able to melt brass in small ceramic pots using charcoal! Some ideas of what to make with brass include candle holders, plumbing fixtures, and even musical instruments
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Bronze Casting Bronze Casting has been practiced for centuries. Many civilizations have used this alloy for weapons, sculptures, and general pieces of hardware. The popular way to cast bronze is the Lost Wax Casting process which was first used sometime in the 3000 BC near ancient Sumeria. The Lost Wax process is still used to this day and its modern equivalent Investment Casting is very popular with jewelry makers. Bronze is the preferred alloy for metal working artists as it's relatively easy to work with and resistant to corrosion. The properties of bronze tend to be stronger than most other alloys, except of course for steel, and lends itself easily to the molding and casting process. Many small foundries like the kind that can be found in a backyard or workshop find that bronze is a great material to work with and with a melting point of 1,700 Fahrenheit or about 925 Celsius many homemade furnaces are able to melt down the bronze quickly and efficiently. Many modern day artists create their own furnaces with the metal casting in mind. These metal casters employ the Lost Wax Casting method which proves to be the best when dealing with the alloy. The Lost Wax Casting is making an original of the sculpture from wax and then creating a mold using this original. Often times the original is lost during the mold making process so keep that in mind if you want to hang on to the original for whatever reason. Molten wax is poured into the mold which is chased or smoothed of imperfections. During this point, any other pieces are attached and small wax tubes are placed into the piece. These tubes will be how the molten bronze is going to travel into the piece replacing wax with the alloy. When this is complete the artist will create a ceramic shell around the wax model. This shell will help form the molten bronze which will melt the wax. When the molten bronze is poured the bronze takes place of the wax. Afterwards, the artist will crack the shell and reveal the bronze piece. This method allows the transfer of very exact detail from the wax to the bronze.
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Metal Casting Basics Vol. 1 Patina is added to the figure at the artist's discretion. The Patina is a chemical that when applied to bronze creates colors and makes the bronze take an aged look. The Patrina compounds used depends on the type of color desired. Ferric Nitrate will make the bronze take on a red or brown color while Sulphurated Potash will make black and Cupric Nitrate will create blue and green. Modern day artists choose to go with a very high polished bronze instead of using these compounds. This step depends solely on the artist’s taste and the look they are going for. Bronze casting will remain a popular medium until another alloy is developed that exhibits properties that are easier to manage and are more resistant to corrosion. Casting the alloy is easily done so metal casters that want to experiment are encouraged to do so. Making anything from small figurines, large sculptures, and even cabinet handles can be accomplished with the use of bronze. The only limitations in bronze casting are with the caster himself.
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Casting Associations and Groups Metal casting has endured through the ages since the time of Ancient Egypt, possibly longer. Since then small foundries have developed to meet the needs of the individual caster. There are several reasons that people choose to create their own home grown foundries. A top reason is the need to create parts and pieces that are no longer available on the market or that are just too expensive to purchase. Those who get into metal casting for this reason are usually interested in restoration projects, home improvement projects, or hobby building like model planes and trains. Artists are the other group that see metal casting as a cheap and easy way to create sculptures from small to large. Jewelers even use metal casting to create complex pieces that would just otherwise be impossible to create. Given the wide scope of metal casting there are several methods and techniques that have developed. For those new to metal casting or for those wanting to try some of these other methods may find it difficult to find information on your own. Luckily, there are several metal casting associations and groups that are more then willing to share information and exchange ideas, projects, and pictures of the goings on in the their home foundries. On the internet, metal casting associations and groups are either message boards full of casters where they can ask questions, post ideas, and pictures or are websites that are maintained by a set group of people offering general information and educational resources. Both of these types of websites are incredibly helpful to metal casters who can benefit from the educational purposes of some of the sites tempered with the real life applications and experiences of the message boards. There will be more industrial foundry and metal casting information than sites directed at the small home foundries. Industrial metal casting sites can be
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Metal Casting Basics Vol. 1 wonderful sources of information so do not skip by these. Use both small metal casting sites and industrial sites to your advantage. One of the most popular message board type sites for information is the Casting Hobby Group found through Yahoo Groups. This casting group was developed and maintained by experienced metal casters and enjoys a high amount of activity. This is a great place to go to for quick information and ideas not to mention photos and even furnace building plans. The Casting Hobby Group can be found at http://groups.yahoo.com/group/castinghobby/ The Association of Backyard Metal Casters is located at http://www.abymc.com/. This online metal casting association has an extensive membership complete with informative articles, forums, and even live chat. Of course, pictures are posted on the site to give visitors ideas about what other furnaces and foundries look like. Don't worry if you're foundry isn't pretty, there actually doesn't seem to be very many of them that are. Now, The American Foundry Society is mainly for the industrial metal casters and companies but they also promote information and education to consumers. The information provided on the site is great for anyone wishing to follow advancements in metal casting technology. There is even an online store. http://www.afsinc.org/ is the online home for the American Foundry Society. For the most part metal casting associations and groups exist on the local level more than a unifying force on the web. What does exist on the web is a great source of information, ideas, and insight. It is a great idea to join any of the groups you can in order to share and find knowledge.
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Casting Furnace Types In Metal Casting, the type of furnace you have at your foundry, or workshop determines a lot of the work you can or can not do. Many metal casters enjoy making their own furnaces and have done so quite successfully. The plans for home made furnaces are eagerly shared among the enthusiasts so finding blueprints and instructions should not be difficult. But before you rush off to find the blueprints you may want to take time to learn about the types of casting furnaces available to help determine which one will suit your needs. This is not saying that you should only have one furnace at any given time, but this way you will know what project will work best for which furnace. Cupola Cupola furnaces are among the most popular with backyard foundries. Many casters construct their own cupola which proves to be cost effective and highly efficient if done properly. Since cupola furnaces can achieve high melting temperatures they are primarily used for the melting of iron and bronze, though aluminum can also be melted when attention is paid to keeping the temperature low. The primary fuel source for cupola furnaces are coke using limestone for flux. By not using a crucible, the Cupola furnace is able to melt the metal at a faster rate. While individual designs of these furnaces differ due to varying resources and design ideas, the basic component of a cupola furnace is the same. The cupola furnace must be elevated above the ground and installed with a drop bottom usually hinged, which will allow the excess metal, fuel source, and other waste to drop from the furnace. The tap hole and shaft which will allow the molten metal to flow from the furnace and into the ladle and air shafts are also required. A slag tap hole can be placed on the furnace usually in the back, higher then the tap hole, which will allow the slag to flow out easily.
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Metal Casting Basics Vol. 1 With most small home foundries, the cupola furnaces are preferred over that of other furnaces for its high melting rates and for how easily the construction of such a furnace can be. Reverberatory The Reverberatory Furnaces are commonly found in industrial plants but there have been quite a number of home grown foundries that have used this furnace type with much success. The basic idea of a Reverbeatory Furnace is to use the heat reflecting off a surface, usually brick, to heat the metal, which is aluminum in most cases. This way, the metal does not come into contact with the fuel or the flame. This process is also used in Puddling Furnaces. The name Reverberatory and Puddling are often used interchangeably. By placing the metal in a shallow depression and then directing an intense flame over that depression and to the wall, the heat rebounds to melt the metal. Many casters will adjust the length of the flame since a longer path will mean that the heat will be more intense. There are many designs for the reverberatory furnace, all of which will include exhaust ports and the rear of the furnace must be able to withstand the intense heat and be able to bounce it back into the chamber. Bronze, aluminum, tin, and many other ores can be melted in a reverberatory furnace all depending on the construction of the actual furnace and the heat of the flame. This type of furnace has been around since at least the Middle Ages and was used primarily for bronze work. Electric Arc Electric Arc furnaces are normally used in Industrial foundries. Most hobby casters do not use these furnaces due to cost, space issues, and a general inconvenience. There are two forms of the electric arc furnace, the direct and indirect.
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Metal Casting Basics Vol. 1 The direct arc has three electrodes which are used to heat metal by way of the arc. This creates an incredible amount of heat and so water jackets and other cooling devices will be needed for operation. The indirect arc just uses one electrode and works in much the same way as the direct arc furnace. Electric Induction Electric Induction furnaces are becoming all the more popular with large industrial size foundries that enjoy the clean burning and efficiency of an electrical furnace. Copper coils surround the crucible with the metal inside which can reach extremely high temperature suitable for melting most metals. Rotary The Rotary style furnaces are hailed for their ease of use being fully or at the very least partially automatic. These furnaces tend to be harder to construct though there are resources and companies online that sell rotary furnace. The different furnace types do affect the quality of the work being produced, so it is important to keep that in mind as you cast. With a little trial and error, you should find the perfect furnace to fit your needs so you can start building one of your very own.
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Casting Jewelry Casting Jewelry is an ancient skill that has been around for as long as there has been jewelry in the world. The Ancient Egyptians are usually credited with perfecting the process but casting jewelry was also practiced by meso American societies and cultures located in Asia and the Middle East. The casting process is called Lost-wax and is still very popular with craftsmen who enjoy making hand made jewelry. By the name of the process, one can guess that wax is involved of which will be lost. While the Lost-wax process is mainly used for the casting of rings and bracelets, other items such as sculptures can also be created. Investment casting is another name of this casting jewelry method and both are acceptable terms it just depends on the speaker's preference. The Lost-wax casting process has many benefits. When making jewelry this way, the caster will be able to make identical pieces quickly and efficiently. There are several companies and individuals willing to cast the piece for you for a price. Many of these companies may overcharge, the cost of commerce, so if you have the resources and ability you might be better of casting your own jewelry. Lost-wax casting involves a number of steps. If followed properly and with precision the artist will find the process enjoyable. Before you begin, you will need to come up with an idea for the piece of jewelry. Generally, the sculpture of the piece is created using wax though some prefer having a metal master copy in case of mistakes. You are going to create the mold using the original. The molds used for casting jewelry allow a great amount of detail. When the mold is finished, you are going to fill it with wax to create a wax copy which will then be coated with sand and silica. This ceramic shell will then be heated so that the wax is melted out. The wax can be reused so make sure to safely collect it during this step. The ceramic
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Metal Casting Basics Vol. 1 copy will be hollow and you will have to test it for holes before pouring the molten metal. Afterwards, you will lightly hammer the ceramic shell away to reveal the finished product. The end result of the Lost-wax process is usually very detailed and exact creating a beautiful piece. Casting jewelry can be a profitable business depending upon your skill level and creativity. This skill is diminishing as the jewelry companies switch to computerized and automatic means of creating their pieces. While this move is smart for the jewelry business as it reduces the production cost, the end result lacks a certain desirable element that hand made jewelry posses. Casters will be able to use the mold created during the Lost-wax process a few times before a new mold has to be made. Extra care and attention has to be paid to polishing any imperfections or patching any variants during the casting process. Several things can go wrong during casting especially when you remove the mold so take care to be extra careful and attentive during this time. Casting jewelry is a valuable skill to master and if you plan on making any money from your home foundry, this is a good place to start.
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Casting Molds Casting molds are an essential part of the metal casting process as it will be used to shape the final result. Nearly all metal casting methods will use some type of mold. The standard mold will consist of a cope and drag that when together is called a flask. The mold itself can be constructed of several materials depending upon the casting method. Most molds will be made from latex, fiberglass, sand, and even metal. Sand molds are the most popular since Sand Casting is commonly used in small home foundries. In Permanent Mold Casting, the mold is created from metal. Most molds can be used over and over again, but not all of them. Certainly the metal molds can be used multiple times without loosing any quality from the finished product. However, molds created using sand or other materials will not have a very long shelf life. This is not generally seen as a huge problem just a minor annoyance since mold making is relatively cheap and easy. No matter what material the mold is made from, the basic construction is pretty much the same. The molding box is called the flask which has a cope, the top, and drag, the bottom. You will then fill the flask with the molding material and then place the original into the mold. So, if you want to cast a tiny metal elephant, you will place an original of the elephant usually made from clay, wax, wood, or even metal into the drag of the flask. If this is done in sand you will ram the flask until the sand is packed tightly around the original. The top of the flask, the cope is then placed on and more molding material poured in. The entire flask is then rammed or vibrated making sure everything is packed in nice and tight. When the molding material is dry, you will remove the flask and carefully split the mold to retrieve the original, in this case the tiny elephant. Now, if you want to make sure that there are some empty spaces in the cast to be finished then you will place cores into the mold. The cores are made of sand or wax.
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The type of mold used depends heavily on the type of casting, alloy, and complexity of the pattern to be cast. Metal molds have little use in small foundries unless you plan on casting a lot of tiny metal elephants. In some cases, pre-made molds can be found in hobby shops or through company casting companies. Usually, pre-made molds are used in miniature castings. Many individual metal casters prefer to make their own molds since it is inexpensive and allows them greater control over the finished casting. Metal casting involves several sets of skills and mold making is one of these skills. Mold making is an invaluable skill for metal casters as it is so very important to the casting process. Not only are molds used in metal casting but in other casting types as well. Resin casting and other plastic casting requires a mold as well. The flask can be made of wood, metal, and in some cases those toy building blocks, we all know the type. As long as the flask can hold the mold material until it dries it can be used. Every metal caster should learn how to make a mold instead of relying on others. It's not only about independence but about saving money as well. Making your own mold is just cheaper.
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Casting Patterns Metal casting is a useful skill that has its roots in antiquity. Weapons and sculptures were traditionally created using this method but as the DIY movement gained momentum many modern day casters have found a use for metal casting to make plumbing fixtures, door knobs, and many other items. Today, small foundries can be found in many backyards, garages, and workshops. In order to make a casting of metal, you will need a furnace capable of melting metal alloys at high temperatures. Usually, individual metal casters will construct their own furnace. There are companies that will sell small scale furnaces but they are often costly. The most common type of casting is called Sand Casting which uses sand or green sand to make the molds where the molten metal will be poured into to form the finished product. The mold is a handmade item placed in a flask which has two parts, a cope and drag. The mold is usually made of sand, but can also be created using other ingredients like latex or even metal. It is in the mold that you will set the pattern to form the mold cavity. The mold cavity will be an impression of the pattern including the fine details which will then be filled with the molten alloy. Pattern casting is an art form in itself, really, but anyone can create a pattern even if you have no artistic skill what so ever. The pattern is an original which will be cast into metal. Common pattern castings include complex engine parts for models, replicas of Civil War era weapons, sculptures, and even jewelry. The pattern can be made of any material like clay, wood, and wax. The pattern material really depends on a few factors like the casting method and the availability of the material. If you are able to carve wood then you can use this skill to make patterns. There are some casting methods that call for the patterns to be made of certain materials. An example of this is the Lost Wax Casting Method which will use wax as the pattern.
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When creating the mold, you will place the original into the drag of the flask and place more molding material on top forming the cope. When the mold is dry you will carefully remove the pattern revealing an impression in the mold. If you are creating your own pattern you will need to make it with Contraction allowances in mind. This contraction allowance will compensate for the shrinkage that occurs in many casting processes. In order to take out the pattern without disturbing the mold, draft allowances need to be considered as well. The pattern should have tapered edges to allow for easy removal. Many who make their own patterns will add sprues, gates, and risers to the pattern so that when castled these items will already be in the mold. These devices will allow the molten metal to find its way into the mold cavity. If you find it difficult to make your own patterns then you can pay for pattern making services; although many casters in the same situation will just learn how to make patterns to save money. Pattern casting is a valuable skill to have and can be learned rather easily.
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Casting Sand and Green Sand Sand casting is the most ancient form of metal casting and has been around since at least Ancient Egypt. Many metal casters prefer using sand casting over many of the other forms of processes because it’s cheap and the sand used is readily available. Many experienced metal casters will continue to use sand casting even though their abilities and resources allow them to use the other metal casting methods like Lost Wax Casting or Investment Casting. Sand casting involves less material and less effort than the other casting methods. Sand casting is a great way for new casters to get into the trade. In sand casting, the metal caster will create a mold by placing an original in the flask which is filled with sand. The original will be a pattern of what you want to cast. By ramming or vibrating the sand, the caster creates a mold of the original. The casting sand used needs to be able to retain the shape of the mold. Finding the right mixture of sand to water is crucial. Too much water can ruin the mold and possibly destroy it while too little water will create a poor casting. Green sand is a type of casting sand that many prefer since its ability to retain the shape of the mold is far better then normal sand. Green sand usually contains bentonite clay, sand, and water. After the sand is packed, the pattern or original is removed carefully. Molten metal is poured into the mold and allowed to cool. The metal caster will then break the mold and dig out the casting. While sand casting has its benefits the use of green sand can greatly increase the likelihood of a successful casting. Green sand is not really green the color refers to the damp nature of the sand. Green sand is created by adding water and bentonite to the sand. One of the benefits of using bentonite in green sand is that it makes
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Metal Casting Basics Vol. 1 the sand more permeable which allows more gas to escape. Metal casters can get the bentonite from a variety of sources like home improvement stores and even from household resources. Many have milled the type of cat litter that clumps since one of the ingredients is bentonite. Remember to work in a well ventilated room or to wear proper face gear when working with bentonite since it will irritate the lungs. There are several recipes online for green sand but the most common method is experimentation. What you are looking for when mixing the sand, water, and bentonite is a texture that is not wet but damp and will retain its shape when molded. The type of sand you use to make green sand depends on you and the availability of the sand. Many will use sand that they found out in the wilds of nature and some will buy bags of sand like playground sand. As you cast with green sand you will find out which works best with what metals. Green sand is growing in popularity as more casters are recognizing the properties of this method. If you have traditionally used regular sand casting, green sand casting will prove to be easier to work with and will produce better casts. The best part about green sand casting is that is does not cost a lot of green.
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Casting Supplies Metal casting supplies can run the gamut of cheap to expensive. Home foundries tend to use supplies that are not too costly or that can be found close at hand. After all, home metal casting is usually a hobby and many get into this hobby since they need a cheaper source of parts and pieces that are either far too expensive or just impossible to find. This reason is actually what draws many people to metal casting in the first place. Given this, metal casting supplies used in smaller backyard foundries are generally cheap and made of items that are available in the garage or can be found at home improvement stores. There are several online resources and stores that offer supplies specially made for metal casting and if you have the money and are unable to create your own, it is encouraged that you purchase already made supplies. The metal casting supplies you will need ultimately depend upon the type of work you plan to do. If you plan to use lost foam casting you will not need any wax and in that same thought you won't need any foam if you are going to use lost wax casting. The furnace type is also a consideration. Cupola furnaces do not use crucibles. A crucible is where you place the metal which will then pool and collect inside. So it is important to decide what kind of casting process and what kind of furnace that will be used before you rush out to buy supplies. As for the supplies this will include the fuel source. Fuels sources can range from wood to propane. Metals with a higher melting point will need propane while wood can be used to melt pewter and possibly aluminum. Most home foundries will use propane since it produces a high temperature and is easily available. Many of the metal casting processes use sand as a way to create molds and help secure those molds during the pouring. The type of sand used does not have to necessarily be specially formulated. Sand has been used in casting since ancient times so it only makes sense that most sand types can be used. Many hobbyists will
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Metal Casting Basics Vol. 1 even use playground sand to meet their needs. Now, there is a special type of sand used in casting called green sand. Green sand packs well and is able to hold its shape far better then common sand. For processes like lost wax you will need to find a healthy supply of wax since many of the steps involve the creation of wax models and molds. The good thing about this process is that the wax can be reused time and time again. Supplies for lost foam can be found in home improvement stores since foam insulation is suitable to use. You will not be able to reuse the foam but luckily, the foam is cheap. Perhaps the most important casting supply is the metal itself. The metal used in casting varies due to need. Aluminum is a common alloy used in casting for a number of reasons, chief among them is availability. Aluminum soda cans are crushed and melted and proves to a good source of the metal. Many casters will find scrap metal in junk yards which tend to be a good source for brass, bronze, and iron. There are places to buy metals in ingots if you want a purer metal to work with. Metal casting supplies often dictate what the caster can and can not do. Keep this in mind as you plan your next project as adjustments might be needed to your plan.
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Casting Tools Metal casting takes a certain amount of skill and knowledge not to mention the appropriate tools of the trade. Luckily, anyone can learn metal casting and the tools are widely available and some can even be crafted right at the home workshop. Most of the metal casting tools are pretty standard and can be used for the different casting processes. If you already familiar with metal work then the chances are pretty good that you already have some of the tools in your garage or workshop. In fact, it is possible to make many of the tools that are commonly found in small foundries. If you are unable to make your own tools then there are many online resources where you can buy tools and even home improvement stores will have the tools. The absolute must have metal casting tools will be used for safety. Safety in the home foundry is a must since any accidents that can occur will more then likely result in devastating injuries, remember safety first. Gloves will be necessary when pouring the molten metal or picking up the crucible with the aid of heavy strength tongs. The heat from many of the molten metals will be very intense so long sleeve shirts are also advisable. Jeans and work boots will help prevent any injuries in case of spills. Remember, molten metal will splatter when poured on wet surfaces or surfaces that have recently been wet. Even concrete can cause molten metal to splatter that is why metal casters always keep a muffin tin on hand where any excess molten metal can be safely stored. Always wear goggles when working with intense flames to avoid eye damage. Without the appropriate safety gear injuries are pretty much guaranteed. The furnace is the most important tool of the trade when it comes to metal casting. This tool does not necessarily have to be large and can even be as small as a flower pot. Size does not matter and even the smallest of furnaces can melt your alloy.
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Metal Casting Basics Vol. 1 The individual tools used in the furnace can differ. Not all of them will use a crucible but all of them will use a fuel source and require a refractory of some sort to help shield the furnace and direct the heat. The crucible is where you place the metal to be melted. It pools inside the crucible and with help of tongs which can be made in a workshop is transported to the mold to be poured. For furnaces that do not use crucibles like cupolas, a ladle is needed to transport the mold. The mold is what will be used to shape the molten metal into the desired piece. The mold consists of two pieces a cope and drag. The cope is the top half of the mold and the drag the bottom. The sprue is where the molten metal enters the mold. After the metal solidifies the sprue is cut away from the cast. Metal casting involves many other tools some of which are used for all processes and some are not. The tools needed change from job to job. When you start out in metal casting make sure you gather all the needed tools before you begin. From there you can easily increase your tool inventory as you take on new jobs.
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Casting Torches – Furnace Torches Metal Casting provides the hobbyist with a great way to create personalized parts and pieces that may otherwise be unattainable or far too expensive. Casting is an ancient art that is still is use to this day by major industries to artists to those with backyard foundries. This skill is a valuable one that promises to provide the hobbyist with a rewarding past time. Most hobbyists begin their casting careers with a modest sized furnace to fit their most basic needs. Within a few months, the hobbyist might find that the furnace has grown and that they are casting at every chance that comes along. Don't worry, this is completely natural. To say that metal casting is addictive is an understatement. Metal casting provides a way for an idea to materialize through molten metal. This is perhaps one of the greatest parts of the entire metal casting process like seeing what was once just sketches solidify from liquid iron, or whatever metal is used. All the metal caster needs is an idea and red hot liquid metal. The furnace is the pride and joy for the metal caster. Most will construct their own furnace tweaking the design here and there to better suit their needs. Many home foundries are based on home made furnaces and if constructed correctly can prove to be highly effective. The crucial part of the furnace is the furnace torch. The torch brings the heat, incredibly high heat, and without it that chunk of metal would just sit in the crucible and never see life as something new and exciting. Except as a paper weight; a very ugly paper weight. When searching for an appropriate casting torch the hobbyist will need to take several things into consideration. The size of the furnace, and what metals you plan to use are chief among the considerations. Many casters will use a torch that uses propane gas as it provides enough pressure and heat to melt most metals. If the hobbyist plans to use natural gas like the kind that is provide in households they may find that the pressure is just not enough and the desired temperatures will not
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Metal Casting Basics Vol. 1 be reached. The same is true for Butane. While natural gas and Butane can be used, propane seems to yield the best results. Oxyacetylene torches are a favorite with many casters especially for casting iron. Price is yet another consideration. While it may be possible to rig a casting furnace it is not always advisable. Torches can range in price from $40 to several hundreds of dollars depending upon the size, the use, and accessories. Many jewelers are able to use small independent casting torches but when dealing with metal casting in furnaces you will need to use a torch that can be mounted and used in such a fashion. Many think that just because you need a furnace torch you are going to need a large furnace. This is simply not true. A small furnace and furnace torch can produce enough heat to melt aluminum, iron, and a number of other metals. One of the furnaces functions is to help the flame reach optimum temperature and in the case of Reverberatory Furnaces, a furnace torch is an absolute requirement. Casting torches can be found in some hobby shops and in hardware stores. Several online shops also sell torches for the hobby metal caster. When buying a torch hobbyist should shop around in order to find the best deal. Always use caution when dealing with a furnace torch.
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Crucibles From the earliest attempts to make lead into gold and to the more modern use of making those empty soda cans into a replacement part for that model plane, crucibles have been an absolute necessity in metal casting. Crucibles are placed inside of the furnace where the metal is placed and then melted. The crucible then collects the melted alloy which will then be poured into the model. Since the crucible will be holding metals melted at extremely high temperatures the crucible will need to be created from very strong material. The durability of the crucible will add a certain aspect of safety to the metal casting process. Using a crucible that is low in quality can result in shattering, which, let's face it, is never ever a good thing. Any crucible at any given moment can shatter or fail which is why using appropriate safety gear at all times is so important. In order to handle the crucible which will be red hot you will need to wear boots, jeans, and gloves. The tools for lifting the crucible from the furnace and then the tool for tilting the crucible so that the molten metal will pour easily into the mold will vary crucible from crucible. Those that make their own crucible will be able to create them in an identical manner so the same tools can be used. The idea of these tools is to make sure that the crucible can be safely and securely lifted and poured. You will never want to directly touch a hot crucible, even with gloves. For those that either can not or will not make a home made crucible can buy a crucible and tools from any of the online stores. A common material for crucibles is graphite as it can withstand the molten metal. Many who cast metal will prefer using graphite crucibles as it can prevent impurities from being introduced into the gold or other precious metal being used. Another option is the Silicon Carbide crucible.
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Metal Casting Basics Vol. 1 Silicon Carbide is a great though expensive alternative to the graphite crucible. A crucible made from Silicon Carbide can handle rougher treatment then graphite so if you are not particularly gentle with your toys then this is a terrific option. Yet another option available to the home foundry is creating your very own crucible. Many don't really recommend this since commercially created crucible tend to be more durable and will instill a bit more confidence in the casters. It is, however, possible to create a crucible as many of us will at one time or another. If you plan on creating your own crucible then keep this in mind. There are a few areas of home metal casting where you should not cut corners, these definitely include crucibles. The crucibles job is the transportation of incredibly hot molten metal which can easily exceed 1,000 degrees Fahrenheit and is really the only thing between you and this metal. When you plan on melting metals with extremely high melting points you will need crucibles made from material that will cost a little extra. Spend that money and do so gladly since it is just a small price to pay for your safety. Crucibles should only be used to melt one kind of metal. If you have always melted aluminum but decide to try melting brass then you will need a new crucible. This is done for safety reasons. Remember, a crucible is not meant to last forever. Always check your crucible before use to make sure there are not cracks or imperfections if there are then do not use that crucible. Crucibles come in a variety of sizes and can be made from a variety of materials. It all depends on the type of metal to be used and the size of the job. Never skimp on the price of this tool and always follow safety guidelines and use common sense when dealing with a hot crucible.
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Cupola Casting Cupola furnaces are the easiest and most economical furnace to work with for the small foundry owner. Hobby metal casters are always on a look out for a cheaper alternative which will provide safety and yield quality results and the cupola furnace delivers all this. The common appearance of a cupola furnace is that of a smokestack. The furnace can be of nearly any size which is perfect for backyard metal casters. Commonly, the cupola furnace is supported on four legs with a drop bottom to remove any waste from the furnace. This type of furnace does not use a crucible so the metal caster will place the metal to be melted inside of the furnace. The furnace is fitted with a sprout and runner to pour the molten material which is called a taphole. Sometimes cupolas are fitted with a way for slag to be removed. The slag tapholes are located near the back of the cupola a little higher then the other taphole. The refractory used in cupolas are usually brick with the bottom being clay and sand as this is just temporary anyways. Cupola casting usually involves working with iron and bronze, though other alloys like aluminum can be melted as well. The common fuel source for cupolas is coke with limestone acting as a flux. Air can be pumped in to increase the burning of the coke. When the coke is hot enough the alloy is introduced in the top of the cupola. Some will place the alloy then fresh coke and then more alloy. The molten alloy will drip through the coke to collect in the well near the taphole. When the level of the molten alloy is high enough, the taphole is opened and then alloy runs into a ladle. When enough has poured the taphole is closed with the use of a refractory plug. Remember, cupola casting does not involve a crucible. Crucibles are traditionally used to melt the alloy and the collect it in the molten
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Metal Casting Basics Vol. 1 state. With the use of tongs the crucible is carried to the mold and poured. The ladle takes the place of the crucible in this regard. The metal caster pours the molten alloy which is in the ladle into the mold. The most common metal casting process is Sand casting which lends itself well with cupola furnaces. Cupola furnaces can either be purchased or constructed. Many hobby metal casters prefer to construct their own cupolas finding it difficult to find a furnace to fit their size requirements or their budget. Cupolas have been made from coffee cans large pipes and really just matters on what materials the caster is able to procure. By making your own furnace you will be able to customize it. Many will need a furnace to be small and portable. No one wants to leave a furnace out in the rain, after all. The chances are pretty good that if you are into metal casting then you have some of the technical knowledge needed to make your own cupola furnace. If not, then it is worth a shot just be extremely careful. You may want to find someone in your community that can aid you in your endeavor.
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Die Casting Metal Casters have the luxury of choosing between several casting methods to accomplish their goals. Often times the metal caster chooses one method and sticks with it for several years until need directs him to another. Of course, there are those adventurous few who like to sample each casting method to find the best fit. Sure, sand casting might be the most popular but what about Lost Foam or Investment? What about Die casting? Die casting is used by industrial foundries and manufacturers to create practically anything and everything, such as die cast cars. Many small foundries, like the one in your garage, backyard, of workshop may find that die casting is really just not economical. But who said that having fun and trying new things was ever economical? The process of Die Casting involves a simple concept. The molten metal is injected with high pressure into the mold or mold cavities. The mold used in die casting can have several small civilities of either the same pattern or different pattern. The name Die Casting comes from the molds which are called dies. These molds are reusable and are often made from steel but other alloys can be used as long as they can withstand high pressure. The reason dies must be created from metal and not from sand or other material is due to the high amount of pressure used to get the molten metal into the mold. If sand molds were used in a Die casting procedure then the mold would crumble. There are plenty of advantages of using dies in a casting procedure which makes this method desirable for anyone wishing to create a high volume of similar castings. Die casting is perfect for anyone that needs to make a lot of the same thing without any quality or pattern deviation. This is especially helpful in certain industries where
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Metal Casting Basics Vol. 1 quantity and quality count. Many hobbyists may have no use for die casting on a practical basis but will often try at least one Die casting for the sake of trying. There are two types of machines used in the Die Cast procedure. These machines are essentially the same and are called the Hot-chamber and the Cold-chamber. The Hot-chamber machine melts the alloy and feeds it into a section of the machine referred to as the gooseneck. A piston then forces the alloy into the mold. A separate furnace is not needed but the draw back of this is that metals with higher melting points can not be used. The Cold-chamber is used for metals that can not be used by the Hot-chamber such as aluminum and copper. A separate furnace is needed to melt the alloy which is then poured into the injection cylinder and then shot into the mold. The advantages of using Die casting vary but the most noticeable advantages are the repeated quality, smooth casting surface, and the quick production of casts. While the initial cost of Die Casting exceeds several of the other casting procedures, those that need a high number of casts in the shortest amount of time possibly will benefit greatly from the investment. Die casting is commonly used to create commercial goods as it yields a high volume. The molds, or dies, used vary in life cycle depending upon the material used to create the die. The die can have one cavity or several cavities depending upon the need. Everyone should try die casting at least once if they can afford the initial cost. Besides, who knows when you'll need a small battalion of metal soldiers which can be made quickly and easily with die casting.
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DIY Casting Furnaces The most noticeable item in any backyard foundry is the furnace. This is no surprise really, because without the furnace the entire metal casting operation would be nonexistent. The furnace can take really any size and form depending upon the need and budget of the metal caster. What really makes home metal casting furnaces really unique is how many of them come into creation. Sure there are plenty of companies that will gladly sell furnaces for the hobby metal caster and while this can be a viable solution to your furnace needs many metal casters prefer another method. Making your own furnace is not as far fetched as it may seem and if you already a Do It Yourselfer, chances are you will have the needed skills and tools in your workshop or garage already. There are a variety of reasons why people make their own furnaces. The most common reason is fulfilling a need. Many hobbyist and metal workers find out, to their dismay, that the local commercial foundries can not make the needed part or if they do, they feel the need to charge an outrageous sum. Not to mention the fact that the traditional methods of metal casting is quickly becoming forgotten as the industry turns to electric furnaces. So many hobbyists find that constructing their own furnace is an absolute necessity and a great way to preserve a piece of craftsman history. The artisans who use metal casting to create sculptures and other pieces find that making their own furnace grants them a greater amount of control over the entire process. This is actually how many people get into metal casting to begin with. Most likely, your first furnace is going to be a small and rather simple one. There is really no need to run before you can walk when it comes to something that will be using intense heat and melting iron which can be rather dangerous.
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Metal Casting Basics Vol. 1 Home made furnaces have been constructed from coffee cans to trash cans or sheet metal welded together. While there are a few components that really should be bought like the retractor to line the furnace walls which should be resistant to high temperature for a prolonged period of time along with special connectors and regulators, most of the furnace can be created in your own home. You should be able to find most of the components that you can not make at hardware stores or plumbing supply stores for relatively cheap. Along with the furnace parts you will also need to buy a crucible which will hold the metal as it melts along with the appropriate tools that you will use to handle the crucible. While you are at it you might as well buy all the safety equipment like gloves, protective eye wear, and leather shoes. There is other safety equipment that you will need depending on the type of work and the type of furnace you are going to make. Most likely, your first furnace is going to be a simple cupola variation. The cupola furnace which is going to resemble a smoke stack is a simple design and is relatively easy to make for anyone with mild craft skill. This type of furnace will not require a crucible since you will be able to pour the molten metal from the furnace itself into a ladle that can then be poured into the mold. DIY casting furnaces are a great way to connect yourself with your metal casting work giving you more control. While building the furnace can be complicated at first, once you delve into it you will find the experience enjoyable and fascinating.
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DIY Casting Movement The Do It Yourself movement is certainly not a new one. The term, DIY was popularized in the 1950s but the concept has been around for ages. The concept behind DIY is undertaking a variety of projects either home improvement, restoration, or arts and craft without the help of paid professionals. Recently the DIY movement has received a boost of popularity with the aid of the internet. Many are finding that DIY projects are easier to undertake with the help of instructional websites which provide step by step instructions and real advice from people who have actually accomplished the DIY process. Several of these sites provide ideas, photos, message boards, and a sense of community for Do It Yourselfers that was simply not available years ago. DIY projects can include any number or projects and ideas. Certainly the most common projects include home improvement such as cabinetry or installing plumbing fixtures, but one of the oldest DIY projects has to be metal casting. The DIY casting movement has been around ever since metal casting itself has been around, which is quite some time. Metal casting is the act of taking molten metal and shaping it with the use of molds into something new. Metal casting has been used in the ancient world for the use of making weapons, jewelry, and even religious icons. Today, DIY metal casting is used to create parts and items for use in a variety of hobbies and restoration projects. This includes home improvement items as well. Metal casting can be used to make door knobs, cabinet handles, and other such items. For hobbyists, small model parts and miniatures can be created. Even artists use metal casting for sculptures and jewelry creation. Metal casting possesses the true spirit of Do It Yourself. Many metal casters are drawn to the skill because it provides a cheap alternative to purchasing items or having commercial foundries make custom items. Nearly everything used in metal
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Metal Casting Basics Vol. 1 casting can be made by the caster. The furnace, molds, tools, and many others are made by most casters. Like other DIY projects, the DIY casting movement is being helped along my communities that are found online. These communities act as meeting grounds for casters to share and exchange knowledge and ideas, not to mention blueprints for furnaces and ingredients for casting materials. Metal casting is the pinnacle of DIY projects as it involves the fabrication of items from metal. After creating a mold of the desired item the caster will melt down iron, brass, or aluminum in a furnace. The molten alloy is poured into the mold and allowed to cool. The cast is removed to reveal a copy of the original pattern. There are several casting methods so undertaking a DIY casting project can be very involved and addicting. In the spirit of DIY, metal casters strive to make the best for the least. A great source for aluminum is soda cans and many casters gladly travel to scrap yards for iron or brass. The DIY casting movement is really gaining steam as many realize how cheap and fun this alternative is.
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Gravity Casting Metal Casting is more than just an excuse to play with molten metal it is actually a great way to create art and complicated pieces of machinery or other items that would otherwise be nearly impossible to make. Metal Casting is really a great way to save money...while playing with molten metal. The reason that Metal Casting has survived the test of time is a matter or efficiency. Some of the earliest casting examples have been found in China dating back thousands and thousands of years. In fact every major civilization from the Egyptians to the Romans practiced metal casting. This skill came back into vogue during the Renaissance and has continued to advance and evolve from there. While Sand Casting is the most popular casting process there are many, many more processes available to the backyard foundries. Not everyone is going to be casting heavy pieces like engine parts or cast their own motorcycles. So for those that just want to make decorative pieces you will not be using the same casting process as these heavy duty casters. For artists creating small scale statues or embellishes and for hobbyists that need a decorative touch to their model plane or boat might want to consider using gravity casting for their needs. Gravity casting seems to be especially useful when dealing with aluminum and other light alloys. The basic idea behind this casting process is pretty much exactly what the name suggests. The metal is introduced into the mold by the force of gravity. Most other casting process either use natural pressure difference like the kind in certain sand casting procedures or they use forced pressure like in centrifugal casting to get the molten metal into the mold. One of the most common uses for gravity casting is when permanent molds are going to be used. Also called a die, the permanent mold is really only economical
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Metal Casting Basics Vol. 1 for those planning on using the same mold numerous times and will need to keep the quality at a constant level. While some temporary molds can be repeatedly used the quality of the finished product will begin to suffer over time. With die molds the quality will remain the same. Die molds should be seen as an investment. Yes, they will be more costly then other molds; however they will outlast cheaper options for molds. With Permanent molds, they are created using cast iron, steel, and other metals. Gravity casting is used for the permanent mold process with pleasing results. Gravity casting is usually used when the finished product is more visually based then structurally based which is why this method is a favorite of artists and even some jewelers. The loss of strength is due to the lack of pressure used in this process. For those that need the strength but still want to use gravity casting, more of the molten metal will need to be used which will increase the weight. Relying on gravity will take patience, although it will be needed for larger products. If you have never tried gravity casting then you should, because you just may be surprised by what such a simple thing like gravity can create. For the sake of humor, make an apple and see what happens.
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Metal Casting Basics Vol. 1
Iron Casting Many believe that iron casting is just simply out of reach for small furnaces but this is not the case. While alloys like aluminum are more prevalent in home foundries. Artists and hobbyists have also used brass, bronze, and even iron to fulfill their casting needs. Industrial foundries commonly use iron for a variety of items like cookware, like cast iron pans, and even bridges. Casting iron provides an easy and effective method of making such large structural pieces and even smaller pieces for around the home. The most common furnace type used by home foundries is the cupola furnace. The cupola is a basic furnace type that does not need a crucible as it allows the caster to pour the molten metal directly from the furnace into a ladle which is then poured into the mold. Cupola furnaces resemble smoke stacks and can be home made for those with enough confidence and some mechanical know-how to attempt it. The fuels used to heat the metal in a cupola furnace depend on the caster's resources and preference. Many will use propane and some will use coal. There are a select few that will use waste material such as old scraps of metal and the powder at the bottom of bags of barbecue coal to fuel the cupola. For iron many would recommend the use of propane, but there have been some casters that have succeeded with waste material. Don't be afraid to experiment with different fuel types to find the perfect fit for your furnace and need. Finding a source of iron can be difficult and a trip to the scrap yard might be in order. This is just one of the exciting ventures that metal casting can provide you. After you locate your iron you will need to prepare your mold. This is assuming you have a pattern in mind that you want to cast. If not, then go ahead and figure something out even if it’s a small piece in order to test your iron casting ability. Since sand casting is the most popular casting method you might want to
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Metal Casting Basics Vol. 1 use it for the iron casting especially if you are familiar with the method and not with iron. After making the sand mold and placing the runner for the molten iron you will melt the metal. The melting point of iron is 2,800 degrees Fahrenheit or about 1538 degree Celsius. Since all metals melt at different temperatures don't be impatient if iron takes longer to melt and don't be surprised if it’s quicker. When the molten iron is ready you are going to pour some into a ladle and the pour that into the sand mold. The sand mold is held in place by the cope and drag, which is the top and bottom part of the mold. The runners are in place in the mold to allow the molten iron a place to enter. When the iron is cool, remove the cast from the sand carefully and there you have a cast of iron. As with all metal casts, you will need to follow the appropriate safety steps to avoid any accidents. Accidents with molten metal will always be very painful so make sure you wear gloves, jeans, boots, and a long sleeve shirt. You may also want a heavy duty leather apron and a pair of goggles. Iron casting is a great way to create restoration items or pieces for around the home and even for artistic purposes.
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Lost Foam Casting Lost Foam Casting is a relatively new casting process compared to other metal casting procedures that date far back into antiquity. The first patent for Lost Foam Casting was made in 1958 but it was not until 1964 that what we know commonly as Lost Foam Casting was introduced. Lost Foam Casting is a form of Investment Casting much like Lost Wax Casting. The key material of Lost Foam Casting is of course foam which is not used in other metal casting methods. The use of foam has many benefits to the artisan like ease of use and shaping and the relative inexpensive cost of the material. Each casting is going to be one of a kind since the original casting of foam is lost during the process. The foam original will be replaced by the molten metal unlike the Lost Wax Casting where a wax mold is made of the original and then coated with a ceramic shell in preparation for the molten metal. Luckily, most foam is pretty inexpensive so the loss of the original shouldn't pose a significant financial loss, just an annoying creative loss. Foam is easily shaped by hand held tools but even still some practice may be needed to prefect the sculpting of the material. You will need to place a sprue into the foam which will allow the molten alloy to spread into the foam and adopt the shape of the item. Packing the foam and sprue in sand is a good way to insure that the mold will retain its shape through the pouring process. The metal will replace the foam by vaporizing it, and it is really quite a sight to behold. Though there are many who prefer to adopt the procedures used in Lost Wax Casting for the Foam casting. After spruing the foam original you are going to dip it into a solution to create a shell and then pour the metal. The goal of this is to create a cleaner surface.
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Whichever method you choose is really up to you. Many use Lost Foam Casting a quick and easy way to create something when visual appearance isn't all that important. Many refer to Lost Foam as the "quick and dirty method". As for the type of foam to use you are going to want to steer clear of anything that will give off toxic fumes when heated. Urethane foam is toxic. The popular foams to use are the polystyrene kind which is used to pack electronics and the polystyrene foam used for insulation. These foams can be found at many home improvement stores and even a few all purpose retail stores. Lost Foam Casting is kind of like alchemy, transforming something inexpensive into something invaluable. Whenever you cast, make sure to take all proper safety precautions and wear safety gear. Always wear a long sleeve shirt, jeans, and the proper shoes. Don't forget eye and face wear and of course gloves. Never forget that you are dealing with material that can very easily harm and disfigure or worse if not handled properly. Many first time casters begin with Lost Foam Casting since it doesn't involve mold making but if you are experienced and never attempted this method you will still want to be careful.
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Lost Wax Casting Lost Wax Casting is an ancient technique that has been used to create very complicated metal castings and involved pieces that would other wise be impossible either because of economic reasons or manufacturing reasons. Everyone from small jewelers to large industrial foundries can use Lost Wax Casting. This process is also called Investment Casting when it is used in commercial industries. While jewelry makers are the primary ones to use the Lost Wax Casting, many others use it to achieve a number aims and goals. Lost Wax Casting is the ideal and preferred method for artists who are interested in making items like sculptures or rings from a variety of alloys like bronze, steel, or copper. This process is quite involved but not all that complex as long as you have some kind of metal casting know-how. For anyone wanting to experiment with different casting methods Lost Wax Casting is a great option because it involves a few materials and methods that are not normally found in other methods like Sand Casting. The most noticeable difference of Lost Wax Casting from other castings is exactly what's in the name; the wax. To use Lost Wax Casting you do not necessarily have to be an artists but some skill in sculpting might be nice. You are going to start off by creating a sculpture from wax that will be the original. You will then create a mold of the original. The mold is usually created from plaster with latex lining to help preserve the details of the original. If this is your first attempt at Lost Wax Casting you may want to make an original without a lot of detail just to get the feel for the entire process and so you do not become discouraged if something does not work out. Remember metal casting is a skill that must be learned by research, trial, and error. Chances are that you will not be completely successful, the first time around. The original piece is usually lost after the construction of the mold. This is normal and if you do want to prevent this from
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Metal Casting Basics Vol. 1 happening you can create the original from material other then wax like a metal alloy. When the mold is ready you are then going to pour molten wax, you're not ready for metal just yet, into the mold. The amount of wax needed for this step depends on the desired thickness. Once the copy is ready, you are going to remove it very carefully from the mold. You will remove any of the impurities from the copy. This is called chasing. You will then sprue the copy. Spruing is the act of carefully placing paths that will let the molten metal in and air out. Afterwards, a ceramic shell is created around the copy. The shell isn't really ceramic but a combination of liquid silica and sand. Traditionally, and in some areas still, animal dung and dirt is used to create the shell. The choice of which shell material you want to use is up to you. The shell is hardened in the kiln and the wax melts out. If you want to reuse the wax then collect it during this step. Wax can be reused a number of times and if you are on a budget or are just trying out different designs and methods, collecting the wax is encouraged. Once the wax is gone and all that remains is the hollow shell you will want to run water through it to make sure there are no leaks. If there are then you will need to patch them before pouring the molten metal. You are going to want to reheat the shell before pouring the metal to avoid shattering the shell. The shell is still on the sprue tree so pouring the metal is an easy process. When the metal has hardened, then break the shell carefully and remove the cast. Afterwards, it is up to you to finish the piece to your liking and preference. The Lost Wax Casting process is an enjoyable experience but it does use a few tools that you might need to purchase before hand, like the wax and spruing tree. At the very least, you might want to try Lost Wax Casting once or twice to get a feel for it. This way you have another casting process at your disposal.
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Resin Casting Metal casting is known and loved for the high temperatures, glowing molten metal, and the possibility to make nearly anything. Metal and their alloys are not the only things that can be used in casting. Casting in plastic, most notably resin casting, is becoming popular with artists and jewelers looking for something odd and unique. Resin casting does not involve the use of furnaces, crucibles, or casting sand. In fact all one really needs for resin casting is a mold, some resin (of course), and time. There are actually two forms of resin casting. The first kind is the one that more closely resembles metal casting, uses a mold and even gates and runners if it's complex enough. The second type of resin casting is simply incasing an object in the resin. An example of this is using an ice cube tray and placing an object like a small pendant in one of the tray's cavities and then filling it with the resin solution. After the resin dries you can pop it out of the tray. The pendant is now encased in hard plastic. This form is usually employed by jewelers and crafty moms but tends to be fun for everyone no matter age or experience. At the very least it's a great way to get rid of some of the clutter around your house and disguise it as art. You can cast leaves, coins, and other objects in the resin to make anything from charms to magnets. Resin casting using mold is generally used by those who work with models and miniatures. Resin casting is a great way to make several pieces at once so you can avoid shelling out money you may not have and waiting several weeks for delivery of your items. Who has that kind of time anymore? Like metal casting, resin casting will require you to build a mold. If you are fortunate enough then you can easily find pre-made molds, especially if you are working with miniatures. If you don't feel like buying these pre-made molds or just
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Metal Casting Basics Vol. 1 like doing things the hard way, then you will have to make the mold yourself. Don't worry, it's still fun. You will need to find a molding box this will hold the rubber that will be used to make the actual mold until it dries. Many who work with smaller objects find that working with toy building blocks to create this molding block work extremely well and will provide added convenience. A wooden box will work as well, of course. The box, or flask, will not have a top or bottom, just the four walls. Place molding clay at the bottom of the flask and insert your original. Make sure to add a way for the resin plastic to enter the mold. This cup or funnel should be placed at the top of the mold. You are going to prepare the silicone rubber and catalyst which will be used to create the mold. Follow the instructions on the labels since each type will vary. A process called degassing can be used which will remove all the air bubbles from the rubber. This is a fun process involving a vacuum pump. Slowly pour the rubber into the flask, covering the original. This can take up to a day to dry, so be patient. Remove the molding clay and repeat the process using the bottom part of the flask, or drag. You should have two parts now, with the original in the middle. When dry, remove the mold from the box and very carefully split the mold to remove the original. Place the mold back together and prepare the resin solution, follow the instructions to the letter. Pour the resin into the top of the mold, where you placed the cup. The set time for the resin should be stated on the bottle, but for most it will take up to 30 minutes. When ready crack the mold open and remove the cast. Resin casting can be a great family craft project but just make sure to follow all of the safety guidelines. This type of casting can still be dangerous even though you are not dealing with molten metals. Often times, the solutions and chemicals used in resin casting are poisonous if consumed. Not to mention that resin casting can be a bit smelly so working outside or in a well ventilated room is advisable.
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