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Metal Casting

Metal 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.

Weapons and Sculptures have been made using bronze since the begining of its discovery by man. Artists tend to navigate towards Bronze because Bronze will be able to pick up the tiniest details of the sculpture. 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.

Metal 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 often charge outrageous prices for their services. Art Casting on your own is often times economical and just smart.

Plenty of time should be allocated to the Lost Was Casting process as well as plenty of attention to detail because although it is simple compare to other methods, if you don’t have those two items, then you will be in trouble. 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. Sometimes it is a good idea to try a few other metals until you get the exact look that you are searching for.

 
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Metal Casting

Iron Metal Casting can be referred to as products made out of melted iron molecules. These molecules are, first, poured into mold and allowed to cool. They are then extracted. The casting properties depend a great deal on the foundry practice. They also depend on the cooling rate. Iron contains huge carbon concentrations. This content facilitates melting, simplicity of casting, and machining. Iron casting designs have a great variation owing to the property of iron to resist shrinkage during the process of cooling. The end product attains a great reputation for its strength and durability. Tensile strength ranges between 20,000 psi and over 60,000 psi. The values of hardness (without heat treatment) range between 100 and 300 BHN.

Some factors need to be considered while buying iron Casting . On the long list of things to check, the quality of the foundry that is to be used in products and procedures should be at the top of the list. This should be done because foundry practices determine the casting properties. The consumer might have a tough time in finding the apt one. Secondly, the concentration of carbon should be looked into. The percentage of carbon commonly ranges between 2.5 and 4%. An addition of even 0.Decreasing the tensile strengh by around 2700 psi is caused by just 1%. As youo can imagine, each foundry is run very differently which means that their casting procedures will be very different if compared to one another.

Green sand molding is the most commonly used type of Metal Casting . Normally, small and medium sized products are produced using this type of casting. Shell molding is preferred for bigger applications. One thing that shell molding does is to help the cooling of the mold that contains the heated metal. This process gives a better finishing to the final product as compared to all the other processes. Centrifugal casting is used for producing big cylinders and pipes. Both, producer and consumer would get highly satisfied if a proper blend of correct casting process and reputed foundry is made.

Iron castings are utilized extensively in machinery, automotive, and agricultural industry. Parts such as turbine and pump housings, dynamometer bases, compressors are made out of iron castings. Majority of manufacturers have the caliber to go for high and low production outputs. They are also entitled to go for short order runs. Sometimes you will find standard prototypes that will ensure the highest customer satisfaction and best accuracy possible. Some manufacturers provide finishing services like galvanizing, painting, and machining as well. In general, iron castings include alloy casting, ductile castings, and malleable castings. There are some terms relating to iron castings. They need to be known in order to get a fair idea of iron.

Brinell Hardness Number (BHN): It can be defined as the method used for measuring the hardness of iron. For iron castings, a metal ball of 3000Kg is put on a flat iron piece. After the removal of ball, indentation observed is recorded. This measurement indicates the value of hardness.

Tensile Strength: Tensile strength can be defined as the quantity of bending and stretching undergone by a material before tearing or breaking. Here the metal is iron.

Modulus of Elasticity: It can be defined as the ratio of stress to strain. This value determines the elasticity as well as the stiffness of the concerned material.

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