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 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.