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Introduction to Lost Wax Casting
Charms, pendants, and rings are just a few items that can be made using a method called lost wax casting. In this process, a wax (or sometimes plastic) mold is used to create a piece of jewelry. This wax mold, called a pattern, is first weighed so the amount of metal required to fill the mold (gold, silver, etc.) can be determined. Then the mold is attached to a base, and a flask is slipped over the base. Once the mold is in the flask, a kind of plaster that looks like pan cake batter called... investment, is mixed up, put in a vacuum to get all the air bubbles out of it, and then poured into the flask. It is then left to dry and harden. This takes a minimum of two hours.
Once the investment is dried, the base and flask are removed. Now the piece is put into an oven to burn out the wax. Next a centrifuge is used to force the melted metal into the investment mold. Finally, the piece is cleaned up by filing and polishing it.
Read on for some illustrated instructions.Continue to 2 of 9 below.
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Lost Wax Casting SuppliesYou'll need sticky wax, designer wax, a stainless steel tumbler, a rubber base, a sleeve that fits over the tumbler, a tool for scoop the wax (I got this one at a ceramics store), and a lamp.Continue to 3 of 9 below.
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Preparing the Wax MoldAttach the sprue onto the wax mold using sticky and designer wax, and then weighed it to the amount of metal needed for casting.Continue to 4 of 9 below.
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Add Base to SprueAttach the sprue on the mold to the rubber base.Continue to 5 of 9 below.
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Prepare Casting TumblerAttach the sleeve to the tumbler to prevent spilling, and then weigh out the dry investment and mix it with water. Finally, set it in a vaccum machine to remove air bubbles.Continue to 6 of 9 below.
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After the investment is dry and has gone through a burn out process in a kiln that literally burns out the wax mold, your tumbler is ready. Take it from the kiln and set it inside the centrifuge machine so the hole lines up with the hole in the crucible.Continue to 7 of 9 below.
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Melt the MetalAdd your choice of metal to the crucible, and use a torch to metal it. Once it gets super hot, release the pin in the centrifuge (while the torch is still held over the metal) and then back off quickly because the centrifuge spins around. This forces the metal into the tumbler.Continue to 8 of 9 below.
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Casting CompleteOnce you stop the spinning, pull the tumbler out. Here you can see there is a circular piece of metal at the bottom of the tumbler. This is called the button.Continue to 9 of 9 below.
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Clean Up CharmThis tumbler must sit for about 1 minute before being plunged into room temperature water. The raw charm will be inside the goopy, wet investment.
Though the casting process has finished, you still need to clean up the cast item. The button needs to be sawed off, the charm filed, a jump ring added, and then you can polish it.