Wednesday, January 18, 2012

Wax Patterns ready for investment

Shown here are the two S&W hand guns ready to be subjected to the refractory mold process. In the lost wax casting method the term is investment. What you see here are the two guns made from wax. The red material is wax as well and you see the two paper cups.

The cups form a funnel in the mold. The red wax attaching the cup to the gun is called a sprue, the little red wax from the butt of the gun and from the holster to the cup are vents. Imagine trying to pour water into a pop bottle, the difficulty is the air must rush out as fast as the water pours in. By venting we can rapidly pour bronze into the molds.

Everything you see here gets invested (covered) in refractory mold material. We use Shell-Spen, a liquid colloidal silica and sand to build up coats of the mold. When fully coated the material will be 1/4 of an inch thick. The wax will then be melted out of the molds, the molds heated to 1800 degrees then bronze poured in where the wax was. The result is everything you see here will then be bronze. The sprue with cup and the vents will be cut off leaving the gun.

I will take pictures of the process to help illustrate what I'm attempting to explain.

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