Ray-Vin Lost Wax Casting Primer

Waxes


You can use just about any wax for your investment casting model. In ancient times bee's wax was used. However, waxes specifically formulated for carving (or machining), fabricating and injection molding will be much easier to work with than plain old candle wax.
The jewelry industry offers lots of different waxes in many shapes and sizes. There are even water-soluble waxes. Above is one of many assortments offered (click image for supplier). Your best bet is to get a catalog or find a jewelry supply house near you.

You can carve your model using a variety of tools; knives, files, roto-burrs to mention a few. You will find the harder waxes to be stronger and easier to work in this manner. Machinable waxes are used to test CNC programs and are also useful for carving. Some of these waxes are similar to tough plastics, but easier to cut.

Fabrication involves welding different pieces of wax together to arrive at a final shape. Wax is fused simply by applying a heated metal tool to the joint of the two items to be joined. The heat melts the wax welding the items together.
A simple tool for fine work is just a cork with a straight pin stuck in it. Heat the pin in a flame and then apply the tool. Experiment first with scrap because too much heat and you will ruin your model by melting a big puddle where you only wanted a small spot! For heavy work, a soldering iron may be used.

For production in any volume, you may want to make a mold and inject your wax to quickly make many patterns of the same size and shape. RTV Silicone rubber is useful for making molds from original models. I may go into this at a later date...

Some waxes have a high coefficent of expansion. When they warm up, they expand and may crack your investment. See burn out for more information.