Investment Casting

Investment casting is the process of creating a mold in investment plaster ( a specially formulated refractory plaster ) by using a sacrificial pattern made from something that can be completely burned out of the cavity that metal is then poured into to create the metal component,  this process has been used in one form or another since antiquity ( it's also widely used now in industry as it produces components that are very accurate and require very little finishing ).

This is a record of my first attempts.

Here we start with the 3d printed models, they are sitting on UK 5p pieces, they are approximately 15mm tall,  from these rubber molds were constructed and this was used to create the wax copies, the resolution and the detail in the wax is really quite astounding.

Here a number of the wax bunnies have been assembled into a wax tree and the flask has been filled with investment plaster.

Here you can see the casting as it comes out of the plaster and here is one of the bunnies that has been cleaned up, the 'dimpled' pattern on the surface of the metal was due to the mold still being too hot for the metal when it was poured. ( the metal used is a zinc aluminium alloy ZL12 I believe ).