I had posted a photo of a pistol butt cap yesterday , received some question and decided to share some on my experiences. I teach a seminar which utilizes cast mounts derived from original Flintlocks, so having authentic form and high detail are desired. I make the frames from cabinet grade plywood scraps cut and assembled to approximated the shape of the part. The molds should be as smooth as possible and surface sealed. The mold pictured shows the transparency of the mold, enabling a clear view to cut out the original master. This mold is complex in that a pull core is used to make the ramrod pipe a tube. I am using a Shore 50 (firm) rubber from PolyTech. It enables me to use a higher PSI for wax injection, without deformation. I use a 60 PSI pressure chamber to cure the rubber. This reduced all bubbles to microscopic size. This wax is a new product to me. It has a good memory and is much less brittle than some I have tried. Not having a foundry available nearby, I have to carefully package and ship my waxes, hence the need to a non brittle, flexible wax.
I am sure there will be some additional question, so fire away.