Lost Wax

[Dr.VanNostrin]

Say have any of you guys made custom parts using the "lost wax" or "investment casting process"?

I'm going to give it a go on a couple of projects. Wondering if anyone has some advise!

Thanks

[Dragonsinger]

Hi Doc
Not exactly models and not me. BUT Carol, My wife, did some jewelery in silver using the technique. So let me give you what we learned.
1) Where possible use fireclay and NOT plaster of paris. Plaster has bubbles and when you heat it, it explodes or fractures your mould. Ceramic clay for pottery is also good.
2) Get the largest sprue hole you can accept on the finished part and make certain that you have an enlarged depression for a pouring funnel into the mould.
3) Put in air vents at the highest points of the mould. A little bit to clean up is better than a cavity in the casting.
4) Weigh the filled mould and then weigh the empty mould. Wax left in MIGHT burn off or rise to the suface. Chances are it wont.
5) Cooled metal shrinks. On something like a lathe bed it can be as much as a couple of inches. the problem gets worse, not better, in smaller scales
6) Dig out some of the books by Dave Gingery. You will not do better.
Enjoy
Dragonsinger.

[Silver Dollar]

I've done a fair amount of lost wax casting using gold, silver and non precious metals. There's a lot more to it than making a mold and pouring in some metal. Some metals can be melted at pretty low temperatures and poured in fairly easily but some have to be literally shot into the mold either by vacuum or by centrifugal force. Check with a jeweler's supply company that deals with casting and that should give you some idea of what to look for. It's better to do a bit of research in the beginning than to cast something and wind up getting so frustrated, you may never attempt to cast again. If you need specific info, let me know and I'll try to help.