Lew,
The advice you are getting here is good. However, since I have been making precious metal castings for 50 years, I will throw in my 2 cents worth. First of all, if you buy all new equipment, the costs will be about what Jerry and Rolfkt have noted. But you can go a long way with used equipment. I just helped a friend of mine set up to do fairly large centrifugal and vacuum castings for about $600. This included a vacuum pump, a centrifugal casting machine, a burn out oven, a vulcanizing press, flasks, a wax injector, a few casting crucibles, and a Prest-o-lite torch rig. The following are some examples of the type of castings you can do with the equipment just noted:
Solid 18K gold and ivory letter opener and reading glass set with emeralds and diamonds
Silver and gold muzzleloading jewelry
Brass thumbpiece
Replica Spanish coins
18K gold eagle cheek piece inlay
These are all fairly small pieces, but I have cast parts as big as butt plates and trigger guards with the same equipment. Very long parts, like a rifle trigger guard, can be done in two pieces in a centrifugal casting machine and then joined as Rolfkt describes for an assembled guard. However, the casting can have any or all the detail you want without having to hammer it out each time. Original patterns can be one of a kind carved from wax. Or, a pattern can be carved from plastic or wood and a silicone rubber mold made so that multiple parts can be quickly duplicate by injecting wax. If the original pattern is made up from metal, you can vulcanize a mold like the following and also injection mold multiple patterns:
Spanish coin:
Metal patterns:
Lock parts and their molds:
Duplicated wax patterns:
Now these lock parts are cast in steel, which the equipment I will talk about cannot do, but the pattern process is the same - (these lock part patterns were then handed of to a foundry that did lost wax steel casting).
To do castings like these, you will need some or all of the the following equipment, depending on how you want to do castings. You can make any of these castings with a vacuum casting set up - even the largest ones. If you use vacuum, you will not need the centrifugal machine. If you carve the wax patterns one at a time, you will not need a vulcanizing press, mold rubber, or silicone rubber mold making materials. So the following list are just generic types of casting equipment and you may not need everything here:
Centrifugal casting machine - new ~ $400. Used, I recently bought one for $60 (be careful here about the condition of the machine and its size. It is easy to make small castings in a large machine, but impossible to make large castings in a small machine.)
Burn out oven - New, anywhere from $700 to $3000. Used, $150
Vulcanizing press (for one type of mold making) - new $750, used $50
Vacuum pump - for investment mixing and casting. New $500 to $800, used $100
Torch rig (I use an air fuel type like a Prestolite for non ferrous castings). New $175 (plus an acetylene tank), used $25
A vacuum casting machine is expensive new, but can also be found for a very reasonable amount used. However, A vacuum casting machine is also very simple to build. It is basically a metal plate (steel, aluminum, or copper) with a hole in the middle connected to a vacuum reservoir and
a vac pump with a valve. The plate also needs a heat resistant gasket to set the hot flask on. Not hard to build, if you are interested.
Bottom line, this type of casting is not a walk in the park, but it can be done with used equipment. It just takes a little patience to judiciously round up the gear you need.
