making casting molds?

[Blue EagleBum]

New to the knife making addiction. I have some brass and would like to cast some of my own bolsters. I will have a propane forge built in near future. What material can I make a casting mold from. Refractory, High temp RTV, plaster of Paris? I also want the molds to be reusable.

[Doug Lester]

Plaster of Paris is not suited for casting you will need something that will stand up to the heat of molten metals like brass or bronze. It's called casting investment and you can find it at a jewelry supply. The first thing that you need to get is a good reference book on metal casting. Tim McCreight put out a good basic book on it. It will lay out the various forms of casting.

Reusable molds are a bit on the expensive s##e and most of them are made to cast wax models for wax loss casting. You could also make a master model and use that to make a sand casting mold. Do some reading, as I have mentioned, and go onto some casting web sites and pick up some tips there.

Doug

[Gary Mulkey]

Unless you have professional breathing protection I wouldn't recommend casting brass as the fumes can do some very nasty things including killing you. If you are sincere in wanting to cast bolsters then bronze would be much preferable.

Also you will have a hard time bringing either brass or bronze to melting in a typical forge. Do some reading on foundries, ovens, and crucibles and you will see what I mean. I don't want to rain on your parade but foundry work takes a lot of preparation & specialized equipment to do safely. SAFETY FIRST.

Gary

[Larry Peterson]

Friend,

I do a little casting of guards and pommels. I use the lost wax when it has to be right on the money, and "Petrobond" sand when I can clean it up on the grinder. I melt my metal (white bronze and scrap brass) in a little clay , propane fired furnace. The crucibles are numbered according to the number of pounds of aluminium they will hold. I commonly use an 8, 6, and 4 pound crucible depending on how much I need.

If you are only pouring a little for a single guard or pommel, the cutting torch works well with a jewelers crucible.

The casting plaster is available in 20 pound bags at almost any jeweler supply. 20 pounds does a lot of casting.

Lots of wonderful information on u-tube and other sites on the internet.

Best wishes, Larry Peterson