oldbadger
Skanky Old Mongrel!
Wow!I've seen any number of reactionary (is that the right term?) furnaces-- made of various tin cans or other. I've seen some as small as a gallon can, with rock wool (basically spun rock fibers, won't burn, won't melt) as insulation. I saw a large one made of a galvanized trash can, too. Re-purposed hot water tanks, the works. There is also mixable cement material, you can get, that when cured, is fireproof, won't melt, won't burn, that you can use to mold your furnace.
Plain old propane will get hot enough to melt copper, if you use an air blower, and a home built torch (such that the flame is perfectly balanced between air and gas) and has a high enough BTU to keep the heat in, and use a heat retention furnace, often with the aforementioned rock wool or castable cement. Note: Ordinary concrete, or mortar, will burn if you get it hot enough-- it's basically limestone after all, and will react with oxygen in the air, if you get it hot enough. So don't use that.
I love the subject of home brew forges, I wish I had the health and money to do some myself.
I don't know if I will build a little oven/furnace or spend much money on gear. All I used (yesterday) to melt the 2oz of silver needed was a Butane ring which the crucible sat upon, bathed in flame, and a butane-propane torch which I pointed directly in to the crucible. When it was time to take the crucible to the mold I kept the flame pointing in to the silver all the way until I had made the pour.
The butane ring and cylinder is a camping one and I paid £3 each for the cylinders at a local general store and sprayed them silver because they were emergency cooking gear kept in the kitchen and my Missus preferred them that way.
The torch head was about £15 (I bought it years ago) and the butane-propane bottles cost £5.50 at the local DIY store.
I have ordered a proper propane torch on ebay £9, and the local DIY store charges £10 for propane bottles.
The Cuttlefish bones cost £1.41 each at the pet shop, and can only be used for one casting, but it was easy to prepare that one for the job.
So I don't think that I will spend much money at all on gear if I stick to just melting and pouring silver in very small amounts. Folks on google say that it gets expensive when larger quantities of metal have to be heated and poured.
Oh! The little brass pot in the photo contains borax powder, which is sprinkled over the silver to help it melt. I probably would have got nowhere without that. Google training vids sure are wonderful.