I have always been unhappy with the volume of metal I could melt at one time with my torch and little crucibles. It was time to step it up, and the challenge was how to get it done on the cheap. Much research on the InterWeb led to a few designs for home-built forges and furnaces. I opted for the trash can variety with my own "features" added in.
First of all, we needed a vessel. The galvanized steel bucket whose bottom was blown out by the ice two winters ago seemed a likely candidate. I needed to create a cavity into which I would blow fire, and a galvanized stove pipe was a nice choice. I bored some holes to insert a steel rod to act as a prop for the crucible. I filled the space between the steel sleeves with sand, and put some fire to it.
Sand dries out, and when it does, it can be really fine. This is how I made a really neat hourglass that required some patching. We dumped out the sand, packed in some fiberglass insulation and brazed the hole where the steel rod went through the stove pipe, and put it all together again. After several attempts to get it sand tight, I was satisfied. More fire.
The true intent of this furnace is to refine silver waste from my print shop, Working Words & Graphics. We loaded the crucible with silver dust and some larger pieces from the silver recovery machine, and let it go.
After a while, we got a nice red glow inside and the smoke started pouring out of the crucible. Heat burns off the sulfur and other impurities, which takes several hours to complete. We melt, cool in water, melt again, cool again, and repeat until the silver is clean. This can take three or four trips to the bucket before I'm satisfied.
As you can see below, the whole rig stinks of something out of Mad Max or Conan the Barbarian. Nevertheless, we get some neat results from the refining process.
The Furnace Itself
Down the Hatch
Some results of pouring ~ 1 lb of molten silver into a 5 gallon bucket of ice water.
Leave a comment