Not sure where this fits. But I have enjoyed casting. First it was casting lead fishing tackle as a kid and adult. Then came casting resin and pewter in RTV molds. When I was a kid in Jr high I did a little bit of sand casting in shop class and some lost wax casting in arts class. All of it I find very rewarding. I want to step up my game and cast aluminum and brass and do some sand and lost wax casting. In order to do this I need something with a bit more umph than a propane torch. So starting last spring I began researching foundry furnaces. As a DIYer I won’t buy what i can make. And there is a plethora of info on the web about making mini or micro founderies. Here is the one that gave me the basic Idea.
I am going to make mine using an outer coffee can and an inner can qt stain can and the bottom of another coffee can cut down to make a lid. You mix plaster of Paris and sand for your refractory and suspend the inner can in a solid mass of refractory. I will drill a hole through both cans to fit a 3/4 galvanized pipe. Then I will pour the refractory in and around the inner can and the burner tube. Here are the piece of my furnace.
The little stainless tube is siliconed in place only for filling the lid with refractory. It can then either stay there or come fall out. Its just to form the vent hole in the top. I am thinking of redoing it and making the hole larger before I pour it so I can feed in small amounts of metal without removing the lid. But at any rate this will give you the basic idea. Now in the vid they don’t use an inner can. They form it with a plastic cup and then remove it. Not sure if thats necessary. I am thinking the inner can will add some strength and keep the refractory in place even if it decides to crack. At some point the inner can may burn out but if it does it does.
And finally the burner. I am making a different version than the one in the vid. I am using one in another vid that is a little larger and looks as if it puts out more BTU if flame, noise, and fury are any indicator. I took an old propane weed burner and took off the end and then fashioned the burner mechanism to screw on it. I am hoping the burner mechanism with stay poured into the furnace and I can unscrew the weed burner if I need to separate them. These burners that people are making for furnaces and forges are a pretty simple affair whereby an orifice is either made or bought (mig welder feed tip) and is suspended by set screws into a bell reducer and a pipe. As the gas passes out of the orifice and down the tune it creates a venture in the bell reducer pulling in air as well adding to the fury. Propane is supposed to produce enough BTUs to melt brass. We will see.
Here is the one I basically copied I have it started where he fires it up. If you want to build one you have to watch fromt he beginning.
Hopefully by the weekend I will have a nice little foundry for melting brass and aluminum. Stay tuned because I have a recipe for making my own casting “green” sand and plans for a sling caster where by you swing molten metal around your head.