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Building a Foundry? Answered

So I've been experimenting with building a mini foundry made out of steel cans. I've experimented with several different fuels, fuel injection systems, oxygen injection systems, crucibles, and different metals. However, the only metal I've ever been able to melt with it is zinc. (if you don't know, zinc doesn't take alot to melt; only about 700F) My target metals are aluminum and copper, but despite over a year of experimenting, I've never been able to melt either. I would like to know what I'm doing wrong, or what I could do better. Here's the rundown of the furnace's construction:

The fuel I'm currently using is propane. The foundry isn't big, (you could fit it in a backpack) so I just use propane canisters for torches with a normal output line on the end. The line runs to a small piece of glass laboratory tubing with a tiny nozzle on the end which is about 1 mm in diameter. The propane shoots out as a stream and mixes with air utilizing the venturi effect. The propane mix then shoots into a large metal pipe about 2 cm in diameter. It then bends up at a 90 degree angle and enters the furnace, which is in essence, a steel can with a hole in the bottom. inside this is a steel can cut in half with a thick wire through it to suspend it above the burner. 

So what could be improved? When I run it at full blast, the whole furnace glows orange, but no metal melting happens...


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8 years ago

Seriously stop melting zinc straight away. It's underrated how dangerous it is when it's a fume.

I can melt copper in something the size of a coffee can.

Sounds like you are using something small?

I suspect it's your refractory, but I could be wrong.

Buy a JTH-7 Benzomatic hose torch, with a couple of adapters you can attach it to a standard POL fitting. Get a K26 fire brick, a coffee can, and some Kaowool. You sound smart enough to figure out the rest.

If you get stuck, I can point you in the right direction.


9 years ago

It;'s all about insulation - Keeping that heat concentrated on the crucible.

Look right >>>>>> and there are several instructables on building furnaces.

Raising enough temp to melt aluminum should be easy.

Gas + forced air provides a hotter flame. I have raised steel to white hot, (well above melting aluminum), with nothing more than a steel drum, filled with charcoal and air forced into the bottom.