Would that be hot enough to melt aluminum?
Should manage aluminum without a problem. I wanted a waste oil burner, but here in Florida they're unheard of. You can also run diesel fuel in them, which should be able to hit cast iron temperatures. That's one of my goals, especially since I have an auto repair/scrapper less than a quarter mile from the house. I'm pretty sure I can obtain scrap cast iron there (old engine blocks). Scrap aluminum I get from work. I'm a Network and Systems Admin, so I get all the old and dead hard drives that I can handle. Got about 200 lbs worth of them to break down and cast into ingots (only have ~40 lbs of ingots left). Right now my furnace is small, and only handles about 5 lbs of aluminum or 15 lbs of brass/bronze per melt, but I'm on the lookout for a larger furnace body.
I did look at building a waste oil burner, but the convenience and compactness of the furnace burner is appealing. I may have to filter and pre-heat my waste motor oil (about 8-10 gallons on hand), but I don't think that'll be too big of a hassle. Right now, my furnace is propane fired with a 1/2" venturi type burner, and takes about 20 minutes to melt the first load, about 5 minutes or so per load after that. It's made from insulating refractory bricks, rated 2600F, and even after an hour and a half you can comfortably touch the outside. It does get hot enough to melt cast iron, but it's extravagant in propane costs, and *really* hard on the furnace interior. The spot where the burner hits the side of the furnace tangentially has seen better days. Once I find my bucket of castable refractory, I'll patch that spot.
I'll warn you, though. Casting metal is just as addictive as machining. Especially when you can cast and machine your own parts. Just be safe, contact with molten metal is a guaranteed trip to the ER. And probably a lengthy stay.
