Induction smelter for aluminum? - Page 1
Forum section: electronics / beginners

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: March 19, 2015, 04:43:46 pm
content: Does anyone know of a good way to make an induction smeltery/forge from some copper tubing, a 36v golf cart battery bank, and a steel criucible? My existing wood fired furnace keeps throwing embers and ashes everywhere and one landed in my glove. I would think that an induction heater would be much safer. Anyone got any designs for this? The batteries I am using are about 150Ah.

author: IanB
author_rank: Super Contributor
timestamp: March 19, 2015, 04:49:08 pm
content: Look on YouTube for any number of designs using a gas torch. It will be much cleaner than wood. But also, why not use charcoal?

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: March 19, 2015, 05:07:33 pm
content: Where I live, propane is too expensive. Also, the charcoal doesnt seem to last long enough. My fan is a hairdryer fan on 24v and it moves alot of air. The induction smelter seems like a neat project, becsuse I always overbuild things...

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 19, 2015, 05:29:52 pm
content: FWIW, "smelting" means "to purify or convert ore into metal". When it's already metal, you're just recycling / melting it.Induction isn't terribly hard to do, but to build anything more than a few hundred watt toy requires serious parts and engineering. I think John's working on the most likely candidate, as far as power * availability;http://www.johndearmond.com/2014/11/01/using-the-induction-heater-aluminum-casting/To really melt much of anything, you're looking at 3kW minimum; I'd say 10kW is where it really starts. Needless to say, you need enough electrical power available to begin with.The capital cost of an induction furnace is usually too much for the amateur to justify, at least for low-melting nonferrous metals (aluminum and bronze). Even with lots of hand made parts and discounting your labor to $0.00, you're looking at maybe $1000 of parts and equipment and months of work. It's a great project, for projects' sake, but not so great for the foundryman.If you're planning on doing a lot of cast iron and steel, the speed and efficiency gain may be worthwhile -- you might be looking at maybe $0.50 of electricity to do a few pounds of metal, whereas it might take hours and a pile of fuel to do it otherwise; and that's if you can achieve the temperature at all.As for fuels, back in the day when I was playing with this stuff -- I recall hardwood working surprisingly well. Briquette charcoal is crap, don't use it (it's ~20% slag, anyway). Lump charcoal is good, but don't buy it in any less than bulk; or make it yourself. Coal is good too, but hard to find by anything less than the traincar (local blacksmiths or groups may have some leads, though!).If you're having problems with cinders, I'd suggest a nice hat, leather coat, and maybe gloves (good for protecting the hand surfaces, but, the cuffs trap cinders, too!). Besides looking stylish,you'll save a lot of money over most of these options.Tim

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: March 20, 2015, 12:20:48 am
content: Quote from: T3sl4co1l on March 19, 2015, 05:29:52 pmThank you very much for the help! I tried my wood fired furnace again, but with the crucible mounted higher. This allowed hot embers to gather at the bottom, and I managed to melt about 50 cans worth of hardened aluminum that got stuck in the bottom. As for the induction, I imagined that my steel canister would absorb quite a bit of the energy, then thermally transfer it to the cans. but trying to get 10kw of power from my golf cart batteries would require parts that could handle 300+ amps. Not something I could do...