Casting Aluminum Ingots

Introduction: Casting Aluminum Ingots

About: I enjoy building things more than actually using them.

I recently decided that I would try my hand at metal casting as a way to recycle aluminum cans. After doing some research, check out I found out the easiest way to get started would be melt some cans and pour them into a cup cake pan to make ingots. I can remelt them later once I figure out what I want to cast and get some more experience melting the cans down.

After looking at some of the furnaces here on Instructables I decided to make a decent crucible, the cup the metal melts in, and furnace from a paint can. I made the crucible from 3"OD x 1/4"thick steel tube with 1/4" steel plate on the bottom. I also made a special hooked handle to lift the crucible out of the furnace and and another hooked rod to pour the liquid aluminum out. I welded all of these parts together. For the furnace I just used a whole saw to put a hole in the lower side in the paint can. I used another steel tube, placed in the hole, as the blower tube. I bought a $10 hair dryer for a blower.

The basic idea is to put the crucible in the paint can and then fill the can with charcoal. Light the charcoal and let it get going, then turn on the blower to get things nice and hot. I used a paint can lid with seven 1/4" holes drilled in the top to keep the heat in the paint can while the crucible heats up. I also found that burying the can in the ground really helps to keep the heat in. The crucible needs to get red hot, which took about 15 min and a few charcoal reloads. Then start putting the cans in the crucible, about three at a time. Let them melt and then clean out the slag in the crucible. Slag is all the unwanted oxidized metal and ink used on the cans. I used a 1"x 1/8" piece of steel about 3ft long to get the slag out. Aluminum cans produce a lot of slag so I had to clean a lot. I poured standard table salt in the crucible which I read helps to separate the slag from the aluminum and makes the metal easier to pour. Once I melted all the cans I poured the aluminum into the cup cake pan, let them cool about 30min and was done.

If anyone have any ideas on what I should try to cast first I want to hear them.



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13 Discussions

Thanks for your guide. I'll definitely try it.


borax powder also works to separate slag if memory serves

You could cast an arrow head you could make a gel or sand mold and pour the aluminum in that


5 years ago

That is really cool!

try adding clean glass to your pre mix, it should float on top and prevent oxygen from reaching the aluminum. shreding your cans and tumbleing them in a cement mixer with brocken glass and detergent with water flowing through might help.

i have recently attempted aluminum casting and failed =(. however before i started i did make a chain of objects that can be made. first start out simple with a basic ring mould. then move on to more intricate molds. another possibility is to make braclet designs and sell them off with the rings to help support your forge. after that move up to bigger projects such as aluminum armor or helemts. maybe even a blade or two(wont last long or work well but can be deadly all the same.) while i canot cast i am a scrapsmith so i know how to find improper materials and change them into works of............well........i can change them.

You may have a problem using the aluminum from old soda cans. They are coated inside and this tends to contaminate the metal. also, if you overheat aluminum, it will absorb too much air and reduce the quality of your melt. Three (3) minutes after the aluminum melts, it is time to pour.

Good luck!

are you sure all that 'slag' is really slag? most aluminum is actually an alloy...... pure aluminum is almost never used for anything, as alloys present much better capabilities.

This is nice and all, but you should really turn this into a detailed instructable. I really liked both your instructables on vacuum formers and will probably build one soon! If you're still looking for something to cast, you should try making a lathe. Order the books on making your own metal shop from scrap from and that will give you ample detail. I have the first book, but I've been unable to find a five-gallon metal bucket that is perfectly cylindrical.

2 replies

I used this setup tonight and got a little over a pound of ingots. I ended up melting a little over 4 pounds of cans and got the 1 pound of ingots tonight. This was because as the charcoal turns to ash which just sits in the bottom of the can and doesn't allow the crucible to stay hot. This caused more slag which means less ingot. Realistically, I think this furnace set up could be good to melt about 2 to 3 pounds of cans at a time. Then the ash would need to be cleaned out after that, but thats only if the paint can has not burned though. So this set up is basically good for one time use, to melt at most 3 pounds of cans, that could yield an little over a pound worth of ingots. I don't think I'll end up making an instructable about this because I want to make a nicer furnace. When I do, I will do a full instructable. I've seen the stuff from gingery before, but I think I want to do some simple things first. Then if I get really ambitious I might try my hand at a home brew CNC machine, but with cast parts.