Picture of Coffee Can Aluminum Foundry
Here I'll show you how to make a furnace for melting aluminum. The materials can be bought from Wal-Mart and your local hardware store. Cost to build furnace alone: $23 Cost of furnace and materials + tools to operate it: $50

*** 5/31/09 *** I will be making a new, revised charcoal foundry instructable as soon as I get some spare money. This setup is adequate, but there's always room for improvement.

Step 1: Materials and Tools

Picture of Materials and Tools
Required to build furnace...
-One normal sized coffee can (6")
-One hair dryer with a cool mode and preferably two speeds
-Duct Tape
-One 1.5" x 10" galvanized/black iron pipe nipple
-One soup can
-Tin snips

Required to operate furnace...
-Long tongs or pliers to grip crucible
-Steel spoon w/ holes in it
-Heavy leather work gloves
-Lighter Fluid
1-40 of 134Next »
fragmaster45 years ago
Just a safety precaution, Aluminum gives off harmful vapors when melted; Wear some kinda mask at the least.
Not really. Anyway they're much less harmful than the other vapors the whole process will be producing, so you really should only worry about that if you have fixed all the other odor problems first.
Unfortunately, fragmaster4 is right, but "some kinda mask" won't help significantly since those vapors will be heavy on ionized aluminum, unhindered by regular anti-dust masks.

What types of masks will be sufficient?

Ahnassi2 years ago
how much time the air blower will work before it overheats itself. is it enough to melt aluminium?

The longer the pipe nipple, the more removed from the heat and the longer it will last.

thepelton6 years ago
Aluminum, when melted, is very oxygen hungry. Have you thought about how to prevent that?
If you're going to use a steel soup can as a crucible, you could open the top with one of those newer can openers that cut the entire lid off. I would also put a steel nail through the lid to make the crucible lid a little heavier as well as creating a small handle for the trongs to grasp.
 You can minimize oxygen exposure by covering the crucible. It willlimit the aluminum's oxygen supply. Just use something that won't beblown off by the air going into (and coming out the top) of the furnace.

Caveat: Every time you open the lid, the aluminum's oxygen supply will be replenished.
Solution: If you have to melt a lot of aluminum, cut a hole in the lid large enough (but not to large) toadd more metal as it melts in the crucible. Some oxygen will still flowinto the crucible through the hole, but it will be much much less thanwithout a cover.
ScottB127 months ago

I see a flaw in this... If you use a "tin/steel" soup can... Aluminum melts at 1220 F, Tin on the other hand melts at 450 F (at least according to the details I've found, I haven't personally tested it, because I don't have any definitely tin cans.)

So unless you mean Tin-Steel alloy of some sort when you say "tin/steel soup can" a tin can would melt before you were up to temperature to melt aluminum.

I can't promise you won't have accidents, but if using a soup can, please make sure it is steel, not tin.

trask ScottB127 months ago

"Tin" cans are just what they're called. Due to the price of tin, these days "tin" cans are made from steel, sometimes with a tin coating inside for corrosion resistance, although now plastic coatings are often used,. If soup cans were made tin they would cost nearly $1.00. Tin is around 10x the price of aluminum and many times more costly than steel alloys.

ScottB12 trask7 months ago
The reason I bring this up is simple. Many people will build this as a hobbyist. The temperatures involved and the risks of mishaps are significant.

My comment was largely intended to alert the people trying to recreate this, that there are some serious dangers of they use a "tin/steel" can that turns out to be a tin can, the can will melt, while even using a steel can, the temperature might become hot enough to even make cheap steel risky. Some steel can become soft about 1000 F, while aluminum properly melts at over 1200 F. Some steel could breach before the aluminum melts.
sconner11 year ago
One could always sand or grind the zinc galvanizing off of the pipe nipple if you are worried about fumes.
I admit, Sometimes I weld galvanized parts together and can vouch that it is smelly and toxic.
Dust masks won't help.
It's better to not create the fumes in the first place, than to try not to breathe them.
Grinding the inside of even a short length of pipe poses a problem.
Looking harder or *Gasp* Asking for assistance finding the black pipe nipples may be the easiest fix. Or use copper which has an even higher melting point than steel.
Welders use copper "spoons" to back welds that are at risk of burning through.
patlicky3 years ago
can i use barbewue heatbeads or barbeque fuel instead of charcoal?
just buy a bag of charcoal, its not very expensive and it is just alot easyer.. or you could just make your own: http://www.instructables.com/id/How-to-Make-some-Charcoal/
babeh20113 years ago
Can I replace a soup can with a ceramic cup? Because as I know, ceramic can stand in extreme high temperature.
you will need make sure that the cup has no air pockets in it otherwise it will explode...
flatcurve6 years ago
The slag is just the paint and PVC lining from the can (and crucible). Aluminum used in soda cans is actually very pure
could you just sand the label off to reduce the "slag"?
the Aluminum in cans is very pure (though i'd believe that some oxidizes to slag as well)

BUT there are 3 very pure alloys: for the body, the top and the tab
each, separately, is high quality alloy- but melted together they make a much less useful metal

all those "recycled" aluminum cans we gather are actually "downcycled' in the worst sense of the word
-but with enough patience (or teamwork) you could take the tabs and tops separately, and use them for bicycles, airplanes and anything else aluminum your heart desires
I agree but you dont get very much for one can and it is easier to find scrap aluminum.
patlicky3 years ago
does this actually work?
patlicky3 years ago
does this actually work because i have tried alot of ways to make a furnace but none of those ways actually worked. So my question is does this awesome furnace actually work before i make it? Please reply :)
josh13244 years ago
Can you just line the walls of the furnace (on the inside) with mud/clay to make the can last longer?
mud would harden then flake eventully smothering the fire in dirt. clay could work however there is a chance of it cracking aprt. so be careful
Wiredfey3 years ago
Question, it's mentioned you use duct tape to hold the pipe on.anyone know if i'd be able to solder the pipe straight onto the hair dryer??
curvy773 years ago
thank you for your instructable! while i did not make the one u did it inspired me to begin my own forge. for mine was made of brick (not the BEST choice i admit but whatever) but i used your view in a small contained forge.
the pro7 years ago
i don't know much about metal works but so why do you need the forced air?
n0ukf the pro7 years ago
The forced air increases the heat of the fire, a forced draft rather than natural draft gives more combustion air to the fire. This is part of the same reason blacksmiths have blowers on their forges. As the coal cooks down to coke, it needs that draft air just to stay burning.
u mean the oxygen?
Yes, the oxygen is what makes it burn, but air is about 78% nitrogen and only 21% oxygen.
if someone here came up with a way to make pure oxygen, please make an instructable on it. It will help w/ the smelter ( can it melt iron by blasting pure O2 into the fire ? )
easiest way is to use hydrogen peroxide from the chemist (you use it to bleach your hair) and then add chopped liver as a catalyst to produce a lot of O2. the higher the vols the more gas produced. If my basic school chemistry is not in error!
2k4u (author)  strangebike6 years ago
While meat and H2O2 will produce some oxygen, it's a very small amount. I saw that experiment in a science fair book. It would never produce enough O2 to fill a balloon, much less help a fire. Common drug store hydrogen peroxide is a mere 3%, which is pretty bad for most experiments...If you have a barber/beauty license, you can get around 10% for bleaching hair...if you find the right chemical supplier, you can get gallons of 20% - 35% for cheap. One of the best chemical ways of making O2 is decomposition of H2O2 by adding MNO2, manganese dioxide. If you can't buy some from a chemical supplier, you can take it out of zinc-carbon battery. But for hobby scale metal melting, you don't need any oxygen. It would likely get too hot and burn up whatever your foundry is made of.
hard2bme 2k4u4 years ago
where do you put the zinc carbon?
right into the fire where the charcoal is?
You don't need a beauty license to buy it. I have my cosmetology license but have never needed it to buy anything, and a barber, well they aren't allowed to do any chemical services with their license anyway. A beauty supply store not affiliated with a salon would be your best bet to pick up a lot for cheap.
yeah I knew there was a another chemical based way but couldn't remember it. thank you for jogging my memory. You are probably right lots of oxygen is going to make one hell of a pool of slag on the floor lol he he
wonder how you'll clean up the mess before it puts a black spot on the ground, haha:))
just wondering if I can use this on ceramic foundries.
1-40 of 134Next »