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

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
-Charcoal
-Lighter

Comments

[flatcurve]

The slag is just the paint and PVC lining from the can (and crucible). Aluminum used in soda cans is actually very pure

[ajhbriggs]

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

[chirman23]

I agree but you dont get very much for one can and it is easier to find scrap aluminum.

[patlicky]

does this actually work?

[patlicky]

can i use barbewue heatbeads or barbeque fuel instead of charcoal?

[patlicky]

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 :)

[josh1324]

Can you just line the walls of the furnace (on the inside) with mud/clay to make the can last longer?

[curvy77]

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

[Wiredfey]

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??

[curvy77]

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.

[babeh2011]

Can I replace a soup can with a ceramic cup? Because as I know, ceramic can stand in extreme high temperature.

[the pro]

i don't know much about metal works but so why do you need the forced air?

[n0ukf]

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.

[nutsandbolts_64]

u mean the oxygen?

[n0ukf]

Yes, the oxygen is what makes it burn, but air is about 78% nitrogen and only 21% oxygen.

[nutsandbolts_64]

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 ? )

[strangebike]

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]

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]

where do you put the zinc carbon?
right into the fire where the charcoal is?

[Grey_valentine]

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.

[nutsandbolts_64]

just wondering if I can use this on ceramic foundries.

[strangebike]

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

[nutsandbolts_64]

wonder how you'll clean up the mess before it puts a black spot on the ground, haha:))

[n0ukf]

Pure O2 is very dangerous. Blacksmith forges use forced air (not pure O2) all the time to soften iron for working into the desired shapes. If you leave it in the forced-air fire too long, it starts melting/burning away. Just before you get to that point, the iron is just soft enough for forge welding.

[collard41]

if you use it on cold setting the air is denser, and therefore you can get more airin the furnace at once and it will burn MUCH hotter

[Killergunman]

Can u use wood vs coal?! plz respond asap

[Killergunman]

is there a hole in the bottom of the coffee can? it kinda looks like it and can this be build underground like in a sand environment?

[KyleHarima]

I would highly suggest not using galvanized metal on any surface of a forge. For I looked into the case of Paw Paw Wilson, who died heating galvanized metal.

[tomtortoise]

what if i am far away and hold my breath when getting close

[fragmaster4]

Just a safety precaution, Aluminum gives off harmful vapors when melted; Wear some kinda mask at the least.

[chirman23]

The coffee can will eventually burn away. If this is something that you are going to do many times I advise pouring refractory cement between the outer edge and the center where the crucible and coal is held.

[junits15]

what do you do with your aluminum?

[thepelton]

Lots of things you can do with the molten metal, such as casting.  When I was in high school, we melted some aluminum in a metal shop, and cast some small items by pouring it into molds carved in brick.  What occurred to me recently is that I was reading about soapstone, which is easier to carve than brick, and capable of standing a lot of heat.  It could be carved into molds in which to pour the molten aluminum.
8>)
Don

[thepelton]

You could put your mold in a box surrounded by an inert heavier-than-air gas such as Carbon Dioxide to stop oxidation.

[Notbob]

but wouldn't it start to oxidize as soon as it was taken out of the inert heavier-than-air gas and exposed to oxygen?

[thepelton]

Well, yes, but it would be slow, and incomplete, much like copper turning green, instead of fast, like burning wood.

[Notbob]

do you use anything to "grease" to muffin pan, or is sticking not a problem?

[thepelton]

Aluminum, when melted, is very oxygen hungry. Have you thought about how to prevent that?

[nanoassembler]

 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.

[nibbler125]

how do you keep the aluminum from mixing with oxygen and oxydising