Picture of Quick and cheap aluminum melting furnace setup
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This Instructable shows a quick and cheap setup to melt a few batches of aluminum for casting before the thin metal equipment starts to break down. Actually the 5-gallon bucket furnace will last quite a long time, over a dozen uses easily. This uses BBQ charcoal as the fuel and a hair dryer as the blower, it'll melt a small batch of aluminum in about 10 minutes. Most of the materials to build this can be found in dumpsters; the only cost here is the charcoal fuel, duct tape, and the $1 yard sale hair dryer. Recycle old lawnmower parts, computer/stereo parts, and beer and soda cans to make awesome new things with them.

For the furnace, two five gallon metal buckets (with lids) were used, a piece of 3-inch stove pipe, hair dryer, and of course, some duct tape.

For a crucible (the little bucket that holds the melted metal), a 16 oz propane bottle was used; the top was cut off and some bolts were added for grabbing the crucible with the tongs.

I made some basic tools with some scrap steel from an old bed box spring. You'll need tongs for the crucible, some kind of shepard's hook to tip the crucible when pouring, and a plain rod with a little bend at the tip for poking things and skimming out the dross (impurities in the aluminum).

Use of this equipment shown is dangerous because of very high temperature molten metal, fumes and smoke, etc. Use caution and be safe by wearing leather gloves, face protection, and other protective clothing. Do this outdoors and use it when it's a little windy so the smoke and fumes quickly dissipate, also use this during dry conditions because dripping molten metal on wet surfaces can cause little hot metal explosions (like water and hot oil in the kitchen). I'm not liable for any injuries you may occur using the equipment and techniques shown here.

Read, read, read lots of metal casting stuff before starting.

Casting Aluminum at submarineboat.com
Home Foundry
BackyardMetalcasting.com ...Melting and casting metal yourself

Here's a silent movie of the foundry at work.
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TomOlsen1 year ago

You can make a longer lasting backyard foundry using a metal trashcan (I think it is about 20 gallons) for an outer wall, a metal 5 gallon bucket for the inner chamber, cheap unscented Kitty Litter (it is made of clay) to fill gap between outer wall and inner chamber (mix with water so it will pour like concrete, let dry thoroughly before using), some pipes and a blower for forced air, and an empty propane torch canister (make sure it is totally empty, fill with water & empty before cutting it to use as your crucible!), and charcoal as your fuel. You can scale this down, use the 5gal bucket as outer wall, large coffee can as inner wall. Just remember: Injuries from molten metal are PERMANENT! Molten aluminum can burn right through normal clothing and through your leg. So, BE CAREFUL! Do some Practice runs using sand as your "molten metal" so you are not surprised by the weights.

robbtoberfest (author)  TomOlsen1 year ago

Thanks for the awesome tip!!! I will be building a new one soon.

afridave8 days ago

can plaster of paris mould be used to cast this moulten aluminium into?.....i would imagine they would deteriorate rapidly due to the heat...anyone know any adjuncts to add to plaster of paris to increase its heat resistance/durability....oh and if you try using plaster of paris make sure it is well and truely dry.....kaboom otherwise

WhiteP11 months ago

okay, once the aluminum is melted.. what can I pour it into for a bar shape?..that will put up with heat and keep its shape.. and I need to know a little on the cooling process, as in when it's safe to grab and such.

JessV1 WhiteP5 months ago

Well then. You'd just get steel or something else with higher melting temperatures. Typically you see people just using a stock bar imprint of steel or little nugget molds.

How can I make a furnace to work on a larger scale? I am talking about having enough aluminum for large projects ( at least 16"x20"x18") but some projects are larger. The small one just won't last long enough or melt enough metal at a time.

That's a lot of aluminum, make sure your furnace is actually hot enough to make sure the center of the aluminum is as hot as the edges! Suggestions to break a larger project into smaller ones would be making aluminum chunks that fit into each other through a series of tight bars and meshes. Or when you cast them you can add a center to your mold so the aluminum makes a thick shell around the outside (your required strength) but you save tall the aluminum that would've been in the center.

WhiteP11 months ago

and what did you use for the bolts on the old camping propane tank, and how did you cut it open.


jj.inc4 years ago
I want to use a clay mold and make a sword prop, but aluminum isn't strong enough on its own, do you have any recommendations for other metals to add.
Also could I use crushed pop cans, trust me I have enough.
Copper. Aluminum bronze is very srong
Personally, i would recommend a 15% copper (Pennys or Cents), 10% steel (if not available, stainless steel old cutlery or 10% zinc) and 75% Aluminium (cans of pop)

This should create a stronger metal mix.
I wouldn't recommend it but i suppose you could add 5% gold.
(I get my gold by panning in North Wales, UK)
I am not sure if I should take you seriously because I don't think steel and aluminum alloy together well.
crazypj jj.inc1 year ago
Aluminium will dissolve stainless steel, even though it melts about 1,800 degrees lower temperature
Stainless is good when your scratching surface of aluminium to remove oxides but if you try and weld the stainless will bond extremely well I'm guessing you won't need to ask how I know ;)
Do you mix by volume or weight when making alloys?
Well... i think it depends but i was told you mix by volume as mixing by weight may not be accurate as the material may be lightweight
Add zinc to it to form a Zamak alloy.
Though you'll need to look up what the exact proportions and stuff are for the best blend. Also, doing it this way you will only need about 600 degrees, while raw aluminum only melts at a thousand-some degrees.
robbtoberfest (author)  jj.inc4 years ago
You'll need a stronger furnace to go hotter and use some other metal like steel. Pop cans are aluminum.
Yea, I should have re-ordered it, I meant I could use the pop-cans for the aluminum. Steel is expensive, do you think it would mix with the aluminum in a hotter furnace. Maybe add the steel once the aluminum has melted using an oxyacetylene torch (hot metal cutting torch, will probably boil metal
@jj.inc: Maybe you could use a piece of small diameter re-bar as the center of your mold piece. Maybe make it out of wax around a rebar core, and pour the AL down in the mold. The AL might form around the steel core, gripping the ridges on the rebar.

That would give you strength.
robbtoberfest (author)  jj.inc4 years ago
Dude, that's way over my head; you're getting into the world of metallurgy and need the advice of skilled people for that. Mixing metals is tricky work.
Aluminum and steel will not bond with each other. Melting temperature is far greater for steel, not to mention, you would be melting the crucible in the process as well. You should try casting with just the aluminium, you will problably be surprised how strong it is. Other than that, creating an aluminum alloy would be unpractical, expensive, and highly inefficient., rather than buying the prop.
immy0072 years ago
Hey Guys
I wanna manufacture Air condition aluminium grills by melting and moulding the the grills shape can any one help
justicious3 years ago
I read on another forum that the aluminum will get stuck to the muffin tin is this true?
I like this instructable a lot; practical, easy, cheap...up and running in no time. With a bounty of discarded scrap people regularly throw away (found a perfectly good, heavy aluminum CO2 cylinder today!), this is virtually a free hobby. More info on mold-making would be very useful; though I'm sure there's plenty out there. Thanks for doing this.
patlicky3 years ago
oes this actually work before i make it?
robbtoberfest (author)  patlicky3 years ago
Yep; its a very low-effort build for melting aluminum.
sinkerman3 years ago
the little red hand held dirt devil vac's make a good blower . can be got at yard sales cheap . broken belts don't matter . you can use a cut down 30 gl drum and the 5gl bucket inside with mortaland firebricks inbetween for instulation will heat faster and hold the heat . make yourself a set of arm sleeves from a old pair of boys jeans cut off leggs and wear onyour arms for protection from heat and splashing molten metal
robbtoberfest (author)  sinkerman3 years ago
Nice tips, thanks. The firebricks are a good addition; this design loses heat rapidly.
andygreene3 years ago
Don't use any galvanized metal for making any of your foundry tools or equipment. When heated or melted, it can give off toxic fumes. Very very bad.

Awesome instructable, along with your tile making dye/stamps! You rock!
corkey1234 years ago
NICE! Just what I needed. Thanks!
arirang7776 years ago
okay, how did you get the mini "propane" camping tank opened up? Obviously it was empty, but still it may be a hazard to use a saw to open it. What's your trick? Thanks in advance!
most of the small tanks have a valve that you can depress letting all the excess propane out... similar to a valve in a tire.
robbtoberfest (author)  arirang7776 years ago
I put the tank in a vise and used a hack saw, no sparks or anything. Beware of the residual propane stink.
How did you attach the bolts to the crucible? I'm not very wielder savvy..
robbtoberfest (author)  Firestorm_1014 years ago
Drill holes in the side of the pot and just put the bolts in there with nuts.
knektek4 years ago
W00T! My DT teacher was like this stuff needs to be shipped all over the world just to be metled. And cuz he's long he went on about the gulf of mexico oil spillage....
If you read the entire instructable (like you should) then you might have noticed the first sentence he says in part 4 is and i quote "wear leather gloves"
nicolo865 years ago
How much aluinium a beer can gets you. Great instructables !!
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