Melt Aluminum for $3 and some begging!

Step 1: Begging and Buying

The Sauce Can Foundry

This is a really fun project that doesnt take much time at all and once completed enables you to melt metal!

::Warning::This activity does involve fire and very high temperatures, so bring your common sense and competence along. You should engage in metal melting activities fully covered, wear leather boots, jeans, and a long sleeve shirt. Use eye protection and gloves over your hands.

- 2 used Papa Johns sauce cans (just walk in and ask for a couple, early morning or early afternoon is usually when they prep sauce)
- 1 used bean can
- 4 inch diameter x 24 inch length Galvanized Oven Vent
- Blower with a power source
- A few screws or rivets
- Foundry stand (jackstands and a grate in my case)

- Can opener
- Flathead Screwdriver
- Drill with proper bits
- Sheet metal bender (in my version)
- Tin Snips (scissors might get it done too)
- Hammer
- Sharpie
- Clamps
- Pliers

- Charcoal
- Cans or other forms of aluminum
- Welding Gloves
- Lighter Fluid (optional)
- Tongs or a coat hanger for holding the crucible
- Spoon with extended handle for dross Removal
- Eye Protection
- Somewhere to put the molten metal, I used a muffin tin.

If there's something in this list that you dont have or cant get then try and improvise (except on the safety stuff). The first time I made one of these furnaces the duct was made from left over rain gutters. And the blower came out of a microwave. Just give it a little thought and start building and see what you can come up with.

Step 2: The Duct

Next we will prepare the duct.

Wrap a piece of paper around the stove pipe, line up one edge even all the way around. Then grab the sharpie and mark a line all the way around the duct. This needs to be about a foot from the sharp edge of the duct (to make about a nine inch to one foot long duct)


Then pop open the seam of the duct, take your snips out, and cut it along the line.


Next we have to deform it into a rectangular shape, this is alot easier than it looks.

Take the duct in your hand and press it against a hard flat surface (your table) it will form 2 seams approximately equidistant from each other


Then grab the duct about an inch or two from the one of the creases and press it against the table again making another crease.


Now press the wide flat part of the duct against the table, holding it approximately the same distance as the other shorter face and bend in the last crease.



The duct is finished, now for the Can....

Step 3: The Can

First your gonna need a helper...
Or alternatively some clamps :]
Clamp the can down, get out your hammer and screwdriver (i guess a chisel would work too). Place the screwdriver towards the bottom of the can about as far from the bottom as you duct is tall. Start pounding the screwdriver in across the circumfrence of the can, making a hole big enough for your snips to go in.


Once your snips can be inserted start cutting away at the can, be careful not to be too zealous and cut it too big. But you want a hole not quite as wide as your duct and just about as tall.

Step 4: The Adapter

This is the hard step.

In this step we have to adapt the blower to the duct size.

This is the step that will require you to adapt to the blower you picked out, mine was an A/C Fan from an 86 honda crx. :)

The way that I made the adapter, I took the blower and sat it on my sheet metal and tried to trace around the outlet (you can see how well that went). Then I trace inside that around my duct.

Then I used a straight edge to draw in some flaps on the inside (duct) and the outside (blower), in order to rivet the adapter to the duct and tape it to the blower.

Step 5: Diverter and Grate

Now we just need a diverter and a grate to get the air into the combustion chamber.

The diverter should be made from some of the left over duct sheet metal. trace the outline of the can, then add about a 3/4in flap to one side. Cut this shape out, and bend out the flap. It will have to be adijusted till it just fits in the can. Just cut off a little at a time with your snips till it just slides down into the bottom of the can.

Then bend the first 2 inches or so opposite the flap, the purpose of this piece is to ramp the air into the furnace, so it should look like a ramp.

Next we need a grate.

Take the second salvaged can, and a phillips head screwdriver, and you hammer. Place the screwdriver on the bottom of the second can and hit it with the hammer till it pops through...

Continue until the bottom is riddled with a nearly even distribution of holes.

Now cut out the bottom out with a can opener.

Step 6: Mating

After this step you will have a device that vaguely resembles something not useless.

First we need to prepare a place for the grate. Take out your drill, and drill a few (3-4) holes around the circumference of the can about half an inch above where you cut the hole for the duct. Screw in a few short screws, these are for the grate to rest on.

Now we need to modify the duct so it can be riveted or screwed onto the can. Use the can to mark an arc line on the wider side of the duct opposite the seam. Then add two more lines perpendicular to the edge for a flap. (see picture below) After cutting along these lines bend the flap out perpendicular to the duct.


Then cut two flaps out of the sides of the hole that you cut in the can for the duct, and bend them both out too.

Drill through the top flap and the two side ones, through both the can and the duct. Put the flap on the top side of the duct inside the can. Place the holes together and insert a pop rivet, or screw.


You can now place the grate down inside the can, resting on the screws...

Then you need to stick the adapter and the other end of the duct together. Doing this is very similar to the other end of the duct. Just drill a hole through each flap and place a rivet or a screw through it.

That's it :D
Just tape the adapter to the blower and your done.

Kick back and view your handiwork.

Step 7: Preparations...

Ready to fire it up?
Your going to need some supplies first.
Get some gloves, charcoal, Tongs (or other crucible holder), a spoon, a lighter, and some lighter fluid.

The tongs, the spoon and the Crucible need to be slightly modified.

We'll do the tongs first. Clamp them into your vise and take some pliers and bend out the end. After its bent out some take them out of the vise and place the very end in the vise and clamp down, we want them straight out to the end. After they are straight clamp them in the vise again with about 3/4 of an inch protruding out of the vise. Take a hammer and whack the protruding end till it is flush with the vise surface. Do this to both sides of the tongs.

That makes a handy crucible holder.

Now take the spoon and mate it with tape to some long object (like an aluminum pipe in my example). I tried to use the spoon as it was and my hands got QUITE toasty, within my gloves.

Now for the crucible, you simply need to drill or poke two holes in the top of the can (the crucible is a bean can). The holes need to be big enough to recieve the crucible holder.

Next test your blower and power source to make sure air is coming through the duct and into the furnace.

Once everything is ready, its time to burn!

Step 8: The Burn

Make sure you have your furnace in a good place where it cant catch anything on fire, a concrete slab or sand area is best, with no trees or other vegetation too nearby (10ft or so), ashes are going to be flying in the air so make sure you arent gonna catch anything on fire.

I place mine on a barbecue grate held off the ground by jack stands, on a concrete slab.

First we need to line the furnace with charcoal. Place the crucible on top of the bottom layer so subsequent briquettes can be placed around the inside of the furnace.

Douse the briquettes well in lighter fluid, then light them....

Making a device that contains fire gives a different feeling from just about anything else. It is beautiful. :D

Let the charcoal burn for about 5-15min and get good and started, you dont want to have to relight it.

After it is going good, turn on the power. Within a minute or two all the metal around the charcoal should be glowing red.

Now start placing aluminum in the crucible, make sure to use your gloves and tongs (hold the cans/etc over the crucible and drop them in) and eye protection.

Cans are fairly low grade aluminum something better would be preferred, like broken castings or overly painted welded aluminum joints (from high class lawn furniture). Most things are gonna flame up and put on a great show when they go in the fire. This part really is fun, for all its danger.

Step 9: The Pour

Well now we've melted aluminum, but what can you do with it?

Well, if you know how to pour a casting that would be a really great thing to do with it. I dont, so I just poured it into an ingot. Later, when I learn how to cast a part then I can melt the ingot down (free of dross), and make it into something.

So first we need to remove as much material that is not aluminum as possible. Aluminum will be a shiny, shiny liquid at the bottom of the crucible, the dross will be anything floating on top of it.

Grab the spoon and jam it into the crucible (carefully), you should be able to see/feel what is liquid and what is not, remove as much of what is not as possible. Likely you'll come out like me, after sticking it down there once and bringing a wad of gunk out, the wad as well as some aluminum was stuck to the spoon.

But thats good enough...

Now we need to pour, first turn off your blower, then just place the ends of your crucible holder into the holes in the crucible CAREFULLY!! You REALLY have the chance to severly hurt yourself here!! Lift the crucible carefully out of the furnace. It will virtually instantly make crackling and popping sounds of very rapidly cooling down. I hope your cast was nearby...

Use the spoon in your other hand to gently lift the bottom of the crucible, pouring out the aluminum below the remaining dross.

WOW!! Look at that shiny stuff, isnt that amazing!

It will QUICKLY become dull and begin to solidify, and the muffin tin (if your using one) will become dull red .

Let it cool upwards of an hour before trying to touch it.

After pouring, place the crucible back in the furnace, and let everything die down and cool. Your charcoal should still be burning and everything will be hot for several hours, try to just let them be.

If you have some marshmallows break them out, and roast them over the remaining fire (might as well).

Congratulations, you can now make liquid metal, and form it into things. The whole world is open before you (or at least it feels that way).

How do you get the ingots out of the tin? I have six that seem rather stuck.
awesome man, i want to build one now
Awesome idea, what other types of metal can you melt?
with that type of furnace, you can melt any metal that melts under 700&deg;C but it's better for a beginner to stay with aluminum because some metals, like zinc and magnesium, can be very dangerous to melt(zinc fumes disease, magnesium fire at over 3000&deg;C).<br />
I built forge after seeing this instructable, but instead of the pizza can I used bricks, and instead of the bean can I used a crucible from <a rel="nofollow" href="http://budgetcastingsupply.com/">http://budgetcastingsupply.com/</a>. I also used a shop vac as some comments have suggested. I liked the construction of the duct here, and used it as a starting point for mine.<br/><br/>Overall, I think this instructable is a great introduction to 'forgery'<br/>
What can you use melted aluminum for?
Do the alumium cakes make your fillings hurt like foil does, or do you just eat them anyway?
I'm sorry... what? i just don't quite understand your question. you dont eat metal. it poisons you (heavy metal poisoning). and what aluminum cakes are you referring to?
hes joking
could you use a 12 volt plastic computer fan for the blower?
I dont think it would have enough flow. But I dont know how much this A/C fan has. Give it a try and tell us if it melted the metal.
Alright, I'll try when I have time. :D
Cool! Is it possible you could make a lantern-battery-powered carbon arc furnace?
this is similar to one i made out of a piant can and a shop vac that i reversed =]melts good <br/>
thats awesome :-) but, how is the can not melting, but yet the inner metal is ? even if its the same metals ( aluminum can, w aluminum can shards for melting?)
The Crucible can is made of Tin (or should I say steel), and it has a hotter melting point, but it did get hot enough to glow red. The Crucible can is certainly the weak point in this setup. I'm sure the can's inner coatings contaminated the aluminum. For actually casting things (which I will get around to one day), you would need a better crucible before you needed to improve anything else.
hmm. ok, well i want to build this to melt metal, and i would be using a can probably a small coffee can or a x-large bean can, and i would be wanting to melt steel, aluminum, or mixes in the can would that work? :-\. i really dont know how to explain what im trying to say, like if you had an aluminum can you could only melt aluminum, and if you had a steel can you could melt anything up to steel (melting point) and if you had a steel can with melting steel it wouldnt melt through? Sry for all these questions, but hey if you melt metal you want to make sure it does not go through and cause a river of molten metal to spew all over your stuff :-X!
Ok, here's a little chart of melting points from lowest to highest<br/>Metal Name Melting Temperature F&Acirc;&deg;<br/>Tin 450<br/>Lead 621<br/>Aluminum 1218<br/>Magnesium 1240<br/>Bronze Cu+Sn 1562<br/>Brass Cu+Zn 1652<br/>Silver 1762<br/>Gold 1946<br/>Copper 1981<br/>Cast Iron 2300<br/>Steel-High Carbon 2500<br/>Stainless Steel 2550<br/>Medium Carbon 2600<br/>Nickel 2646<br/>Low Carbon 2700<br/>Titanium 3263<br/>Iron 2786<br/>Chromium 3034<br/>Tungsten 5432<br/>Carbon 6512<br/><br/>I stole it from <a rel="nofollow" href="http://www.muggyweld.com/melting.html">Here</a>Here. As you can see aluminum <br/><br/>melts at only 1200 degrees . (After finishing this I had to make sure that cans were made <br/><br/>of steel, wikipedia was ambiguous about it and several other sites so I took a magnet after <br/><br/>some cans we have here) <br/><br/>Most bean cans are made of steel with an inside tin coating (After finishing the above <br/><br/>chart, I had to make sure that cans were made of steel, wikipedia was ambiguous about it <br/><br/>and several other sites. So I took a magnet after some cans we have here, it is steel). So <br/><br/>its melting point is Approx. 2500 degrees (high carbon steel). So the furnace produces <br/><br/>somewhere between 1200 and 2500 degrees Fahrenheit, because the can doesnt melt. <br/><br/>To make an uncontaminated melt your gonna need a better <a rel="nofollow" href="http://en.wikipedia.org/wiki/Crucible">crucible</a>crucible. There are quite a few ideas for building a crucible from things laying around, all available with a quick google search. :P<br/><a rel="nofollow" href="http://ezinearticles.com/?Building-A-Hobby-Crucible-Furnace&id=153129">Heres one for example</a>Heres one for example ....<br/>
I have a similar set up and my steal can did melt. or to be more accurate the hot aluminum slowly leached through the can till I had holes.
hmm...i thought the melting point of aluminum was ~900.... o well. Great project, when i get the time, i will have to try this! =D<br/>
hi aluminum melts at 660 degrees Celsius you might be thinking of silver thats 960 degrees Celsius the chart above is in Fahrenheit
:-) thanks
hello i think i can help you with that if you would like to melt aluminum you could use a steel pot or can but stuff like copper brass bronze iron needs a ceramic crucible becuse these metals would disove the can crucible and that is realy dangerous one day i would like to put an instuctable on this subject and building a propper furnace. chhers
Gingery! GINGERY! GIIIIIIINNNNGEEERRRRYYYYYYYYY!<br/><a rel="nofollow" href="http://lindsaybks.com/dgjp/djgbk/cruc/index.html">make your own crucibles.</a> there's also a bunch of fun kid stuff, like science project ideas, and a couple big books of all the crazy science stuff that <em>didn't</em> work through history. its pretty cool if you don't already know about it.<br/>
nice rendition. mine uses an old hair drier and some tube for air supply.
when you melt the ingot down later, it wont be free of slag. that is the oxides forming form the extremely high temps as well as simple air exposure.
Um first of all, you didn't really mention anything about your blower = ( sad face...<br/>Second of all, like the guy below asked, the pizza sauce can will eventually start to melt/deteriorate from the high temperature. Correct me if im wrong, but if you have used it a couple of times you are probably noticing that. Just from my own personal experience, soup cans that i used as crucibles started to fall apart after like two uses.<br/>
so is this good if you just want to heat up metals too, but you put them in for less time? Also... The can doesn't get melted at all does it?(the one holding the coal)
nice forge, i got a suggestion you can use an air compressor instead of the blower thats what i use, it works great and higher pressure = hotter flame <br/>
what happens if you heat up a cender block up to the temperature that melts aluminm? does it explode like river rocks in a fire (which is cool until you look down at arm and find shrades of rock and blood, not cool >:(
dude thanks this is a great forge and cheap too.
Another source of good crucibles and crucible related information is Budget Casting Supplies:(http://www.budgetcastingsupply.com/Crucibles.php)<br/>And with free shipping it usually works out fairly economical!<br/>
anyone know if you can have too strong of a fan? i have an old central AC fan that puts out some major thrust. would it put out the fire or would it help?
yes the fan can be too strong if there is too much air then you would get what is colled an oxidizing fire kind of the same as a cutting torch you want a reducing fire {just too little air for perfect combustion} and that olsow help to reduce the oxidation of the metal
If the fan blows too much air, it will melt the steel can. I use a blow drier (the kind used for hair) on low to melt metal. It doesn't take much air. :) stoobers@gmail.com stoobers.googlepages.com (my projects!)
You could regulate the speed with a variable transformer like a varistat or you could restrict the air going in the fan which would reduce the air flow. Have you thought about a scrap hair drier gun (lo-hi) ??
It MIGHT work, but most likely, it'll blow your coals straight out of the firepot. If you're slightly less unlucky, it'll mearly bring your coals upto a temp high enough to melt/seriously soften your tin-can crucible. Adding a hole in your ductwork, and a varible cover, you can make your own "airflow gate" to use the big fan. To give you an idea, I have used a shopvac exhaust to drive a coal powered IRON furnace. yes. MOLTEN IRON! That's probably less airflow than yoiur AC fan.
you can try you really dont want fire u want hot coals
Well I'm not sure but I don't think so,but a too big fan can blow away too much heat. Think of it as a heatsink,the faster the air goes,the cooler it is.
Most likely, yeah. If you had a really big furnace it would work great though. :)
check out the Gingery books from lindsaybks.com. build furnaces, crucibles, blowers, etc for very low prices.their book Building a Gas-Fired crucible Furnace shows how to build a furnace, gas supply, crucible, crucible tongs, blower, etc. oh, and it melts iron.
Really nice Instructable,thanks! I think a more substantial crucible would be a used steel disposable propane bottle that's cut to size. Also I loved the suggestions by others especially about the foam/plaster mold technique. I have an old motorcycle that the sissybar/luggage rack is no longer available for,I'm going to try to make them,as used parts are rare and costly.
Great instructable, I would recommend not using metal at all as the crucible and juat using one of those really small teracotta plant pots. Or just invest in a proper ceramic one, it's probably worth it if you are going to be using this regularly/seriously Otherwise, great use of materials and will start asap.
About how long does the Al take to melt?
hmm, perhaps an alternative would be to use a dremel tool with a cutoff wheel attachment, then deburr and sand the edges, or use tin snips if you have a fine touch. i dunno though; just putting my 2 cents in
This thing looks awesome! I'm going to have to start gathering parts, I've been contemplating building a furnace/forge for a while, now that I've got my lathe I might as well build it. Just one question to make sure I have the theory down, the coals provide the heat, and blower provides the air that makes the coals hotter correct? Basically what I'm getting at, it's just a system for blowing air past the hot coals? Theres no propane or any such things? Also, how much charcoal do you burn through usually?
Yes, it is basically a system to blow air past hot coals making them burn hotter, and consequently faster. When I did a burn I filled the furnace the first time, then I think I filled it 1-1/2 more times, which to me seemed about the same amount of charcoal as cooking on my barbecue. :) (about half of a smaller bag) The response to this project has been more than I ever expected , but it would be really great to see someone else attempt to build it. It's really not that hard at all, just very dangerous.
The whole setup seems very nice and easy to run, as well as cheap. Not as much as propane, and though a waste oil burning furnace/forge would be nice, it's more complicated than yours. Weather sucks and it's Christmas, but when everything improves I'll work on building it and post my results. Thanks for the reply and the great instructable!
sweet god...ive been looking to make cheapo arrowheads...thanx +1
Wow, never thought of that. That's a perfect application of this setup. :D

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