Introduction: Low Cost Aluminum Foundary

Picture of Low Cost Aluminum Foundary

One day I went to a party and saw that a hefty amount of aluminum soda cans were being thrown in the trash bin. I wondered and decided to repurpose these cans into small Aluminum "Muffin" Ingots for casting.

***DISCLAIMER*** Liquid aluminum is over 660 Celsius so use all precautionary measures. Long pants/sleeves, resperator, heat gloves, face shield, etc.

Step 1: Gather Your Materials

Picture of Gather Your Materials


Backyard Grill Charcoal Chimney Starter

Unica Stainless Steel Cup (18 oz.)

2 in. x 2 ft. PVC-PW Sch. 40 DWV Pipe

2 in. PVC DWV 90 Degree Hub x Hub Elbow

Style by Revlon 1875 Watt Dryer

Backyard Grill Deluxe Stainless Steel Grilling Tongs

Backyard Grill Briquets, 8.3 lbs

MainStays 12-Cup Cupcake Pan

Masking Tape

All of these items can be found at Home Depot and Walmart for insanely cheap prices.

Step 2: Connect the PVC to the Elbow

Picture of Connect the PVC to the Elbow

If you purchased the right parts. The PVC Pipe should slip right in with the PVC Elbow for a tight lock. After that just slip it in to the opening you created in the perimeter and match up with the center bricks.

Step 3: Create a Safe Brick Perimeter

Picture of Create a Safe Brick Perimeter

I had some old bricks lying around the backyard so i used them as a do not cross visual and also if an accident were to occur around the foundary, the bricks would prevent spreading. I put 6" of clearance frome each side of the center bricks and an opening for the pvc pipe to slip in.

Step 4:

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Now Tape the cool button down on your Revlon and slip it in to the end of the PVC Pipe away from the brick perimeter.

Step 5: Placing the Foundary Body

Picture of Placing the Foundary Body

Now that you have your brick perimeter set up and the pipe is centered, set bricks to elevate and place the Charcoal Chimney Starter centered with the Bicks and the PVC Elbow.

Step 6: Placing Charcoal

Picture of Placing Charcoal

Set down some paper and douse them in charcoal lighter fluid, also coat the charcoal as well. This will ensure that the charcoal will light and burn efficiently.

Step 7: Placing Crucible

Picture of Placing Crucible

Before lighting the fire, place the stainless steel cup (crucible) into the center of the furnace. Place charcoals around the rim of the cup to ensure leveled heating. After everything is set light the charcoal and wait for the charcoal to be at a steady burn.

Step 8: Applying Air

Picture of Applying Air

Once the charcoal is at a steady burn, turn the Revlon on to the low setting making sure the cool setting is taped down. Wait 2-5min before adding cans.

Step 9: Smelting and Pouring

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Place cans and push down until they are melted. Be sure to scoop up the impurities and slag the cans produce. When you have enough aluminum in the crucible, pick up the crucible with your stainless steel tongs with a firm grip and pour into muffin pan. Be sure to throw the aluminum "muffin" into a bucket of water as it is still very hot when it solidifies.

Step 10: Aluminum Ingot

Picture of Aluminum Ingot

Now that the aluminum is cooled, you can either show it off or melt a couple cupcakes down for some sand casting projects!


dhymers (author)2015-05-17

I made a similar version and melted through 2 stainless crucibles, one identical to the one used. Looks like an ss cup is good for one pour with perhaps 8-10 cans of alu, i think once you reach beyond that the steel fails. Going to look for a proper crucible, the rest of the setup works great, beware, this thing will eat a whole bag of charcoal.

snowdrop1101 (author)dhymers2016-05-25

I use half of an old fire extinguisher and it looks just as good as when I cut it in half. Simply take an old fire extinguisher (preferably A small one) and cut it half with A hacksaw. It works great!

Izzypup (author)2016-01-07

Have you ever sanded the colors off the cans? That's one less impurity - or is it easier (and less time consuming!) to get rid of it after the cans are melted?
LOVED this 'ible! I think I just might be able to replicate your process! Thanks!

diybomber834 (author)2016-01-06

couldn't you just use grease and make a crucible holder? just wondering.

TheNotoriousHoppington (author)2016-01-04

My PVC ended up melting, so I got some galvanized steel pipe instead. However, the largest size I could get was 1 1/4, so the airflow was greatly reduced. Any suggestions?

Sletten7 (author)2015-11-15

Be careful I got that same steel cup and put some holes in it because my foundry got too hot

jr_hobbs (author)2015-05-19

Wouldn't it melt the PVC?

gustavio101 made it! (author)2015-04-15

I made a simular one but i used concrete and made a top aswell.

yehyarocks (author)gustavio1012015-04-20

Looks great!

gustavio101 (author)yehyarocks2015-04-20

thanks, but as you can see the concrete top cracked :(

dhymers (author)gustavio1012015-05-17

Stuff in a rebar triangle next time, pour half, drop in 3 bars, pour the rest :)

Jobar007 (author)2015-03-31

Just so you know, most compressed charcoals like the above contain a relatively high level of sulfur. It is released at the high temperatures of burning charcoal (actually much less, but we won't get into that). That liquified sulfur does get into your aluminum and can influence how it casts. I can't remember off hand, but I do remember it isn't good.

This is an easily accessible means to wet your feet with aluminum casting. I would recommend insulating that charcoal starter with some rock wool if you can find it to improve your effenciecy.

yehyarocks (author)Jobar0072015-03-31

Thank you for your input! I did not know the sulfer levels in the charcoal could change the structure of the cast. I will use your advice and better this project in the future. I'm only 15 so I'll be learning all the chemistry aspects next year. Thank You!

weish (author)yehyarocks2015-04-02

sulfur and phosphorus(and copper, when you're talking about steel welding) tend to affect the properties of the metal when you're smelting, casting or blacksmithing. the reason blacksmiths use low sulfur coal is that contamination of those trace elements can cause brittleness, weak welds, increased vulnerability to corrosion, and a whole mess of other issues. luckily these days we have the whole internet available to us for information and guidance so that we don't have to learn these things the hard way anymore.

that said, great instructable, it's an excellent way for someone to get their feet wet if they're interested in metal casting. I hope you stick with it because this is a promising start and shows cleverness and creativity.

david.lister.1671 (author)weish2015-04-02

Are you sure that is relevant in this case Welsh?

A smith puts his metal directly into the charcoal, so the chemical content of the charcoal can effect the metal. In this case the metal is not in contact with the charcoal. It is sitting inside a stainless steel crucible. Any sulphur and any other chemical vapour will rise and go past the crucible so i don't see how it could effect the molten metal inside.

weish (author)david.lister.16712015-04-03

it can definitely be a factor. the metal in the crucible still has one surface exposed to the air inside the furnace. this is why for sensitive, easily oxidized metals like copper you want to have some sort of protective layer(such as crushed charcoal or molten flux) floating on top during the melt. an extremely hot reducing flame, in concert with a good flux, can even be used to reclaim oxidized metals for casting, such as copper that's been polluted by oxygen absorption during a previous melt. done right, you can convert rusted iron or steel back to its un-oxidized form.

but this goes both ways, which means any contaminants in your fuel, and thus in the smoke, can react with the metal. the result in that your smelted metal will be full of sulfates,phosphates, and other unwanted compounds that will adversely affect the final properties of the cast. remember: if it's reactive in its metal phase(ie can be rusted or patinated or anodized) then in it's liquid phase it's going to be even worse thanks to all the energy you've dumped into it. a great example of this principle is titanium, which is so reactive with oxygen that you can't melt it outside an inert atmosphere because it'll just burn up. this response ended up way longer than i intended for such a simple question, but working metal is such a complicated topic when you get down to the chemical level, and it's a subject of particular interest to me.

david.lister.1671 (author)weish2015-04-09

So in that case, would it be better to use electric heat to melt the metal?

There was a half decent(very iffy wiring) instructable using an old hob electric ring recently.

IN industry, electric furnaces are used when the purity of the melt is of paramount importance, such as for transformer steel (versus construction steel). Argon gas fill is also needed. But you will need a lot of electric heat! It is usually applied by having an arc discharge to the metal.

bpark1000 (author)Jobar0072015-04-02

If you use "real" charcoal (Cowboy or other brands) that consist of "cooked" wood only, and no clay or coal, which the briquettes contain, you will be relativaly sulfur free. The sulfur (and iron) come from the coal.

bpark1000 (author)2015-04-02

A few comments about the chemistry. When thin aluminum is heated, a lot is lost to oxidation before it melts and coalesces. Commercial recyclers fill the crucible with some sort of molten salt. When the aluminum is dropped in, the salt bath instantly protects the aluminum from the air while the aluminum melts and sinks to the bottom. You could use borax, as that is commonly used to flux metals. It can be poured off into a spare ingot mold and reused. If you don't use a salt bath, be sure to crush the cans completely so they quickly melt. Once you have a "head" of molten aluminum, the next can will melt quickly. You can still put flux on top to clean the metal before pouring.

I recommend you keep water away from the operation, and not use it to cool the ingots. Bad things may happen in the next melting! How do you get the cans totally dry before starting?

GoatDriverR (author)bpark10002015-04-19

BPark1K, super good post. Thats what I'm after with these small squares, keeping them clean.

yehyarocks (author)bpark10002015-04-03

When I get some cans i usually put them out in direct sunlight for a couple hours so the remaining liquid is evaporated. Sometimes if I didnt have time to wait i would cut the bottom of the can and wipe with a paper towel. Thanks for your input on the chemistry! You learn something new everyday.

grooverjamesr (author)bpark10002015-04-02

Very, very good comment!! I love science and that makes the process that much better, thanks for sharing!!

krayzeesmoke (author)2015-04-02

Maybe it's molten glass I'm thinking of...

jeanniel1 (author)krayzeesmoke2015-04-13

No, a drop or two of water won't make molten glass explode, and nor will the water cause an explosion (yeah, bummer). I blow glass, and we even use water to control and shape our hot glass.

jeanniel1 (author)2015-04-13

No, a drop of sweat won't affect molten glass, and nor will the glass explode by a drop or two of water, ice, dry ice. I blow glass, and we actually use water to control the shape of molten glass.

pmandryk (author)2015-04-04

Here's the foundry from Grant Thompson "King of Random",

Here's one showing the dangers of water introduced in to a pour,

lazychris2000 (author)pmandryk2015-04-12

This is also why you should wear leather instead of cotton!

screwitdoit (author)2015-04-03

Questions for anyone. Completely inexperienced in any of this but interested in the process very much. This is a really neat idea but the comments about the moist ground had me wondering what might be put down over it to make it safer? What if a concrete slab were laid below it (or would that be an explosive problem - it is porous and absorbs moisture) or - ? Also, might there be a way to utilize the heat from the foundry itself to pre-dry (prep) the cans before they take the plunge ? maybe start the whole thing without the air on and put several crushed cans in for a minute or two swapping them in and out until all cans for final use have had a non melting prep? Just thoughts, not trying to be overly complex. Thanks and thanks for this instructable.

On a concrete slab is very dangerous, the moisture inside the slab could cause an explosion from the heat possibly, even if it wasn't probable. Setting up cinder blocks meant for outdoor bbqs as a base, on that slab may help, they're fireproof and will prevent heat exchange. Sand on a moist ground may help too if using grass covered yard, it will not only protect the grass and dissipate heat, but with a shop vac you can clean it up in a jiffy.

Predrying cans is not necessary, the cola or water is vaporized at the high temp and will be totally burned off. In most cases it isn't a problem

As one other person stated you can add some Borax to the foundry cup to help in the process. read down and find that. Science and all. Ya know I am at a loss.

Thanks, I had been wondering about sand as well. I had read re: the moisture in cans - saw what was said about a drop of sweat or any other moisture hitting the molten metal but maybe I didn't read far enough. I'll keep my eye on these types of instructables (foundry, casting, charcoal making etc) - this site is pretty awesome.

grooverjamesr (author)2015-04-02

That stainless cup doesn't melt when you get it to 660 C after a while does it?

yehyarocks (author)grooverjamesr2015-04-03

I've done 2 hour runs with the cup. But there are always those freak accidents when a crucible does fail. When melting aluminum always wear some type of leather to protect yourself.

grooverjamesr (author)yehyarocks2015-04-03

Great thanks will keep that in mind.

chancefour (author)2015-04-03

The moss and wood chips shown in the pictures whispers there might be quite a bit of moisture in that area. Moisture and molten metal are dangerous. Find an area a little more dry? If the metal spills onto something like a moist rock, concrete, or brick it might just pop and throw molten bullets up into your body and face. Imagine being splashed with that liquid aluminum. I can't even stand burning my finger on that little bit of ignited sulfur from lighting a match improperly. Really appreciate your efforts. May you have a long, productive, safe foundry experience.

yehyarocks (author)chancefour2015-04-03

Thank you!

david.lister.1671 (author)2015-04-02


I started a new job this week tig welding aluminium channel. Maybe i should bypass the cans and just bring some scrap pieces home to smelt into other more interesting shapes...

I've melted up to 1/4" material but it takes a while for it to completely melt down.

cwright15 (author)2015-03-31

Do the coals not melt the plastic? Also are the coals resting on the bricks?

grooverjamesr (author)cwright152015-04-02

You can use a steel pipe, with an adapter, an elbow and PVC if you like, the steel will not melt and will allow you to pipe in all the air you want at whatever range you desire, the main point I believe this person was making is costs, you can go cheap and do it well

the cool air blowing through it probably helps.

jjarrett1999 (author)2015-04-02

I have been recycling aluminum for years wondering if I could sand-cast with it like I did in school in 1979..I have most of those parts already! This is a very cool instructable. Can you remind me how to sandcast something, too?

achiconelli (author)jjarrett19992015-04-02

There you go.

OMG that is so COOL!! I loved the video he did for the foundry and as soon as I can figure out how to make a gallon of aluminum I will make an ant hill sculpture.

jjarrett1999 (author)achiconelli2015-04-02


yehyarocks (author)jjarrett19992015-04-02

Im working on am Instructable for Sand Casting as well! It's coming soon!

jjarrett1999 (author)yehyarocks2015-04-02

Look forward to it!

Quester-59 (author)2015-04-02

Looks Good, Yet 100% Pure is a Stretch, You'll not face 100% until you fire the plug at lease 5 - 9 times, That Dross is the Impurities found in All metals!

Just for your Information, not met to be an insult. You have their a good Start.

yehyarocks (author)Quester-592015-04-02

After posting this Instructable I realized that Aluminum Soda cans are a tin-aluminum alloy. But for the most part this aluminum is great for casting. Thanks for the input!

krayzeesmoke (author)2015-04-02

Make sure that the aluminum cans are ABSOLUTELY dry, because if ANY other liquid gets under the melted aluminum, it can explode, creating a hydrogen pocket.
I'm not sure of all the particulars but, know for a fact that it's true. Maybe someone can give the specifics.

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