Instructables
Picture of Blow Dryer and Red Brick Aluminum Forge
A charcoal forge for casting aluminum electrodes and casings can be made from a blow dryer and some clay bricks. Aluminum scrap comes in a variety of forms, mostly involving impurities of one form or another. This scrap can be reduced to (more or less) pure aluminum oxide (what we commonly call aluminum is actually aluminum oxide) by smelting it and removing the impurities which float to the top. The molten metal can then be cast into forms which are convenient for use in low and medium voltage al-air or al-oxide energy generation systems as well as other casting applications.

Unlike many other forges this one can be reasonably used in a residential environment without attracting undue attention from the neighbors. It's not particularly noisy and doesn't project huge fiery jets. It doesn't require permanent construction or a specialized installation. It can be put together, used and torn down in a single afternoon.



I really like many of the propane designs I saw but most people don't have a propane burner or nozzle assembly to spare so I decided that design which leveraged existing BBQ technology would be more widely useful.

The mandatory note: I believe the insurance company add that says 25 burned down their houses attempting to deep fry turkeys. Don't be an idiot.

No blow dryers were injured in the making of this instructable if would be nice if folks who tried this exercised great care and caution and no humans get injured in trying to do this.

 
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I have a old cast iron stove i use to melt Al. I cut a old Co2 tank for a pantball gun in half and use that as a crucible, its high carbon steel with 1/16" walls and when I pre heat it to a deep red (and dont overheat the Al) I dont get any sticking and minimal slag. i just welded 3 legs@2" on the bottom and a "U" shaped handle for pouring on the top. gave it a football shape in a vice and good to go. it can hold about 3 cups no problem and can hit a good yellow hot without damage. By far the easiest to make and most durable crucible i have ever used.

Some paintball CO2 tanks are actually made of aluminum. This could be a problem. I've seen other crucibles made out of empty propane tanks used for camping.

egbertfitzwilly (author)  afartinthewind3 years ago
I have featured your comment. You should consider doing an instructable as I believe there is a widespread need for crucibles amongst amateur metallurgists.
Snidely704486 months ago

If you can't think of anything else to do with the molten aluminum, pouring it into a fire ant colony produces interesting results.

http://www.anthillart.com/

KeiferMax1 year ago
I have been looking for an easy way to smelt aluminum and I do believe I will give this ingenious way a try. May I ask a few questions?

Why doesn't the steel can crucible melt? Scratching my head on that one.

The "muffin pan" seems to be steel too... Don't need cast iron? That would be great!

Finally, I think I am going to cut the top off an empty mini propane can used for camping as a crucible. (Of course ensuring it is absolutely empty) do you think the sidewalls of this new crucible will be to thick to use in this application?

Thank you for any response and showing me how simple can be best sometimes.
KeiferMax
The steel can has a much higher melting point at about 2500 degrees F
while aluminum melts at about 1,221 degrees F
so you need a much hotter fire to melt the steel
The steel can has a much higher melting point at about 2500 degrees F
while aluminum melts at about 1,221 degrees F
so you need a much hotter fire to melt the steel
RingoWild1 year ago
This is completely brilliant. And your Arthur Miller comment wasn't lost on me. No sir. OK, i have a couple of questions.
1) How long does the molten aluminum stay pourable? I'm sure it hardens pretty quickly, but how quickly?
2) Will silicone molds work, do you think? I'm not sure how high the temp goes in your smelting process. My most interesting molds are those made of silicone, so it would be great if they could be used. However, I have a feeling the temp will be too high.
3) OK, it's more than a couple of questions. Does the aluminum retain its flexibility? Could you pour it into a wire-shaped mold and make aluminum wire?

Thanks for your time!
-- Lori

\i live in new zealand and i cant watch the video
why?

egbertfitzwilly (author)  retrotimelord1 year ago
It is possible that the content is blocked due to copyright issues over the soundtrack. I have a notice from youtube that says this content has been blocked but it doesn't say where.
cfreitas2 years ago
Very nice instructable, I will give a try on this one. I have only one doubt : I understand that the molds are sand made to permit the gas from the molten metal escape from it when solidifying, but, is possible to make molds from cement or something that I can use several times ?

Thankyou for sharing this instructable.
egbertfitzwilly (author)  cfreitas2 years ago
I don't actually do forging so I can't provide any additional insight appropriate mold materials.
xraver70863 years ago
I tried this and i couldnt get the aluminum to melt. any suggestions?
egbertfitzwilly (author)  xraver70863 years ago
I'd have to know more about your setup. I suspect either not enough charcoal or not enough air. Also what were you trying to melt, I cut up aluminum cans and didn't have much difficulty. A solid chunk might be more problematic.

What did you use for a crucible? Some have had difficulties with heavy metal crucibles, they absorb a lot of heat and can take a long time to get to melting temperature.

You could try banking earth around the sides, this will increase the internal temperature.
i used a tin can, like yyou said. i used a whole bag of charcoal, i was trying to melt soda cans. i used a leaf blower for air and it got extremely hot

egbertfitzwilly (author)  xraver70863 years ago
I wonder if the leaf blower might be blowing too much air for this configuration? If there is too much air it might serve as a vent rather than a conduit. You might try a smaller fan if you have one. I was actually actually thinking of going the other way and seeing what results I could get with a small cooling fan.
I use a leaf blower, but the nozzle must be kept a few feet from the mouth of the furnace or the air/charcoal mix will be too lean and the fire may actually be colder (not to mention you could go through 50 lbs. of charcoal in 15 minutes). If you have a very large melter than you could hook the blower right up. However, if you do go with a leafblower DO NOT use wood charcoal. A leafblower used in a tall, thin furnace could give hardwood charcoal enough air to reach steel melting temperatures (as in a cupola), and ordinary bricks can't handle anywhere near those temperatures.
hey its been a while but ive been thinking of a new plan that uses these materials and a few modifications to increase insulation.
egbertfitzwilly (author)  xraver70862 years ago
Cool, I look forward to your instructable. I've been toying with a modified design that uses a gas burner, solves the refueling and fire control issue.
unfortunately, my dad used my bricks for a different project with out asking, and they cant be retrieved(under at least 1 and a half foot of cement). With it being christmas, i cant afford the bricks. when i get them, i will test it out immediately.
NOTE: my bday is commin up, and so i expect to get cash to get bricks, so the inst. is coming soon.
I finaly did it!!! Instead of bricks, i just dug a hole and attatched a pipe to the bottom. worked great!!
egbertfitzwilly (author)  xraver70863 years ago
Do you try again with a smaller fan?
Our county currently has a fire ban and im currently in High School so trying to find the time to do this and a secluded place is really hard, but i plan to use a smaller fan. just need a good, cheap fan.
thecrow1172 years ago
does this furnice get the aluminum hot enough to make lost foam castings?
egbertfitzwilly (author)  thecrow1172 years ago
Since I'm not sure what the specific requirements of lost foam casting is I can't speak authoritatively to that. The aluminum melts, is pourable and so on ( depending on the crucible to some degree ). The charcoal is consumed so if the process is extended one may need to replenish the coals.
jadronx2 years ago
awesome instructable i will be trying this soon!
pdidit2 years ago
lot of great info here. Gotta try this build some other places you all might like are www.backyardmetalcasting.com and www.metalcastingzone.com

2 things that will help the casting are cover flux and degasser A quick search will turn up sources
wilkinde2 years ago
In your introduction you claim that all aluminum scrap is really aluminum oxide. This is false. All aluminum scrap contains aluminum oxide - which is a clear ceramic with a melting point of 2000 degrees Celsius (3600 degrees Fahrenheit). The base aluminum melts at 660 degrees Celsius. This is why aluminum must be welded with an inert cover gas. Once the thin ceramic surface is fractured in air it oxidizes generating more aluminum oxide, until the over all heat builds up enough to fracture the oxide coating away from the edge - creating destructive puddling of the metal near the weld point.

In terms of your casting endeavor, the only significant issue is that the aluminum oxide coating guarantees there will be slag - no matter how pure your aluminum is.
I love this instructable. But the part where you said aluminum is aluminum oxide is only partly true. Pure aluminum metal gets an extremely thin layer of aluminum oxide. Also called alumina it is in itself a great refractory & is extremely hard.
Cool. Have to try this with my heat gun.
egbertfitzwilly (author)  Computothought4 years ago
You mean as the blower or the heat source? I don't think a heat gun will generate sufficient temperature to be useful but would probably make a dandy blower.
a blowr can give much efficient.
Your probably right though the extra heat could not hurt. I can always go to Goodwill and get a cheap hair gun and not wear out the heat gun..
Cold air is denser and thus has more usable oxygen. Hot air is just a waist of electricity.
tomtortoise3 years ago
Yo im wondering if the can is going to melt holding the aluminum
The can is (usually) made from steel, which has a much higher melting point than aluminum. Different steel alloys have different melting points, so I couldn't say what a "tin" can's mp would be without knowing the alloy, but it's generally around 1370 °C. Elemental aluminum melts at 660.37 °C, while Al2O3 has a melting point around 2,000 °C.
egbertfitzwilly (author)  asteidl3 years ago
Thanks for the amazing useful factoids.
egbertfitzwilly (author)  tomtortoise3 years ago
It hasn't yet.
asteidl3 years ago
Love the idea, will try this soon! I drink a boatload of [citrus soda] and [cola] (I'll be fair, and not advertise, lol), and always save my cans for profitable scrap. I'll see how the scrap yard responds to processed ingots! I'm thinking I might even get a better price, since many impurities are removed, and pretty much did what the large recyclers do. The smaller recycling yards compact the cans, then ship them to a processor that either ships the cans to manufacturer (who processes the cans themselves) or shred and melt them down to ingots. I'll report my findings! :D
egbertfitzwilly (author)  asteidl3 years ago
Please do, I agree that you should be able to get higher prices for ingots although you may have to hunt for it. If you have ready access to a source of biochar/charcoal you might be able to move up the food chain ( buy cans and sell ingots )....
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