Backyard Aluminum Foundry


Jim sent in his backyard foundry project. This is an improved version of his previous attempt. It uses a large holiday popcorn tin for the main case. This is insulated using perlite mixed with high temperature furnace cement. It can reach upwards of 1200F, but you’ll still be able to touch the outside of the can, briefly.

21 thoughts on “Backyard Aluminum Foundry

  1. Wow. That is really amazing. I wonder where he got his aluminum from. I know that you can put aluminum with impurities into the crucible and then “skim” the paint and other junk was in/on the aliminum off of the top (if the foundry is hot enough).

  2. There are some books by Dave Gingery that explore home aluminum casting that is both practical and actually produces useful results. Searching for his name will show several people who have followed his instructions and posted websites with the results.

    This particular hack is just a simple “wow, I can melt aluminum with a lot of heat.”

  3. Harddrive cases and platters are an excellent and often free source of excellent aluminum for casting, as well as screen-door frames, *cough*streetsigns*cough, etc… I’m getting very close to building a propane-fired version of the foundry. Cannot reccomend the Dave Gingery books enough, as well as the other books the publisher sells. –>

  4. this little guy can cook pretty well, now he just needs some molds to pour that aluminum into, you know, an object of some sort to manufacture… I’ve heard that automobile piston arms provide clean aluminum, and I have been abe to obtain masses of machine grade material from the engineering shop at the university (they recycle their waste, but only send it out when the huge bin is full) beverage cans are generally crappy stock, full of whatever, causing slag (dross) buildup. This back yard stuff can also be done with lead, and with a slightly different process, iron (the coal is charged in the crucible with the metal and flows out of the bottom). I talked to a guy once who had made a small brick furnace on his property which operated on a small blower fan like the one featured and natural gas capable of burning out wax from plaster molds (~1200 for a couple of days) and heating bronze (~2400 F). The popcorn furnace might also benefit from having the blower pipe entering the chamber at an angle, swirling the flame around the crucible to help heat evenly. good pick eliot!

  5. its been said but, WOW. my boyfriend & bestfriend work at a recycle yard and have access to all kinds of metals that they like to play with including aluminum. cant wait to show them this. by the way have you ever seen magnesium burn ???

  6. its been said but, WOW. my boyfriend & bestfriend work at a recycle yard and they like to play with all kinds of metal including aluminum. cant wait to show them this. by the way, have you ever seen magnesium burn ???

  7. This is darus, the originator of the foundry website. For my first attempts I just melted down a bunch of beverage cans. It takes a LOT of cans to get a little bit of aluminum. You also get lots of crud and nasty fumes. Best to stay upwind.

    Better results can be had by melting down scap aluminum that was cast in the first place. As a few other folks mentioned, pistons, valve covers, tranny casings and so forth would be good sources.

    As for how to create something useful, the process is called “green sand casting.” (Google for it) A mixture of clean, fine sand and a binder of clay and water or oil is rammed around a pattern. When the pattern is removed, a cavity is left in the sand that can be filled with molten aluminum. When the aluminum cools, the sand is broken up and the casting is removed and cleaned up.

    Thats a basic description of the process, anyway. Its a little more involved in real life. Getting the sand mixture just right is kinda fiddly.

    The gingery books that have been mentioned have good information about doing it in your backyard.

  8. My Dad used to run a one-man aluminium foundry before he retired. Sometimes as a kid I used to go to work with him to help out. Lots of cool stuff to play with, like Sodium in metal form (added to the aluminium to change the properties I think).

    As Darus mentioned casting is often done in green sand, but also they use regular yellow sand which is treated with something (sodium silicate?). When you spray CO2 on this it hardens into sandstone. I used to make ‘cores’ which are little shapes of solid sand that are inserted where a ‘gap’ needs to be.

    It’s a very skilled art, I could never stand near the furnace for more than a few seconds.

  9. i have a foundry, i saw one on a movie not too long ago exactly like mine and they were melting gold. It even has a big dipper or spoon. It is a bit rusty. What can I do with this thing and how do I get started?

  10. first you’re probably goona want to remove the rust off your gear, maybe your auto shop will have a glass blaster (if you are in high school) or look for someone with a glass or sand blaster, it’ll only take a few minutes to blast off the rust and leave a nice finish.

    if you want to know what the foundry can do, you’ll need to post some specs, since not all foundries are created equal

  11. A friend of mine back in college once made a one shot deal to melt down some aluminum.

    He took a bunch of fire bricks (bricks made to build a barbeque pit or what have you) that we had laying around, and built a little box with a hole in one side towards the top. He also left a small hole on the other side for airflow. He shoved a bunch of coal in there (which he “procured” from the power plant on campus) and got it lit with the help of some alcohol. Then he attached a shopvac to a copper tube with some duct tape and used it to blow air into the chamber. This was after a few attempts, of course, the first few attempts melted the plastic shopvac hose. ;)

    In any case, once he had it nice and hot and had added a bunch more coal to it, he put aluminum tabs from the tops of soda cans into a ceramic crucible thing, and used fireplace tongs to put it on top of the coal. The aluminum melted, and he poured it into a sand cast thing he had made using sand from our volleyball pit. Don’t recall what he was trying to make, exactly. A part for something or other.

    Anyway, it worked fine. The ceramic crucible got so hot that it ended up melting/breaking when he grabbed it with the fireplace tongs though. He was able to pour, but it destroyed the crucible in the process. Not made for those temperatures, I guess. The fire bricks were none the worse for wear, they didn’t even get hot on the outside of the makeshift furnace, and after brushing the crap off later, they were fine.

  12. for an excellent source of lead go to a tire shop, they tire balancing wheights are often just lying on the ground outside, i suppose you could go inside and ask for them but i just go when they are closed and take a large wal-mart bag full of them home

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