Building a foundry in your backyard

[th3BadWolf] has been wanting to build a foundry for some time now. Done right, it’s a very neat tool; it’s fairly easy to do aluminum castings, and if you’re clever enough a foundry can lead to building large machine tools such as a lathe or a mill. Anything worth doing is worth overdoing, so [BadWolf] is designing his foundry to melt 150 pounds of aluminum every 45 minutes.

The build began with a humble oil barrel. [th3BadWolf] cut the top off of the barrel and began lining the inside of the barrel with a ceramic blanket and refractory bricks. To hold this somewhat precarious assemblage of blanket and brick together, [BadWolf] is holding everything together with 3000° F cement.

The body of the furnace is nearly complete, but [BadWolf] still has to drill a few holes for the burner system. He’s going to start each burn with Propane, then move over to engine oil when the furnace gets hot enough. Truly an awesome project, and we can’t wait to see the results.

Comments

  1. dougie says:

    “Truly an awesome project, and we can’t wait to see the results.” Addendum: So long as said results don’t include an incinerated dwelling.

  2. Chris says:

    Holy crap! What is he making that he needs 45 lbs of aluminum every 45 minutes??? Most of the work in casting/foundry is in pattern and mold making, not the aluminum melting. I understand the desire to see how big you can make something like this, but then you’ll discover that you have 45lbs (~8 litres) of molten aluminum. All at once. In your back yard. Where it might be spilled. If he’s melting a lot less at a time (like the more typical litre or two), he’ll be using an awful lot of fuel to do it with such a big furnace.

  3. fartface says:

    Watch it doing this. The smells from a forge are strong and if you build one in suburbia, you will get cops at the door.

    The Soccer mom down the street will not like the “icky” smells and complain you are killing their purebread pomeranians.

  4. S says:
    • JB says:

      I hate the noise of bricks rubbing together when placed in. Cool project and I would probably go for something like this in my backyard if I knew how to handle molten metal (@fartface: kicks neighbor’s pomeranian back into their property :P )

  5. medix says:

    Killer project. Can’t wait to see it up and running. I’d love to know what he’s casting.

    To the rest of you: Worry less. BUILD MORE.

    • Chris says:

      I’ve seen the scars from home foundry accidents… In this hobby, the answer should almost always be worry more. I’ll never stop casting as a hobby, but the fact is, it is extremely dangerous. Never forget that, and you should be fine.

  6. Oliver Heaviside says:

    A friend of mine had built a small foundry setup to melt aluminum and cast something from a small ladle sized but of aluminum. Not a dumb guy by any means, and he always wore a face shield.

    One day (after having done it with great success a few times) he went to make a pour into a smallish sand casting mold that had a bit of moisture in it.

    It blew up, and shot up underneath his face shield, sputtering his face with aluminum and sand. he’s lucky his eyes closed instinctively.

    For the rest of his life, his face will resemble a combination of sunburn and dish pan hands. He regrets it greatly, and cautions anyone doing amateur foundry work to ALWAYS assume that the mold is going to explode and spray you with molten metal.

    Even if it’s hot out, wrap yourself up. And also – don’t melt lead on a kitchen stove, and especially in great volume. A kitchen vent fan is not enough, especially while your kids watch.

    • Some Random Dude says:

      “A kitchen vent fan is not enough, especially while your kids watch.”

      Sure it is. You’re greatly overstating the risks of lead fumes, which occur at 900F. Lead melts around 650F depending on the alloy.

      • Oliver Heaviside says:

        yeah.

        I’m not normally a safety nazi, but there are developmental issues with the CNS of kids for Lead and lead by-products. The issue of my concern was with the particulates and byproducts settling into the surrounding area and into food and food prep areas. I am not expert on heavy metal toxicity, nor on smelter contamination.

        I was the kid in question, and while it seemed great, years later I was amazed at the amount of what appeared to be oxidized lead on areas around the stove, and the smell of the house for days after the melts.

        Was it actually lead that I saw? Don’t know.

        Dude melted enormous volumes of Lead in order to to make dive weights – hundreds and hundreds of pounds of these things, all made on the kitchen stove over many months.

        I look forward to the first backyard bessemer project.

    • fartface says:

      Which is why you wear a HOOD.

    • Paul says:

      Before my father retired he run an aluminium foundry. I used to ‘help’ him out in the holidays making cores (sand+???+Co2) etc. Even though aluminium melts at a low temperature a furnice of moltern aluminium is insanly hot!

      He also had buckets of sodium floating in oil…

  7. werfu says:

    You should check the alloy concentration in lead before smelting it. Needless to say that lead fumes are carcinogenic.

    • nes says:

      Group 2B posssibly carcinogenic

      Lead is in the same category as gasoline and ferns, i.e. no proven link. Not saying that lead fumes aren’t bad for you, just that they probably won’t trigger a cancer.

      Since when was lead commonly alloyed with aluminium anyhow? Magnesium and zinc are more likely and zinc fumes are really bad for you.

  8. th3BadWolf says:

    Thanx for sharing Brian. If I may I’d like to address the safety concerns you guys are pointing out. First,I already exploded a cement mold filled with lead when I was younger and the luck I had of not getting injured is the most powerfull motivation anyone can get to stay safe. About the ‘backyard’ concerns, none of it matters here. The whole foundry is being built and is going to be operated on a comercial site my family owns and on which a special area is going to be set with the necessary ground layers to prevent any spillage fire or problems. Finally I’d like to assure you that most of the things I do are done in a safe way thanks to the mechanical engineering degree i’m undergoing and the speciality courses I took in industrial processes. I hope this clears out the safety issues you had. thanks again for checking it out,suggestions are always welcome.

    • Wolf,

      I’ve looked into doing a simple flower-pot foundry for a few very, very small castings (less than a pound of aluminum). For the life of me, I can’t find fire clay.

      I don’t know if this is a west coast thing (Pennsylvania, here) as it seems fire clay is used in adobe or something, but this stuff is literally impossible to find.

      This is what I’m using for a guide to refractories. Perlite, sand and cement are easy to get, but I’ll be damned if I can’t find fire clay. And, yeah, this is after calling a few concrete companies.

      • Josh says:

        Have you tried looking for “refractory” clay, mortar, sealer, etc.? McMaster-Carr carries it, so you might check there or Grainger, or a local fireplace supplier/installer.

      • th3BadWolf says:

        Brian,

        I know the frustration about the recipes on bymc as I’ve read em all. They look a bit old to me (kinda like the anarchist cookbook where ingredients were readily available).

        The stuff I’m using is a special concrete rated 3000 deg F and it’s called ULTRATEK 60. The company where I bought it manufactures ovens of all sorts and stock about 50 brands of refractory concrete.

        http://www.mtsavage.com/ProductInformation/ProductLines/GunningMixes/tabid/84/Default.aspx

        They should have some re-seller all around since it’s a US-based company.

        The price I got is 40$/bag of 50lbs,and 3 bags make a cubic feet….it’s terribly dense.

        If you guys are really unable to find some maybe we could arrange something but I’m pretty sure you’ll find something on your side.

        Also,the firebricks aren’t needed for small scale furnace,I could have gone with a complete concrete shell but the price would have been ridiculously high,explain their use.

  9. Sam says:

    Im very glad you know what you’re doing.

  10. a.k says:

    Dave Gingery has written a few books on the subject. http://lindsaybks.com/dgjp/djgbk/found/index.html
    Pretty much any book from lindsay is awesome.

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