Propane forge built from a soup can


It doesn’t look like much, but this easy to build propane forge is just what you need to try your hand at blacksmithing. [Code Cowboy] took on the build after watching this how-to video which shows the fabrication of a small knife after completing the forge build.

The first step is to eat all of the soup (or beans if you prefer). With an empty can in hand the stand — made of two angle brackets — and inlet are attached. Next comes the heat proofing for the walls of the forge. At first glance we thought that cat litter was one of the ingredients, but that’s just an empty container used to haul playground sand. The sand is mixed with equal parts of plaster of paris before adding water to achieve a clay-like consistency. This is packed into the can, with a small opening to receive the metal to be heated.

The torch itself can be used to cure the heat shield. After letting the mixture harden a 30 minute burn will force the rest of the water out of the heat proofing.

[via Reddit]


  1. steve says:

    While this may work for a few times. If you want something that can be used for a long time you need to make the lining out of refractory cement mix.

    been doing this for years

  2. BoKu says:

    Do you have a better “instruction” for making refractory cement? A DIY method instead of commercial, I’m very interested in this.

  3. Whatnot says:

    I think he should make some more remarks about securing that burner, I mean if people fuck that up and it falls (on that wood for starters) you are going to have a bad time.

    • Pedro says:

      you mean like a sticker saying don’t touch it might be hot? that is stupid. everyone who’s smart enough to try to build this will be concerned about securing it. imo a couple more L straps will do the trick.

      • Whatnot says:

        Yeah right, but we do need to be told to wear safety glasses?
        And I’ve been with people that did really stupid thoughtless things when dealing with fire, so I speak from personal observation..

        Also: it’s a youtube.. with youtube viewers… Try to argue that one.

        Also: Ask Boeing and its million dollar engineers about it when you have a chance. See what they say when the blushing subsides.

        • Daniel says:

          Maybe we should make a youtube video about home made dynamite or something similar and equally volatile and dangerous. Then post it with no warnings or anything at all.

          Improving the gene pool and the human race as a whole by exploiting Darwinism and forcing natural selection might be a good thing? We should do away with all and any warning labels completely IMO.

    • zerobotman says:

      if you drop a propane torch it’s going to go out, not keep burning. I’m surprised he can keep the torch lit at that angle.

  4. Hirudinea says:

    Hot soup commin’ through! This is a great idea but as Boku said DIY refractory cement would be great.

  5. Funkdat says:

    Wonder if you could put a door on there to restrict flow and turn down the torch a bit.

    • Whatnot says:

      But you need access, it doesn’t work as a container but is for realtime heating.

      But if you must, I guess you could make a door using the same technique as the furnace. But then you might have temperature runoff maybe? And you might need some kind of temp monitoring.

  6. madwelder says:

    I’ve always used Tiger Torches and refractory bricks for forging jobs. I just stack the bricks on a steel cart to suit whatever I’m doing and shaped a couple “tuyere bricks” to snugly fit my torch tips.

    I’m curious if there will be spalling problems with this recipe; it hasn’t been an issue with the brick I use. Refractory bricks are soft enough to quickly shape with a hand saw and rasp; a fellow could shape a few of them into a nice lining.

    How about this thought about this design stems from the experience of stuffing torches where they weren’t designed to go: I’ve managed to melt two torch tips over the years. My torches have a long steel handle and are fed by a long, low pressure hose; the cylinders are nowhere near the action.

    The forge is on a metal cart with a firebrick top in a welding shop. When I melted a torch tip all that happened each time was that the torch ended up 3 inches shorter than when it started and there was a puddle of cast iron in the bottom of the forge. This happening with a small torch on a forge in a poorly chosen location could get too exciting for my liking.

    Having said that, it might work just fine; just don’t turn your back on it.

  7. Reg says:

    For a DIY refractory, binding the sand with dry clay would be much more durable. Commercial refractories will last longer, but sand and clay can be easier to source for a limited usage build.

    David Gingery wrote some great books on building simple, low cost furnaces.

    The “Build a Metal Working Shop from Scrap” series is fantastic.

  8. bowler says:

    The downside to using plaster of paris in there is that if you heat it over a certain temperature the reaction by which is sets will be driven backwards, leaving you with a much weaker lining. Some sort of clay, like kaolin or bentonite, would be a better choice.

  9. RandyKC says:

    Probably work OK once.
    At those temperatures moisture is a little more hazardous than you would expect. The hydrophilic tendency of the plaster in the mix would make me very spooky. I’ve seen that plaster mixture used for a lost cast mold but wouldn’t want to push it more than
    once and wouldn’t want to be there when chunks go flying when the can falls off it’s mount.
    Be safe!

  10. solpredator says:

    One tip for making a hotter, more even flame inside the can would be to insert the torch nozzle at an angle allowing it to form a cyclonic motion. This tip I got from the instructions on building your own mini forge at
    I built this and found that the angle was effective at getting the temperature up quickly!
    I’ve since made some additions to that original idea and made a slightly larger forge (sans the video/instructions :( ) by adding additional firebricks and using a BBQ propane tank with a longer hose, regulator, and quick disconnects.
    I hope this helps!

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