The Tuna Fish Sandwich Foundry

Can you build a foundry out of a loaf of bread and a can of tuna fish? As it turns out, yes you can. And not only can you melt aluminum in said foundry but you can also make a mold from plain beach sand and cast a usable part.

Through the magic of backwoods engineering and that can-do Canadian attitude, [AvE] demonstrates in his inimitable style how a pyrolized loaf of sourdough bread can serve as a perfectly acceptable foundry, using a tuna can as a crucible. We covered [AvE]’s carbon foam creation process before and showed some of its amazing properties, including the refractory characteristics requisite for foundry service. Once reduced to carbon foam, the bread can easily handle the flame of a propane torch and contain the heat long enough to melt aluminum. And using nothing more than beach sand, [AvE] was able to lost-foam cast a knob-like part. Pretty impressive results for such a low-end, field expedient setup.

Normally we warn our more tender-eared readers about [AvE]’s colorful language, lest they succumb to the vapors when he lets the salt out. But he showed remarkable restraint with this one, even with his cutting mat aflame. Pretty SFW, so enjoy seeing what you can do with nothing.

[via r/skookum]

39 thoughts on “The Tuna Fish Sandwich Foundry

        1. Yes, the best fish in a can, that tastes like a freshly caught Tuna or Salmon comes from a company calked ‘RainCoast ‘ , I touch no other cans, as I don’t even know that it be for other creatures:)

  1. AvEs language never bothered me. Maybe because I’m from a generation before snowflakes, safe zones, and microaggressions existed. Personally i think too many people are pansies these days. Now get the F*** off my GD lawn, you little piece of s***!

      1. As a kid, it was on a trip to Canada that I saw a swear jar for the first time. Its pay scale was “egads and such” (5 cents), “damn and such” (10c), and “%&+#@ and such” (25c). This was probably 25 years ago though.

    1. It’s not that his language offends me or anything… it’s just… unnecessary. I like to learn and watch a lot of things online / on youtube… and it doesn’t require a million swear words and anecdotes. And this also has nothing to do with being a ‘snowflake’.

  2. Great idea, should have used a tray of sand under it though as destroying the cutting mat wasn’t worth it. Oh well nobody died, lost an eye, or got a lap full of molten metal, so it could have turned out worse.

        1. I doubt it. Cat litter is very coarse compared to sand, the finish isn’t going to be too good. Also, cat litter is almost entirely clay. If it’s packed tightly to give a smooth surface it’s almost impermeable to the gases that need to escape. Exploding molds are very poor technique. (A little clay— 4 – 15% — is added to fine sand to make molding sand stick together.)

  3. Now the question becomes, if you’re doing survival style foundry work like this out of found aluminium, you always lose a portion to oxidation. Aluminium oxide is very stable – contrary to iron oxide which can easily be smelted back to iron. How do you do the same with aluminium?

    The reason why aluminium was more expensive than gold back in the day is because it’s really difficult to reduce down to metal.

    1. Yes, the dross is quite stable. find a way to foam it up and make a foundry out of it? ;) As you say, there i no easy way to reduce alumina oxide back to aluminium.
      Personally, I’d experiment a bit more with the bread thing: it looks like he used very fluffy white bread for it. Would a denser bread yeld a better carbonised material? can you add stuff (sodium silicate, clay, alumina) to the dough that improves carbonised properties?

      1. Not sure the voltages but apparently it takes some high amp DC to reduce to elemental metal.
        Too bad we cant get dry cells anymore with the carbon rod(great electrode) down the center.

          1. The released oxygen burns away the carbon electrode as CO2. I recall the invention of this process was first carried out in a frying pan so it seems that no gas shielding is absolutely required though probably helps alot.
            Sadly I think the 6v lantern battery is a N American thing, I have looked for them as they are also often a great source for bulk AA cells.

          2. Sorry, didn’t realize that.
            You could attempt pyrolysis of wood to make your own carbon (inside nested soup cans). My attempts failed, but I think I used the wrong type of wood.

          1. In the 80s I visited the US for a science thing as a kid, I received a box of ‘science stuff’ including a 1.5v cell something like 60mm round x 150cm tall, I recall it was an ignition cell for methyl nitrate diesel model airplane engine startup glow coils. That thing had a huge (20mm?) carbon rod inside but I had to throw it out before I came home.
            I was excited as it was one source of materials mentioned in a 1950s home science lab book for kids along with making a cloud chamber for identifying subatomic particles, a Kerney DIY radiation dosimeter, glassblowing over an alcohol flame, and a carbon arc furnace among about 50 other great home lab hacks.
            Though if you want great carbon rocket nozzles flip the equation and ask an aluminum smelter for some burned up electrodes, the ends are enough for several nozzles .

    2. Commercially, aluminum oxide is dissolved in molten cryolite (at about 1000 F) and a few volts at several hundred thousand amps is passed through the mixture to deposit aluminum metal. Cryolite is used because Al2O3 by itself melts at a far higher temperature.

      Before the Hall-Herout process was discovered, aluminum oxide was reduced to aluminum metal using molten(!!) alkali metals such as sodium and potassium. Not something to try in the home lab.

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