Custom Engine Parts From A Backyard Foundry

Building a car engine can be a labor of love. Making everything perfect in terms of both performance and appearance is part engineering and part artistry. Setting your creation apart from the crowd is important, and what better way to make it your own than by casting your own parts from old beer cans?

[kingkongslie] has been collecting parts for a dune buggy build, apparently using the classic VW Beetle platform as a starting point. The air-cooled engine of a Bug likes to breathe, so [kingkongslie] decided to sand-cast a custom crankcase breather from aluminum.

Casting solid parts is a neat trick but hardly new; we’ve covered the techniques for casting plastic, pewter, and even soap. The complexity of this project comes from the fact that the part needs to be hollow. [kingkongslie] managed this with a core made of play sand and sodium silicate from radiator stop-leak solution hardened with a shot of carbon dioxide. Sure, it looks like a Rice Krispie treat, but a core like that will stand up to the molten aluminum while becoming weak enough to easily remove later. The whole complex mold was assembled, beer cans melted in an impromptu charcoal and hair-dryer foundry, and after one false start, a shiny new custom part emerged from the sand.

We’ve got to hand it to [kingkongslie] – this was a nice piece of work that resulted in a great looking part. But what we love about this is not only all the cool casting techniques that were demonstrated but also the minimalist approach to everything. We can all do stuff like this, and we probably should.

[via r/DIY]

39 thoughts on “Custom Engine Parts From A Backyard Foundry

    1. Or an old metal coffee can filled with charcoal, and a soup can for the crucible (one use), and a shop vac with a router speed control (to slow it down) for bellows. That set up will melt a soup can full of metal in 15 minutes though it won’t last more than a few melts.

      1. One might use a CNC machine to cut all the keys and case in some soft, easy to remove material (like wax or plastic foam), then use that to make form with chamotte clay and remove the material prior to pouring molten aluminum. It would be even more awesome with iron, steel or brass for that extra steampunk vibe…

        Few years ago I wanted to make my own foundry, but because I can’t exert myself too much, unless I’d like to be blind, I’d have to design and build some kind of exoskeleton to increase my strength without increasing strain to my body. I can’t afford that for now, but it would make an epic project for HaD…

        1. I know people who have 3d printed forms with low infill, then cast that in plaster, then poured the aluminum in on top and burned out the PLA to form some really nice shapes.

          1. You can use my new 3D Printed Lost Shell Sand Casting technique that eliminates the need to make cores – direct from 3D prints. It is like my Lost PLA technique (search for “Lost PLA” on Youtube, my video is the first [non-ad] hit), but eliminates all the extra steps of making a plaster mold, burning it out, etc. Basically you just bury the print in sand and cast! The molten metal vaporizes the plastic and whatever doesn’t vaporize floats to the top! Another bonus is it can even be used for steel! I have a 10 minute documentary of the process on Youtube, search for “Lost Shell Sand Casting” and I’m the top [non-ad] hit there as well.

          2. It works most of the time, same with links to .jpg files on image hosting sites.

            With your castings, have you tried this method of using ceramic shell slurry to ensure the surface is perfect, no sign of the casting sand?

        1. You need to look at the flame spectra to be sure of what alloy you had. HD frames are cast, beer cans are worked from a blank so they need to be a very ductile alloy.

        2. You probably don’t actually want beer cans. They’re almost pure aluminum. The best stuff I’ve found for casting is car pistons. They have a lot of silicon in them, meaning they’re harder to machine afterwards, but they cast beautifully. You also lose less to oxidation than with beer cans, and you can do a whole mess o’ casting with just a half dozen pistons, where the equivalent would be entire trash bags full of crushed cans.

          1. The body & lid section are two different alloys optimized for mass production while still serving their intended roles. The body is a soft alloy & the lid is harder.
            @sdfsdfd
            Paint & coating will burn off in the furnace. You may get more dross due to them, but that’s nothing a bit of flux won’t solve. Also adding cans to a pool of already molten aluminum reduces oxidation of the comparatively high surface area cans.

          1. I don’t know – cans have a coating on the inside of them, just as glass bottles do. If I remember, bottles have tin tetra-chloride spray on the inside prior to them being annealed. Can’t speak to the cans though, I’m sure there is someone here that has been around the process.

          2. Napoleon learned a while back that metal in direct contact with food for prolonged amounts of time gives you inedible food. Beverage cans are coated in food safe plastic, specifically epoxy.

        3. go to an auto wreckers and get a few bell housings is the simplest way.
          cylinder heads have (sometimes) steel or brass inserts, you can strain them out.

          I’ve broken up bell housings with a sledge hammer, way less effort than using a saw

  1. Let me start by saying I’m not being critical – I honestly don’t know and am asking for clarification.

    Isn’t the metallurgy for aluminum engine parts a rather critical part of the process of engine design? I mean, an aluminum engine block and a beer can aren’t going to be made of the same alloy… are they?

    1. It’s for an air intake part – not really a lot of stress on it, so I imagine it’s a non-critical whereas strength is concerned. But it does beg the question as you have posed – how pure is the AL in beer cans?

      1. About 95% aluminum, 5% a couple of other things. It’s not very strong. Aluminums with more silicon are both stronger and flow better, and aluminums with a fair amount of magnesium are also strong and good choices if you don’t have fine features.
        But, realistically, you can pick up a ton of strength by doubling wall thickness. Cast metal parts can be plenty tough if you’re a bit careful with your design.

      2. AA 3004, AA 3104 or AA 3204 are the alloys used for the body (depends on manufacturer and customers deep draw requirements), and the tops are usually AA 5082 or AA 5182.

  2. This is a sweet piece of work. It’s rare to see people doing cored casting at home, and even more rare for people to spend the time to get that good a finish on the result. I wish my castings looked this good.

  3. Dear HaD: Care to tell us which one of the randomly highlighted words in the article is the actual link to the actual fucking thing in the title?

    Or is accessibility and usability not hacky enough?

  4. I have built furnace out of two steel buckets and some refractory, and it works great. I have tried to cast an intake for my moped but the core is pain to make correctly. It’s important that the inside surface of the finished casting is smooth and correct diameter. It’s also good to add little bit of flour to the core sand so it collapses more easily.

  5. I read that first sentence “Building a car engine can be a labor of love.” and got very confused. I thought he was trying to build an entire car engine from beer cans. Then I somehow missed the part that said he was just building the one part and read the rest about the process he was using. Building a whole engine that way… that’s just too much!

  6. Anyone interested in casting needs to check out Myfordboy’s website and Youtube channel. He doesn’t yack when he’s working — which is either pleasant or annoying, depending on your tastes* — but his methods and work are unparalleled in the fields of casting and machining. While its great to see so many people interested in backyard metalcasting, there are definite quality issues with many of their methods. You might as well start with one of the best.

    https://www.youtube.com/user/myfordboy

    p.s. Do yourself a favor and don’t use beer cans in castings that matter. Just because you CAN melt it doesn’t mean that you SHOULD use it. Sure, aluminum cans are easy to source, but you can do better. A serious artist can get house paint easily at a big box store…but would they use housepaint for a commissioned portrait on canvas? I don’t think so.

    *I actually started a Youtube channel called “Quiet Craftsmanship” because I find videos with no or little talking to be really refreshing. With the exception of AVE — who is awesome in own way — there’s too much talking in Youtube videos. Sometimes its nice to just watch a master craftsperson do their thing — their work speaks for itself.

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