From Cans To Sheet Metal, With Ease

Aluminium drinks cans make a great source of thin sheet metal which can be used for all manner of interesting projects, but it’s safe to say that retrieving a sheet of metal from a can is a hazardous process. Cut fingers and jagged edges are never far away, so [Kevin Cheung]’s work in making an easy can cutter is definitely worth a look.

Taking inspiration from a rotary can opener, he uses a pair of circular blades in an adjustable injection moulded plastic frame. If you’ve used a pipe cutter than maybe you are familiar with the technique, as the blade rotates round the can a few times it slowly scores and cuts through the metal. Doing the job at both ends of the can reveals a tube, which cna be then cut with scissors and flattened to make a rectangular metal sheet. Those edges are probably sharp, but nothing like the jagged finger-cutters you’d get doing the same by hand. The full video can be seen below the break, and the files to 3D print the plastic parts of the cutter can be found at the bottom of a page describing the use of cans to make a shingle roof.

56 thoughts on “From Cans To Sheet Metal, With Ease

  1. Great work. I was planning pretty much exactly the same thing but never got around to it. :)

    Next step…make 3d printed forms to press housings and shielding from them.

    Also, don’t forget they are often (always?) plastic coated on the inside.

  2. This doesn’t (didn’t) work in all countries, though.
    Here in Germany, we used to have very sturdy aluminium cans (you know, those forbCoca Cola, Fanta, Sprite etc).
    You couldn’t squash them with your hands, by any means.
    Some cans were so sturdy that you could stand on them.
    Taking them apart with scissors was dangerous, it wasn’t sich soft material as shown here.

    1. Drinks cans in Germany are aluminum (I live in Germany.) You can certainly crush them with your hands.

      Older cans were made of “Weißblech” – thin steel sheet metal, plated in tin. Those were difficult to crush by hand. You had to use “tin snips” (special metall cutting scissors) to cut them open.

      Steel drink cans were normal in many countries until the 1970s.

      https://en.wikipedia.org/wiki/Drink_can

      1. Thank you. I think it must have been the older type, then.
        Anyway, I had held such rpbust cans in my hands in 90s and early 2000s, still.
        Back then, the thickness of the metal must have been greater than now.
        I suppose it’s like with the PET bottles who are getting tinner and tinner each year. :(

      2. In some parts of Asia (including Japan) steel cans were still in use well into the 2000’s. Certain brands just kept using the equipment they already had until it was cost prohibitive. Dr. Pepper was one holdout.

    2. I’ve cut open an (empty!) Revell compressed air can (those are used with airbrushes instead of compressors), I thought the aluminium would be very thick because the can was quite hard. But it turned out pretty flexible when cut, and it was somewhat thicker than ordinary beer cans but I believe still much under 1mm.

  3. The Netherlands recently introduced a return fee on aluminum cans. A win for the environment, probably, but it does remove a cheap source of aluminum for hobbyists. At 15 cents a can really isn’t worth it to scrap them instead of returning them.

    1. provided that You can actually buy
      a) this kind of sheetmetal at all
      b) price per m2 is less than 0.15€
      c) shop is willing to sell less than 4m2

      so comparing by price only – yes, not worth. But then comes in availability..

      1. Internet solves lot of availability problems. But with 0.15/0.20 eur deposit, reusing cans seems surprisingly economical. Standard 330ml can should give about 90mmx205mm sheet, or 0.01845m², or roughly 10 eur/m². The closest thing I could quickly find is aluminium flashing, I think you can get 6″x50′ roll for about 30eur, or about 13 eur/m².

        Sure, the flashing is almost double the thickness of typical can (0.2mm vs 0.1mm), but if you just need some Al sheet and the thickness doesn’t matter much then cans don’t seem all that bad.

        1. I’d say that cans will pretty much always win in cost as well, since almost all usecases you will have most of the can left over. Making a roof is an exception of course, but is also very expensive in labor so just buying more suitable material will probably be more economical even if your time and cans are free. If you use corrugated steel for example, you don’t need as much support under the roof since it also provides some structure and can be walked on and can carry lots of snow.

    2. Germany (where I live) has had a deposit in aluminum cans for quite some time. The deposit is 25 cents.

      As a source of raw materials, they are far too expensive – you’d do better to turn the cans in then buy sheet aluminum from the returned deposit.

      Given a deposit of 25 cents per can, and a weight of 18 grams per can, the cans are worth about 13.9 Euros per kilogram if you turn them in for recycling. That’s 56 cans.

      I find aluminum roofing for 6.10 Euros for a sheet that weighs 2.25 kilograms.

      As roofing material, cans lose by a long shot.

      On the other hand, on a Saturday or Sunday afternoon when there’s no place close by to buy sheet aluminum and I need a small piece to finish a project – well, the can is gonna get whacked.

      1. I remember buying a can of soda for 25 cents from a vending machine, can’t be more than a decade ago. But that’s in the U.S. where the deposit is something like 5 cents and the only recycling center doesn’t pay.

        1. No, that is only told to customers by shops who want to keep the return fee. The law says, when returning damaged cans the full fee has to be returned, and a court has decided, that it is sufficient, when one can discern the fee logo. Not even a readable bar code is required.
          My return routine is “I want to return these.” – “You must put them into the Pfandautomat, otherwise we can’t take them.” – “The law and the judges say something different” – “We can’t book them, when they are not in the Pfandautomat. Go to some drinking market, they have more possibilities” – “Ok, then I want to speak to the chief” – “Here is your money.” – “Thanks.”
          Every time. I hate that routine, but I’m not willing to reward such a behaviour.

          https://www.verbraucherzentrale.de/wissen/umwelt-haushalt/abfall/fragen-und-antworten-zum-einwegpfand-dosenpfand-11505#10

          1. Are you saying that you think using the courts to force the shop to pay the full fee for a cut-out logo is fine, but trying to get people to return the entire container if they want to receive the recycling incentive is despicable behavior?

          2. No, I say rejecting damaged, but complete containers on a regular basis is despicable — as despicable as misusing the “Einwegpfand” as loop hole to cheap out on the demand for reusable packaging. The returning of the fee is not tied to the logo, but to the container with the logo, so cut-out logos are rightfully rejected.

    3. We were in Amsterdam this fall, and my wife asked why there was so much trash strewn around. She was told this law has made people dig through garbage cans for returnable cans, and they aren’t very neat about it.

      Those damn unintended consequences.

      1. In Sweden there’s special tubes available on the sides of some garbage cans on the street where you put the empty can. Then people can collect them without going through the garbage can for cans.

  4. Cover one side of these aluminium sheets with high strength double sided tape (leave the backing on ’till needed) and you create an adhesive metal sheet that can be wrapped around cylindrical things for repairs or reinforcement. Allows you to instantly fix light duty tubing in some circumstances. I keep a few sheets of this stuff in my materials collection as it’s proven handy over the years.

  5. Well this seemed like something much easier 3D printed than injection molded. But, hey, he [supposedly] makes the STL files available. But first you need to create an account and verify your email and the email validation is not working. But I got to the downloads once the acct was created (without verifying it) and there is a mandatory-voluntary donation required. I’m not paying 5€ for his STL files.

    1. Yes, it’s called a “topless can cutter”, “bear,soda can cutter” and other names. Some designs have one, two or three circular blades. I have one that is sort of round with three blades. It cuts both tops and bottoms from a can.

      I thought the same thing, that you could stack cans to make a pipe. Perhaps make a solar hot air heater. Never did it, as I have no use for one.

    2. I use the same can opener for the bottom part also. The trick is to not turn the handle, rather pinch through one by one, it makes a rather ragged edge.
      After that i cut it straight with a tin snips.
      I processed about 400 cans, my usual time is like 10 sec top, 15 sec bottom, about 10 second heightwise. Then both edge with a tin snips like 20 second each. You need to pay attention with the tin snips when using so it makes a continous line not some sharp overhung lips with each cut.
      So a can processing is under 2 minutes.

      I’m not certain with the economics (wanted to use it for a firewood shed, the problem is; these small sheets can easily tear apart much like a scotch tape. Once the tear started its like no effort to pull the sheet into two pieces)

  6. I’ve used these for a few things… shim material, as “paper” for small art pieces, for pinholes in pinhole cameras. Also tried (with varying degrees of success) scratching the inside with my vinyl cutter and etching (copper sulfate + salt + water) to cut pieces out. Probably easier to sand off the paint on the outside than to remove the plastic inner lining if you need bare metal.

  7. I’ve used pop can material for quick and dirty solder stencils. The thickness worked out well to deliver a suitable amount of solder paste to each pad. I sandwiched the thin sheet between a quite thick lower piece of aluminum and a relatively thin (maybe 3mm?) upper piece, then drilled holes of suitable sizes for each opening. If done carefully, there are no burrs and it just works. Round instead of rectangular openings is a non-issue.

    Pop can shims are also good for adapting bicycle seat posts to slightly larger seat tubes. Just roll to top edge a few times so the shim doesn’t slip down inside the frame.

  8. Several years ago, I made use of soda cans for a few purposes. I made the usual messy cuts with knives and scissors, but I cleaned up the edges with one of the old guillotine paper cutters, which was also useful for cutting them cleanly into strips.

  9. I like to melt my aluminum cans in a steel bean can (as a makeshift crucible) in the woodstove, where the temperature is high enough. then i get these hockey-puck-shaped aluminum ingots

      1. For what it’s worth, I have spent time at a aluminum recycling center where they melt big bales of crushed aluminum cans into solid aluminum billots. The process seems relatively clean, at least compared to steelworks that you can smell from a mile away.

  10. All of a sudden my stock of 30 cut and unfolded beer cans hidden deep starts to make sense. Besides being ripped off for the recipient (plastic, metal, glass), their thickness starts to become risable and many deformed PETs are not accepted by the machines.
    For reasons I stopped buying beverages in aluminium cans, but I saw how thin the PET bottles has become. Also all hopes for stringifying the PETs are almost gone (only big bottles of 5 liters and up are not returnable, yet).
    The funny thing is that the recycling machines are shutdown in the evening so their operation would not disturb the people living close to the shop. I know a shop with a restaurant wall in wall, where sometimes, quite often, there a weddings. This is Eastern Europe weddings, with music so loud after 2 am that I doubt that anybody will hear the PETs or cans being crushed or the bottles being shattered, even holding the machine like a beloved one, so perhaps at the 10th try it will accept the final PET so you can take your ticket (not money) and go home, kinda pushed by the sound waves.
    Aaahhh, recycling, what a bliss…ter after you cut your hand in freshly cut aluminium and run to the sink to pour cold water to stop the bleeding, but there are water company is doing repairs and only hot water flows on both water pipes (remember the location) and besides a nasty cut you also got a nice hot water burn, slowly turning into a blister. At least is morning and the music is gone.
    Now cars horns are shouting angrily at each other.
    Another day in (recycling) Paradise. Oh, think twice …

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