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Much to my dismay, my apartment building recently canceled their recycling program. My household generates a fair amount of waste aluminum cans that we were previously sending to the local recycling plant. Instead of going out of my way to take large bags of leaky cans to the recycling plant, I was wondering this:

What are the best uses for aluminum cans/foil? I was thinking about building a tool in my detached garage/workshop for melting the aluminum down, but don't know what I would do with it once it is cast.

  • Melting aluminum is not trivial like melting lead or tin. – blacksmith37 Apr 7 at 20:20
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    How about generating less waste first, and then wondering about how to dispose of it? Also write a concerned letter to your landlord, as to why the program was cancelled etc pp. – Erik Apr 9 at 10:13
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    Yall are doing a great job trying to convince me not to melt the cans, but how will the engineer in me be satisfied if I can’t build myself a new tool? ;-) – Shady fortune-teller Apr 10 at 15:23
  • The aluminum cans should not be washed because of the enormous use of water. That's why I suggest collecting the cans in a chest freezer. Then I suppose that the chest freezer has a thermostat so that the freezer does not run all the time. But how many solar panels and what type of setup would be needed to run the freezer ? – S Spring Apr 10 at 19:42
  • @SSpring 1 ounce of water, 2 or 3 times, is hardly enormous. That's all it takes when the can has just been emptied of contents and everything is still wet. Once sugar-puddles dry out, a 12oz can needs 12oz of water in it to soak, then a couple more 1oz splashes. Still not enormous. – Harper - Reinstate Monica Sep 6 at 6:28
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1. Reuse

There are several websites describing ways to reuse aluminium cans, for example this page on WikiHow.com or this one on Earth911.com. Most common is to reuse them as a holder of some sorts (e.g. a pencil holder or candle holder), as earrings or as coasters. But I guess there a only so many pencil or candle holders and coasters you can use, so I think eventually it's inevitable that you are left with cans for which you have no purpose.

As several other answerers have suggested it's probably not a good idea to try and melt the cans yourself. This will take quite a bit of effort to setup and requires lots of energy every time you heat a new batch. Melting yourself is less efficient than industrial melting, so your environmental impact will most likely increase if you do.

2. Reduce

Perhaps you can try and reduce the amount of aluminium cans you buy and instead switch to a material that is collected for recycling in your local community (maybe glass)?

3. Bring to local recycler

If reusing and reducing is not an option, the only thing left is to bring the cans to a near-by recycling drop-off point. Crushing them first will reduce the size and makes it easier to carry. If there are no near-by drop-off points, try and persuade your city council to setup a collection scheme. Surely more people in your area have the same problem and you can join efforts in convincing the authorities to arrange for something.

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    Also, I've heard it's important to remove paper and glue, and that cans with paint (like beverage cans) should be done separately, so that the paint doesn't contaminate the purer aluminum from other cans. – LShaver Apr 13 at 18:23
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You should do like all the commercial reverse vending machines do: crush the aluminum, don't melt it. The other answer already has one example way of crushing aluminum. If that doesn't work, well, try to find some other way instead of considering melting.

Another way of crushing is to put the can on its side: it's less strong when placed that way, and the force required to crush it should be somewhat lower.

Each and every time you melt aluminum you use some sizable amount of energy as heat. Thus, the amount of times you melt aluminum should be limited preferably to be done only once at the recycling facility. Not only that, but it's no trivial to melt aluminum because of the high temperature required. You also need a container of significantly higher melting point than aluminum (such as steel) and a way of ensuring heat conduction doesn't set your workshop and possible wooden materials on fire, and you also need to control the temperature to be between the melting points of the two materials. Also, the melted aluminum could stick to the steel (I haven't tried so I don't know if this will happen). To me, it sounds much easier to use the approach all commercial reverse vending machines do: crushing.

  • What should the OP do with it after crushing? Still bring it to the recycling plant? – THelper Apr 10 at 7:03
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First, it's pretty easy to remove sugary contaminants from the can right after you drain it. Everything is still wet, and you can just use dilution homeopathy style. If water is an issue in your area,

  • get all the liquid out as best you can e.g. By shaking in sink
  • add just an ounce or so of water
  • cover the hole with your thumb and shake
  • repeat

I am not a big fan of the idea of trying to smelt aluminum in an apartment setting. The biggest problem with melting it is, it is rather aggressive toward oxygen, like "space shuttle solid rocket booster" aggressive.

So you should be doing any aluminum melting inside a glove box, in which you have removed all the oxygen, e.g. By converting it to CO2 by burning something, or replacing with argon, etc. Argon will be less reactive than CO2.

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You should also contact the garbage company and ask if they do automatic separation of aluminum in the waste stream. Many garbage companies do - they use an eddy current separator to fling the aluminum out of the stream. Ask them if it helps to crush cans.

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Contrary to the common mantra of "reduce, reuse, recycle", aluminium is best recycled instead of reused in a household setting. The reason for this is that demand for aluminium currently far outstrips the available quantity in the market, even at theoretically a 100% recycling rate. Thus, repurposing aluminium cans for things such as pen holders actually reduces the aluminium available in the market and leads a greater primary production.

Aluminium has legitimate uses in construction and transportation vehicles due to low weight and high durability, whereas it is substituted more easily for other materials in consumer goods. The best course of action is therefore indeed to reduce first - see whether you can buy drinks in refundable bottles, for instance - and to make sure all aluminium you still have or do still buy goes back into the market cycle, where it can be used for more important applications than pen holders in the future.

When it comes to this second step, by the way, there's not much you can do wrong. Because of its high value, it's extremely likely that aluminium is filtered out of your trash already; recycling rates for aluminium are over 90% in many countries.

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Stand on the top of the aluminum can with one foot and wave arms until the can gives-way and crushes. Begin bagging the cans and keep them in a chest freezer until there is a load big enough to carry to a recycling facility.

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Melting down and casting metals is incredibly satisfying, and bootstraps a whole pile of other possibilities — including ones that can generate an income. It also puts you on (or further down) the path to self-sufficiency.

At the very least, melting down aluminium cans will let you reduce the volume of cans stored drastically. That will buy you some time whilst you are thinking about what to do with the metal that is accumulating.

Unless you have something specific in mind, I would suggest casting them into cylinders — of various diameters — that can be efficiently stacked/stored, and which could then be placed onto a lathe. You can fashion washers, pins, bolts, discs, knobs, axles, barrels, and a myriad of other small components that can be used to make or repair things.

If you're not interested in lathe work, then cast into blocks and thick plates. These can be ground/sanded/machined down into a variety of larger, more "structural" elements — which can be welded/brazed with or bolted to other components you either make or buy.

Regardless of whether your stock is cylinders or blocks, you can always get creative and re-cast them. 3D printers are super-cheap nowadays. Use one to print off more artistic or complex things (gears and the connectors for geodesic domes come to mind). Use the 3D-printed piece as a "master" to create the sand casts that you pour your aluminium into.

Once it dawns upon you that you can shape metal into almost anything, your problem turns into one of having a lack of time to do all the ideas that start flooding into you your head. :)

Even if you never actually end up making anything, you can still exchange the metal at any point in time for cold, hard cash. Might prove useful if the times ahead ever get rough.

Finally, keep in mind that if your apartment complex has stopped its recycling program, then you have a lot of neighbours with exactly the same "problem" as you do. Instead of thinking about what you could do with (say) 1kg of aluminium a month, maybe you should be thinking about what you could do with 10 or 20 times that amount? Efficiency increases, and waste decreases, as you scale up the operations.

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