Making castings from recycled aluminium cans

Weigh the cans, take off about 80% for loss due to oxidisation and what you have left isn't worth the hassle.

John

Alan,

The cans do produce vast amounts of dross (oxides) and when the metal is ingoted it isn't the best for pouring - doesn't flow very well into details. You can reduce the dross production by making sure once you have a pool of molten metal, that new additions are plunged below the surface in your crucible - only problem is that if the inside isn't completely dry it can get exiting ! I have a stack of ingots I produced maybe 10 years ago, but tend now to use commercial diesel pistons for critical stuff.

Andrew Mawson Bromley, Kent, UK

You probably know this but,

Small figures are made from a whitemetal alloy, that melts at a low temperature, not much more than boiling water. They are cast into a type of latex rubber mould, usually in a centrifuge. The mould cures around your original, and is flexible enough to be removed easily. This doesn't explain why some of my little railway people have visible moulding lines though- probably made like when we were kids, using plaster of paris half moulds.

My casting book speaks of using molten glass as a cover flux to reduce that kind of thing, too; and I may experiment with trying to keep a layer of CO2 in the top of the crucible, since I have a donated Soda Stream refil. I'm not sure if CO2 will do something worse than oxygen to aluminium, but I'm sure the result will be interesting!

Yes!

This certainly isn't critical stuff; and time spent touching up details with a file will certainly be less than the time it takes her to make a Fymo one!

Thanks,

ABS

Oxidisation is indeed going to be an issue due to the large surface area of the scrap, but I have a few ideas for reducing the amount of oxygen around.

And boy do I have access to a lot of tin cans! My girlfriend volunteers at a scout camp that has a Coke machine, and kids get through a lot of fizzy drinks. In one day she's produced a black bin bag full of crushed cans, and that's just picking odd ones up - they're going to put out a special bin for cans in a few weeks!

ABS

Gave up on them, I can get ali car wheels from the scrappers at £1/kilo

- about £6 for a wheel. The alloy pours well, good detail, and machines well.

The cans... Empty 330ml ones weigh around 14g and will yield 7g of ali per can if you are careful. It takes 850+ cans to make the same amount of ali as a car wheel, that's a lot of stamping on cans, a lot of smoke, and a lot of dross to get rid of. :-(

you may know this.... but you may not... so I thought I had better put my two pennies worth in (prob not even worth that) when you a melting / casting the aluminium be very careful that there is no moisture / water close by a single drop of water in the molten metal will cause a disastrous explosion of the stuff.

you may know this... but I thought I had better say something just encase, best to be safe than sorry!

I had heard this, yes - but I agree - better safe than sorry! Thankyou :-)

Although you should see *liquid nitrogen* meeting molten metal.

ABS

In article , Andrew Mawson writes

I believe you meant that the worker gets exiting, as fast as possible.

o-)