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Picture of Cast Aluminium Gears
This instructable will show you a technique of casting known as lost foam casting, to create aluminum gears. The gears in this instructable do not have any real purpose other than decoration, but with more time and patience, you could create gears for actual use on something. Please vote and favorite!

Step 1: Watch the Video

I made a full tutorial on creating these gears. I recommend watching it, as it goes a little faster than reading this instructable, and goes into further detail.

Link: https://www.youtube.com/watch?v=ALU6_bUq9qo

 
laffinm (author) 11 months ago
Well, when the molten aluminum, which is very hot, first touches the foam, the foam rapidly disintegrates and the aluminium fills the mold. You might think that the sand would cave in directly after the foam is gone but actually the fumes of the burned foam slightly harden the inside walls of the cast, and they stay firm enough for the metal to full it completely. I hope this helps a little bit, as it can be very confusing.
mkovtchega11 months ago

I don't know pretty much anything about casting, but I want to try it. So I don't really understand how the molten aluminum takes the gears form?

gasperi1 year ago

How many cans do you need to make something that size?

pfred2 gasperi1 year ago

I've cast cans into ingots and it takes quite a few cans. The main trouble with melting down cans is how thin they are. Being so thin they tend to oxidize more than they melt. Oxidized metal is not the nice shiny stuff that you're looking for. I find that submerging the cans to melt them helps out a lot, but that has its own hazards doing it too.

The other thing to note is that cans are pure aluminum. Pure aluminum is not the best casting alloy of aluminum, it isn't an alloy at all. You can alloy your pure aluminum with some zinc and have a better material.

If you want to add zinc to your alloy, remember that pennies are made from zinc, with a copper coating, which can be removed any number of ways. And no, its not illegal to melt pennies down for the zinc, the law about messing with money is very specific, and indicates that defacing them to change their value is illegal (making a silver dollar out of a quarter) but turning them into something that is not money is perfectly fine.

You would have to add quite a bit of zinc to reach the ratio that Zamak is. Diecast metal is mostly zinc. I think that would be more economical material to use than pennies.

This is exactly what I was going to post: cans are pretty cruddy to cast with. A better solution would be to go to craigslist and find an aluminum block lawnmower in the free section and haul it off. Yes, it does require a lot of work to disassemble and clean (clean material = less crap to skim), but it is a casting alloy and will be night and day in difference in your results.

laffinm (author) 1 year ago
About 20-30 was enough for this project. You want to have a little more than you need just in case. Also, if you crush the cans into a small ball, they will produce more liquid.
baecker031 year ago
collect hard drives, good aluminum for use.
laffinm (author) 1 year ago
I actually did poke a few vent holes but didnt bother to write about them. Sorry about that :)
neo716651 year ago
On larger items it helps to put vents to allow gas and air escape. You still sometimes end up with voids but they often help eliminate them.
babaguru1 year ago
I wonder how heavy it would be they look pretty chunky

My uncle used to cast replacement Studebaker parts like door handles from melted down pennies, but pennies were 100% copper back then. He used the lost wax process then would clean & polish them up and send them out to a plating company to have the parts nickel then chrome plated.