Casting molten aluminum with seashells

Originally published at: Casting molten aluminum with seashells | Boing Boing


Many years ago we found a rock on the beach with a small version of that aluminium cast’s shape clearly embedded in a cavity on the surface of the stone.

Nice to be able to envisage the shape of the shell of the thing that died and whose shell was filled up with mud/sand that later hardened. I’d never really thought about it that hard before, and it ht me immediately when I saw the image in the post.




“What do you mean he doesn’t know how to use the 3 seashells?”


That looks like a fun project. Normal people could try it at home using white metal, which melts at oven temperatures, wouldn’t need the sand mold, and is easier to work and finish. Although, I’m not sure how easy it would be to remove the shell if it hadn’t been heated in a furnace. I suppose you could carefully blowtorch it first, which would take care of the drying too.

I don’t live near large marine molluscs myself, but maybe if I spot a snail shell I will give this a go.


This is such a simple and instant classic, I can’t believe it hasn’t been done before.


I’ve often wondered whether a useful loudspeaker could be made using a seashell as a waveguide. You’d cut the pointy end off and install a tiny driver - perhaps a high efficiency earphone bud. Would it work?


That’s a pretty good idea. Unless you need strength, make casting easier. Choosing the right alloy is important.

A lot of people playing around with melting down aluminum are melting stuff with magnesium, copper, zinc, and magnanese. Great for strength, machining, etc. But not ideal for detailed artistic casting. Silicon is the preferred alloying element for easy casting. 12% silicon or so with everything else below 0.5% and the balance aluminum. Not something you normally make melting beer cans or industrial casting (that uses a different alloy too).

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Kewl. If he’s looking for ideas for other neat things to make an aluminum cast of the inside, would this particular area be of interest?

I mean, painful, sure, but interesting, too, right? :crazy_face:

It might.

Got a spare $60,000?


Would a mild acid not work to simply dissolve it?

Oooooh, shiny. I have some B&Ws, but mine are all boring and square and made of wood.

He smelts sea shells by the sea shore.


Eventually, I guess, but a large shell would take quite a lot of moles.

I dunno though, I’ve never tried destroying shells with either a hammer or acid. In many ways I am like a child

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