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Aluminium foundry

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Dr. Shark

Sun Jan 28 2007, 03:49PM

Registered Member #75 Joined: Thu Feb 09 2006, 09:30AM
Location: Montana, USA
Posts: 711

I was only trying to make a very small nozzle, about the size of the basic "Estes" rocket motors. If more people are interested in talk about rockets, maybe we should start a new thread?

Tetrafluoroethane

Tue Jan 30 2007, 12:58PM

Registered Member #127 Joined: Fri Feb 10 2006, 03:36PM
Location: Cincinnati, OH - USA
Posts: 44

I have always found that for lost-wax casting it is better to evaporate the wax out of the mold at high temperature before attempting your cast. If you cannot get the mold up to a temperature high enough to evaporate the wax you might try lost-foam casting instead. I believe you can leave the foam in the mold before pouring in the casting metal (since foam is mostly air anyway).

Carbon_Rod

Wed Jan 31 2007, 06:41AM

Registered Member #65 Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155

Propane fired crucibles are fast and cheap.

The problem is Al alloys (cans etc.) often pour like cottage cheese even with the right slag. No good for fine work as the top 10" of the casting may have pits, or hot tears.

cheers,

Madgyver

Wed Jan 31 2007, 01:32PM

Registered Member #177 Joined: Wed Feb 15 2006, 02:16PM
Location: Munich, Germany
Posts: 214

Carbon_Rod wrote ...

Propane fired crucibles are fast and cheap.

The problem is Al alloys (cans etc.) often pour like cottage cheese even with the right slag. No good for fine work as the top 10" of the casting may have pits, or hot tears.

cheers,

That's because that alloy isnt meant for casting. Aluminium cans are pressed into shape.

Look for engines at your local scrap yard. The whole block or the zylinders are often made out of good aluminium alloys, which cast very easy.

muciek man

Wed Jan 31 2007, 06:48PM

Registered Member #163 Joined: Mon Feb 13 2006, 01:55PM
Location: caledonia ohio
Posts: 22

if any one is intrested in building an aluminium foundry in a 5 gallon bucket
check out lindsaybks.com. they have lots of old out of print books and even tesla coil stuff.
the 5 gallon bucket foundary is under the gingery books section and labeled build a charcoal foundary.

Dr. Shark

Thu Feb 15 2007, 08:40PM

Registered Member #75 Joined: Thu Feb 09 2006, 09:30AM
Location: Montana, USA
Posts: 711

Here is one of the parts I made, I finally got a picture of it

Banana Man

Fri May 04 2007, 12:07AM

Registered Member #625 Joined: Tue Apr 03 2007, 08:05AM
Location: Hollyweird, FL 33020
Posts: 18

I have a bunch of 40mm grenade casings waiting to be cast into half of an aluminum/brass chess set. They're obviously made of a tough alloy and appear to be swaged or extruded into shape. After I melt them down and, with my luck, realize it's a bad alloy for casting there must be another metal like lead that can be mixed with aluminum to make it fill better and prevent bubbles. Perhaps vibrations or vacuum might work if I can work quickly enough.
I wish I had this thingy. http://www.koslow.com/te-3000.html
Actually that's more of a doodad.

Chris

Fri May 04 2007, 12:53AM

Registered Member #8 Joined: Thu Feb 02 2006, 04:34AM
Location: Harlowton, MT, United States
Posts: 214

Yes, vacuum casting could lower the melting point, reduce oxidation, and eliminate bubbles. Those are all good things.

Banana Man

Thu May 10 2007, 05:37AM

Registered Member #625 Joined: Tue Apr 03 2007, 08:05AM
Location: Hollyweird, FL 33020
Posts: 18

Huzzah! I suppose I could cast them in a cylindrical container with a flat, cork gasket lid. Then immediately after pouring set off a fireball to heat the air then as it cools and tries to fill the space it will seal the lid and create a vacuum. I imagine this to be the simplest way as long as proper safety protocols are followed. Hydrogen (not mixed with pure oxygen) would rationally make the best vacuum since it produces steam then water instead of gasses and would be a good motivation for me to make my newly invented type of electrolyzer, at least I dont think anybody has ever made one that works like mine. I dont have space in the barraks to make a bulky vacuum casting machine so wish me luck with my crazy go boomy hydrogen/steam vacuum of doom.

Chris

Thu May 10 2007, 01:31PM

Registered Member #8 Joined: Thu Feb 02 2006, 04:34AM
Location: Harlowton, MT, United States
Posts: 214

Cork gasket? Wouldn't something that can withstand very high temperature be more appropriate? Maybe a very thin gold wire could form the gasket, or something like that?

A gas that reacts to form a solid would be most appropriate for this; just purge the vessel with some pure oxygen or chlorine before starting, and its reaction with the aluminum should gain this result. Good luck, and be careful.

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