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Alum. casting

Posted: Sat Nov 08, 2008 2:35 am
by irrationalsolutions
i stumbled across several videos on youtube about casting alum. and i was wondering if anyone here has thought about and/or tried it for some diy gear. just a thought but if it works well it would be something to do with the scraps after making stoves.

Re: Alum. casting

Posted: Sat Nov 08, 2008 4:56 am
by dlarson
Yes, I've looked into it but haven't attempted it yet.
The few types I thought might work for me were sand casting, plaster casting, and investment casting.
In junior high I did some sand casting with aluminum. When I was in high school I did some investment casting with silver to make jewelry. I've seen centrifugal casting used with investment casts as well. In college I did some sand casting with bronze.

I've seen directions on how to build the melting furnace with a coffee can, some concrete, a small piece of pipe and a propane torch. I've also seen directions on how to build a crucible, usually steel, but it will contaminate the aluminum. An actual crucible can be bought but they're not really super cheap.

Re: Alum. casting

Posted: Sat Nov 08, 2008 12:14 pm
by zelph
I've thought of investment castings for Tony to use on his suul valves for canisters. I would think that most valves are diecast. Investment casting can be done at home by the DIY groups

Re: Alum. casting

Posted: Sat Nov 08, 2008 3:31 pm
by dlarson
Yeah, I think die casting would be pretty cost effective for stove manufacturers. They probably still machine the inside channels of the valve to smooth out the wall surface though. Then again, maybe they can get away without doing that using a die cast.

Irrational Solutions, someone posted a link to this online machine shop a while ago but I can't find the specific thread.
I've just added it to the Favorite Links category too so it's easy to find later. Depending on what you're thinking of doing this might be another option.

Re: Alum. casting

Posted: Sat Nov 08, 2008 6:54 pm
by irrationalsolutions
what is investment casting. i've seen the sand casting and it looks like it would be a pain but good if you have nothing better to do that day and want some parts that still need to be polished and worked with a bit.

Re: Alum. casting

Posted: Sat Nov 08, 2008 8:50 pm
by zelph
irrationalsolutions wrote:what is investment casting. i've seen the sand casting and it looks like it would be a pain but good if you have nothing better to do that day and want some parts that still need to be polished and worked with a bit.
Try goggling "Lost Wax Process"

Re: Alum. casting

Posted: Sat Nov 08, 2008 9:27 pm
by dlarson
Zelph is correct.
Basically you make a wax replica of the part, pour a plaster mold around it, melt out the wax and pour your aluminum in.
It kind of a one-shot thing because you lose the wax replica and the mold... It's an investment!

Re: Alum. casting

Posted: Sat Nov 08, 2008 10:34 pm
by irrationalsolutions
that sounds like a lot of work. the sand casting sounds easier.

Re: Alum. casting

Posted: Sun Nov 09, 2008 12:03 am
by dlarson
It is more work but it saves some work too. Sand casting generally leaves a much rougher finish than investment casting. So once you've cast your part you'll need to spend more time smoothing it out. Plaster can provide a much smoother finish from the start. Also, depending on the complexity of your part, it might only be achievable through investment casting. Irregular shapes, lots of different edges, fine details, and small items are better done with plaster than sand. That's why we did investment casting for our jewelry.

Re: Alum. casting

Posted: Mon Nov 10, 2008 11:03 am
by zelph
Once you get to a doable product, you then make a silicon mold that's reusable. I've visited a company that made custom belt buckles in limited quantities. They used silicon molds in a unit that had a vaccum system to suck the metal into the molds. First class way to make small quantities of small items.

My brother and I did cast a small aluminum cannon at one time. We used a small ceramic crucible salvaged from a nearby foundry that had just gone out of buisness. Used a 20lb LP tank of gas to melt enough aluminum to create the cannon. FUN!!!!! :D