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Guest
12-08-2012, 02:29 PM
I need a light material with fairly high thermal conductivity to melt aluminum in. Most guys use steel pipe but that's too heavy for what I'm doing. I've useed thin steel but it burns through too quickly. I need soemthing that'll take high temps with large thermal shocks that will be lighter than 1/4" thick steel pipe.

Crucible size will be around 3-4" in diameter and about 4-5" tall.

DrEntropy
12-08-2012, 05:04 PM
You've got a ceramics expert on-site, fercryinoutloud... toss one onna wheel, fire it without glaze and Cuthbert's th' parrot of yer great aunt!

Whadda ya think gold casting is done with?

tlthorne
12-08-2012, 05:37 PM
That sounds a little larger than a one used by jewelers, they make small clay-graphite ones but they are fairly thick, how about a stainless steel cup? or small pot? s/s pipe? exhaust tip, with a s/s end welded in.

DrEntropy
12-08-2012, 05:39 PM
I know it's larger but suspect it'd work better than what he's tried so-far. ;)

Aluminum melts at relatively lower temps than gold, too. 1200-ish F vs. <2000F for gold. IIRC

Guest
12-08-2012, 05:55 PM
It won't withstand the shock Doc. Even with raku clay with a much slower temp rate gives us trouble much less a full-blast furnace. I wondered about stainless if it will withstand multiply firings at a minimal thickness. I don't like stainless' thermal conductivity. I wonder about copper? I may just have to use steel. Livin' on the edge here as my process/technique is all uncharted territory. Gotta fab up all my equipment. Biggest problem is, if a cruible fails on me my goose is cooked, literaly...

tlthorne
12-08-2012, 05:59 PM
the aluminum will erode the copper quickly, they dissolve copper in molten aluminum when alloying.

George_H
12-08-2012, 08:23 PM
Stainless should work well at 1200. We fire waste enamel at work in SS mixing bowls up to 1600. We use them many times over and they are cheap.

Guest
12-08-2012, 09:22 PM
How thick are they George?

George_H
12-08-2012, 09:49 PM
Just regular mixing bowls. Thin and cheap. You could use pet bowls for smaller stuff. Assuming that you are using an electric kiln, you shouldn't have a problem.

weewillie
12-09-2012, 12:25 AM
would something like this do Billy,
https://www.backyardmetalcasting.com/furnace.html

Guest
12-09-2012, 05:02 AM
Well, yes and no. My furnace is very similar (large feed bucket) however; his crucible is too heavy and is grabbed from the top. I will have to make a vice-grip like clamp with a heat shield to grab it close in from the side. I may still have to go with steel. I just hate to use something that heavy.

Banjo
12-09-2012, 09:35 PM
I'd reccomend inconel (Spelling?) but that ain't light either. nor is it cheap.