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you can use either a silicon carbide or clay graphite crucible..... both have different characteristics... ( more carb uptake in the clay.. i think ?)

- not sure bout in the states... check out your local vesuvius distributer, or RHI, other refractory places

what bout these guys

http://www.budgetcastingsupply.com/

 

I get mine in toronto at canadian thermix... there pricey there

 

 

Greg

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These guys seem to have pretty good prices: http://www.lmine.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=crucibles You can also buy crucibles from McMaster-Carr (mcmaster.com). McMaster used to have decent prices, but last time I checked they had gone up quite a bit.

 

Greg has all the experience over me when it comes to this stuff, but I would swear I've read somewhere that molten iron attacks SiC pretty aggressively.

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I am looking for a place to buy a crucible to make wootz/ melting homemade steel.

 

 

http://www.lmine.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=fire_clay_crucible

 

I have purchased silica and clay crucibles from this place, no problems.

 

Jan

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  • 3 years later...
  • 1 month later...

Jon,

 

EPK with a some extra alumina tempered with mullite and fired as high as you could stand (like, cone 14/2530F or higher) would give you a pretty sturdy mullite crucible. EPK is like 46% alumina, 37% silica , 13% burns away, and some other stuff(data here). You want about 60% alumina to 40% silica in your crucible--Mullite's formula is either 3Al2O32SiO2 or 2Al2O3SiO2.

 

I think Dmitry's recipe is like 2 parts mullite to 1 part kaolin (Link here), but I'm going to go out on a limb and say less powdered mullite and more kaolin is better, just because you get better plasticity. I say this because I would probably throw these on a wheel because I know I can get good compression that way. More Kaolin also means you'll get greater shrinkage and an increased risk of cracking on firing, but I would pre-fire them anyway for strength. This is because when you fire the crucible and you get mullite formation, the mullite forms interlocking needles through the body. It's why real porcelain is so strong.

 

Yet another edit: I noticed this thread from 2007 where Jeff Pringle experimented with a mullite crucible and it burst. I'm willing to be that it isn't a mullite crucible, but rather a mullite-cordierite crucible, especially if it's marketed for glass-making. There's a big difference in melting temps, mullite-cordierite melts above 1400 C, mullite melts above 1800 C.

Edited by Tyler Miller
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It that Kaolin the same that is in commom powder?

 

I know tha clay I use to build my smelting stack, is a Kaolin mix. I wonder if that would be fine to use to make crucibles, by the same formula?

 

Nice ingots Adski!!

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Yes Mark, check with your clay. It was in the recipe Anosov: fire-proof clay.

I used kaolin KOC

  • SiO2: 51,5%
  • Al2O3: 34,5%
  • Fe2O3: 0,54%
  • TiO2: 0,54%
  • CaO: 0,08%
  • MgO: 0,12%
  • K2O: 0,63%
  • Na2O: 0,01%

Charcoal I mills and sifts on the small sieve. (When I added graphite petal, crucibles cracked)

 

I sift crushed crucibles on the coarser sieve. I mix components, add water and make the thick mass.

 

I dry ready crucibles one week, I don't burn it.

 

---

Adam

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do you have some kind of mold to form the crucibles in?

 

and..you don't fire them before using?

 

interesting!

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Yes I have molds to making crucibles.

These molds a bit are altered now. Tomorrow I will paste new pics.

Yes I don't fire them before using.

 

 

dsc00298twc.jpg

 

 

 

 

 

My earlier crucibles with Kaolin, mullite and graphite. These are fired.

Maybe Graphite or mullite was wrong . I don't know.

 

dsc00102db.jpg

 

dsc00103mv.jpg

 

Edit.

 

Last molds:

 

img1223f.jpg

 

img1224pm.jpg

 

img1225rb.jpg

 

img1226ay.jpg

 

---

Adam

Edited by Adski
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