David Hendley on thu 20 jul 06
----- Original Message -----
>i have access to a few thousand very inexpesive firebrick (about 20 cents a
>piece) the names are star, >grefco, vega. i am told they are roughly 95-98%
>silica with virtually no alumina. they have a rating of >3060F . they have
>never been used. we got them from a steel foundry that went belly up. my
>question >is, would they work to build a woodfire kiln?
In a word --- NO.
High silica bricks are made to used in continuous (always on)
kilns. Although they can withstand very high temperatures,
they must be heated and cooled very, very, very slowly.
Normal temperature rise in a pottery kiln, even a long slow
firing is too much, and they would crack and eventually crumble.
The area around the firebox, where the flame enters the kiln
wouldn't stand a chance.
David Hendley
Maydelle, Texas
david(at)farmpots(dot)com
"EXTRUDE IT! Getting the Most From
Your Clay Extruder" available at
http://www.farmpots.com
Paul Herman on thu 20 jul 06
Brad,
In a word, no. You want bricks with at least 40-45% alumina content.
High silica bricks are meant for continuous duty, ie. you get them
hot and they stay hot through their working life. Repeated heating
and cooling (like in a potter's kiln) will make the silica bricks
crack. Look for Empire, Clipper, Diablo, Yukon.
best,
Paul Herman
Great Basin Pottery
Doyle, California US
http://greatbasinpottery.com
On Jul 20, 2006, at 12:19 PM, brad neu wrote:
> i have access to a few thousand very inexpesive firebrick (about 20
> cents a piece) the names are star, grefco, vega. i am told they are
> roughly 95-98% silica with virtually no alumina. they have a rating
> of 3060F . they have never been used. we got them from a steel
> foundry that went belly up. my question is, would they work to
> build a woodfire kiln?
>
> thank you
> brad
>
Hank Murrow on thu 20 jul 06
On Jul 20, 2006, at 12:19 PM, brad neu wrote:
> i have access to a few thousand very inexpesive firebrick (about 20
> cents a piece) the names are star, grefco, vega. i am told they are
> roughly 95-98% silica with virtually no alumina. they have a rating of
> 3060F . they have never been used. we got them from a steel foundry
> that went belly up. my question is, would they work to build a
> woodfire kiln?
Might work, especially if it is large and fired slowly. Silica brick
are touchy when fast fired. But we built a salt kiln at the U of Oregon
with them, and once the salt glazed them, they did not suffer further
attack and the kiln went a very long time without replacement. If I had
a stash of them, I would place them in someone's salt/wood kiln and see
how they performed over several fires. This is all to encourage you to
try them(after testing).
Cheers, Hank
www.murrow.biz/hank
brad neu on thu 20 jul 06
i have access to a few thousand very inexpesive firebrick (about 20 cents a piece) the names are star, grefco, vega. i am told they are roughly 95-98% silica with virtually no alumina. they have a rating of 3060F . they have never been used. we got them from a steel foundry that went belly up. my question is, would they work to build a woodfire kiln?
thank you
brad
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Ivor and Olive Lewis on fri 21 jul 06
Dear Brad Neu,=20
Sounds like a bargain but beware. These will be made from Quartz Sand. =
Being almost pure quartz they will retain all the characteristics of =
that mineral.=20
During heating Alpha Quartz will change to Beta Quartz. This changes the =
O-Si-O angle and the structure from a distorted hexagon to a regular =
hexagon. Volume increases with a change from Alpha to Beta Quartz. This =
reverses on cooling. The "Quartz inversion temperature" is stated to be =
573 deg C. The stress created cause the bricks to crack. Dunting at =
work, wholesale ! !
In industry, kilns constructed from this cheap refractory are never =
allowed to cool below about 650 deg C. This stops the kiln from self =
destruction. Which is why Coke producers for steel making detest Stock =
Market Crashes, Slumps and Depressions.
So...Caveat Emptor....
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Andy Misner on fri 21 jul 06
If they are made of a Fused Silica they will work for you.
Andy
www.indfirebrick.com
On Thu, 20 Jul 2006 12:19:32 -0700, brad neu wrote:
>i have access to a few thousand very inexpesive firebrick (about 20 cents a=
piece) the names are star, grefco, vega. i am told they are roughly 95-98%
silica with virtually no alumina. they have a rating of 3060F . they have
never been used. we got them from a steel foundry that went belly up. my
question is, would they work to build a woodfire kiln?
>
> thank you
> brad
>
>
>---------------------------------
>Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+
countries) for 2=A2/min or less.
>
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