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homemade kiln shelves

updated fri 7 jul 00


David Hendley on wed 5 jul 00

Around Clayart I'm known as the 'Junk Yard Dog'
because I like to make just about everything I use
in the pottery shop.
I buy kiln shelves.
This is one area where it's better to just pay the
$$ and get what you need.

I have never tried making high fire kiln shelves,
because it seemed like a useless effort. I did,
however, decide to make half round kiln shelves
for my electric kiln, for bisque firing only. For this
I used a fireclay, grog, ground-up IFB mixture.
It was a failure. The shelves developed hairline
cracks quickly. One broke, breaking the ware below
it, costing me more than buying a shelf to start with
would have.
I ordered shelves for the electric the next week.
David Hendley
Maydelle, Texas

----- Original Message -----
From: Tannaz Farsi
Sent: Tuesday, July 04, 2000 11:36 PM
Subject: kiln shelves

| has anyone tried to make kiln shelves or know where i can find some info
| on this? i have loads of cracked silica carbide shelves and want to put
| them to use.
| thanks
| -tannz farsi
| west virginia

Craig Martell on wed 5 jul 00


David is right about buying shelves. Listen to what he's telling you!! I
learned how to make high fire kiln shelves. I was taught by Harry Davis
and a better teacher of this sort of pursuit you will never find. It's
hard work though and requires some special stuff like hammermills and jaw
crushers. You need to make a blend of fireclay and ground, crushed hard
brick. You also need strong angle iron molds to form the shelves. You
have to pound the living shit out of the clay to compact it into the forms
for strength and then comes the tedious smoothing, finishing process. So
take David's advice unless you live in an area that requires the making of
your own equipment.

I'm tired just thinking about this, Craig Martell in Oregon

Nikom Chimnok on thu 6 jul 00

David Hendley writes:

Around Clayart I'm known as the 'Junk Yard Dog'
because I like to make just about everything I use
in the pottery shop.
I buy kiln shelves.

I buy kiln shelves too. And yet, if I were younger and stronger again, I
might try a few more homemade ones. Probalby only for low temp, but I'd see.

What I learned is a materials and forming trick. I started with formula much
like David's: fireclay, grog, ifb, and they broke.

Then I tried adding about 15-20% by volume of rice husks to the mix, and
slop casting it--that is laying it out when it would barely hold its shape,
and had a tendency to slump. I made hundreds of bricks this way, and none
ever broke, so one day I tried a wash tub, perhaps 18'"diameter by 5" high,
as a form. Plaster would have worked much better, but I was just fooling
around, finshing off a firing late at night, so I did this.

It took forever to get dry, being surrounded by aluminum, but I took
advantage of that to pound on it with a rubber hammer, smashing some of the
rice husks, which I considered too big, and compressing it.

I used it as at tub for firing beads and medallions and such--little pieces
that got lot easily. I was amazed how long it held up. Maybe 25-30 firings.
All the firing were up around cone 06-04. The day I finally broke it I knew
I would, as it was too heavy, leaning badly in the kiln, and fired hot. But
even after blowout I kept on using it.

Rice husks made a really fine addition to clay. You can make very large
pieces that seldom break, and they practically fire themselves. I'd been
messing with rice husks for years when paper clay came out. Everyone here
know the clay won't break, but you are left with that texture and it's
pretty unworkable. Still, i found it great fun to play with. Texas ought to
be a place where you could get some--aren't they the world's leading
producer of rice?

Nikom in Thailand