iandol on thu 24 may 01
A word of caution for all who fire with soda, sodium chloride or other =
sodium bearing salts.
Much of what happens in the kiln depends upon dispersed solid material =
settling on the pottery where it fuses from the heat of the pot.
So it is reasonable to suppose that a quantity of sodium salt will, over =
several firings, accumulate in the kiln wash which is on your shelves, =
melting into it. The more you fire them, the greater the degree of =
fluxing. So even a 50/50 alumina/kaolin wash will succumb to the effects =
of accumulating flux eventually.
Therefore, it makes sense, if you do not wish to be troubled by =
catching, dribbling or the destruction of shelves, to clean your shelves =
regularly, like between firings.
Regards,
Ivor. Redhill, South Australia.=20
Stephen Grimmer on tue 29 may 01
Brian,
Are you using three or four posts per shelf? Most folks find that a
three-point stack eliminates warping considerably.
You could grind the wash off and fire the shelves with the curve up
until they flatten out, too.
Steve
--
Stephen Grimmer
Southern Illinois University at Carbondale
> From: Brian Molanphy
> Subject: Re: kiln wash for salt. Just another chore
>
> ivor's post, which follows, reminded me of a concern i've been meaning to
> post. we use kiln-washed silicon carbide shelves in the soda kiln. because
> the shelves are always placed in the kiln with the same side up (the
> kiln-washed side), they are warped. it would be nice to grind off the wash
> once and for all, flip the shelves, and dust them with alumina each firing,
> flipping as needed in order to flatten them out a bit. but the loose alumina
> blows around in the kiln during the firing, ruining pots. i suppose it blows
> around in our soda kiln and not in our ordinary reduction kiln because of
> increased air circulation during the introduction of soda. anyway, would the
> 'shelf life' be extended by not using either kiln wash nor loose alumina,
> and instead scraping the shelves with another piece of silicon carbide after
> each firing? this would allow us to flip shelves as needed. of course we
> would have to wad the pots, which we generally do already. we have to scrape
> the bottom of the shelves now anyway, which haven't any kiln wash. i'm
> afraid that to continue as we have been will result in severely warped and
> cracked shelves.
> awaiting your erudition, brian
Brian Molanphy on tue 29 may 01
ivor's post, which follows, reminded me of a concern i've been meaning to
post. we use kiln-washed silicon carbide shelves in the soda kiln. because
the shelves are always placed in the kiln with the same side up (the
kiln-washed side), they are warped. it would be nice to grind off the wash
once and for all, flip the shelves, and dust them with alumina each firing,
flipping as needed in order to flatten them out a bit. but the loose alumina
blows around in the kiln during the firing, ruining pots. i suppose it blows
around in our soda kiln and not in our ordinary reduction kiln because of
increased air circulation during the introduction of soda. anyway, would the
'shelf life' be extended by not using either kiln wash nor loose alumina,
and instead scraping the shelves with another piece of silicon carbide after
each firing? this would allow us to flip shelves as needed. of course we
would have to wad the pots, which we generally do already. we have to scrape
the bottom of the shelves now anyway, which haven't any kiln wash. i'm
afraid that to continue as we have been will result in severely warped and
cracked shelves.
awaiting your erudition, brian
> ----------
> From: iandol
> Reply To: Ceramic Arts Discussion List
> Sent: Wednesday, May 23, 2001 11:11 PM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: kiln wash for salt. Just another chore
>
> A word of caution for all who fire with soda, sodium chloride or other
> sodium bearing salts.
> Much of what happens in the kiln depends upon dispersed solid material
> settling on the pottery where it fuses from the heat of the pot.
> So it is reasonable to suppose that a quantity of sodium salt will, over
> several firings, accumulate in the kiln wash which is on your shelves,
> melting into it. The more you fire them, the greater the degree of
> fluxing. So even a 50/50 alumina/kaolin wash will succumb to the effects
> of accumulating flux eventually.
> Therefore, it makes sense, if you do not wish to be troubled by catching,
> dribbling or the destruction of shelves, to clean your shelves regularly,
> like between firings.
> Regards,
> Ivor. Redhill, South Australia.
>
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