Diane Winters on fri 28 jun 02
Wanda,
Morning, alert, over coffee I had another thought regarding your warping.
Here's something I once saw, in a small factory tile making operation.
After they rolled the slab, they cut the field tiles in two steps using a
set of about 5 thin "wheels" on an axle (actually they had a second
axle/wheel device set at ninety degrees to the other). The wheels were
adjustable to make whatever width tile they wanted. This isn't such a new
idea. But what they did was have the two outer wheels 1/4" or so larger the
inner wheels, so that the inner wheels only cut about halfway through the
slab. The entire group of 16 or so tiles was left connected through the
drying stage, so most of the corners were held in place by adjacent tiles.
I can't now recall whether the tiles were then broken apart before or after
bisquing. I haven't done anything like this myself, but I put it out in
case you can adapt the principle to your situation.
onward and upward in the anti-warping campaign,
Diane
Wanda Holmes on mon 1 jul 02
Diane, thank you so much. I take it from your earlier post that after 8
years, you still have to contend with some warping. In some ways that's
discouraging, but in others encouraging - at least I'm not alone in my
quest. What percentage of warping loss do you consider acceptable? I'd
like to get it down to 10% or less - do you think that is reasonable?
Also, can you say more about your controlled drying? I'm drying to the
"white" dry stage in sandwiches of sheetrock, stacked 4 sandwiches high. I
put strips of scrap clay around the edges so that the sandwiches are
somewhat "sealed" and the actual tiles protected from drafts drying the
exposed edges too quickly.
I agree with you completely on the point of there being no one answer. This
all started when I accepted my first commission (from my sister-in-law,
thank goodness) and had to resign it when I my production efficiency proved
to be downright pitiful. In the months since I've eliminated the visible
warping during the drying stage and overall I have less significant warping,
so I know the improvements I've made are worthwhile. However, the end
result is still grossly unacceptable.
Wanda
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of Diane Winters
Sent: Friday, June 28, 2002 2:36 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Continuing saga of warped tiles / addendum
Wanda,
Morning, alert, over coffee I had another thought regarding your warping.
Here's something I once saw, in a small factory tile making operation.
After they rolled the slab, they cut the field tiles in two steps using a
set of about 5 thin "wheels" on an axle (actually they had a second
axle/wheel device set at ninety degrees to the other). The wheels were
adjustable to make whatever width tile they wanted. This isn't such a new
idea. But what they did was have the two outer wheels 1/4" or so larger the
inner wheels, so that the inner wheels only cut about halfway through the
slab. The entire group of 16 or so tiles was left connected through the
drying stage, so most of the corners were held in place by adjacent tiles.
I can't now recall whether the tiles were then broken apart before or after
bisquing. I haven't done anything like this myself, but I put it out in
case you can adapt the principle to your situation.
onward and upward in the anti-warping campaign,
Diane
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Paul Lewing on mon 1 jul 02
on 6/28/02 11:35 AM, Diane Winters at diane@WINTERSTILEWORKS.COM wrote:
> The entire group of 16 or so tiles was left connected through the
> drying stage, so most of the corners were held in place by adjacent tiles.
> I can't now recall whether the tiles were then broken apart before or after
> bisquing.
The tiles will break apart from each other as they shrink. Just about the
time they get hard enough to not bend easily any more, they crack along the
scored lines. This is a really good way to minimize warping, especially if
you leave that sheet of tiles alone after they crack to dry completely.
This keeps the corners of the tiles from being exposed to the air too much,
and consequently cuts down on warpage.
Paul Lewing, Seattle
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