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tile - majolic and warping

updated sat 31 aug 96 on sun 18 aug 96

I don't think you're disagreeing with me as much as you think. When I said
that majolica decoration was on the surface, I didn't mean it was like china
paint, a separate layer on top of the glaze. But it is applied to the
surface of the glaze, and while it does sink in and become part of the glaze,
it is not as protected from abrasion as a decoration that is under the glaze,
all the way through the glaze, or all the way through the tile. My point was
that wearing off a relatively thin layer of glaze would obliterate the
And, yes, many people use a majolica technique at cone 6, but majolica is
traditionally done at a lower temperature than that. This fellow did not
specify what temperature he was using, but I assumed about cone 04, which I
would be reluctant to use on a floor, especially if I didn't know the
composition of the glaze.
I hope that clarifies it.
Paul Lewing

LINDA BLOSSOM on mon 19 aug 96

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Hi Paul,

Ok then if majolica is near the surface - ever wonder how near or how much of
the glaze is impregnated with the stain? Hmm time to get out the loupe tool and
break a tile!

Ok I've done it. I used a grinding saw to give me a crosscut of a tile. The
stain penetrated anywhere from 1/4 to completely through the glaze. It depended
on the application. The places where it was 1/4 to 1/32 of the way through the
glaze was a very thin layer of stain. The places where it penetrated completely
was a heavier but not heavy application. This was fired at cone 6. If you have
a tile fired at 06 could you repeat this and let me know the results?

As far as temperature, I don't know why anyone would use a lowfire tile on a
floor for any reason. Well, maybe if they are unglazed, deep burgundy
terracotta tiles that are so beautiful that you couldn't say no. Otherwise, I
stick to cone 6+ for all surfaces, especially functional areas like floors and

Ithaca, NY

Ithaca, NY
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------ =_NextPart_000_01BB8DC5.9519F280-- on tue 20 aug 96

Hi, Linda,
Anything for science, right? I don't work at cone 06 so I don't have a tile
like that to cut. Maybe somebody else out there would care to sacrifice a
tile (or a pot) to research?
I don't know why anybody would put a low-fire glaze on a floor either. But I
think I know those burgundy unglazed tiles you're thinking of. They are nice.
But, there again, the color on those goes all the way through, so they might
be OK on a floor even if they are not fired very high.

Cathy Nelson Hartman on tue 20 aug 96

Just for the tile record-virtually all floor tile IS low fired. Many are
lead base glazes-no problems I don't think. The reason for low firing is
to avoid warpage. And earthenware is still strong when applied to a
concrete subfloor. Check it out at your friendly commercial tile
manufacturer. You can search on Excite for "tile", "American tile
manufacturers", "ceramic tile", etc. to connect to more info than you can
imagine. I can supply some URL's if needed.

Walter Hartman

Hartman Pottery
1600 Willowwood
Denton, TX 76205
(817) 382-1083

e-mail: on thu 22 aug 96

I don't know about most floor tile being low-fired. Sure the unglazed
Mexican paver type floor tile is, but a lot of floor tile is what the tile
industry refers to as porcalain, although they mean something different by
that term than potters do. But certainly it is fired higher than, say, cone
One of the problems here is that tile manufacturers will tell you very little
about their processes, and nothing about their glaze recipes.
But I seriously doubt if there is much lead glaze used on floor tile. For
one thing, nobody wants to work with it, even in third world countries. And
for another, lead is about the softest glaze material you can use, and so
totally inappropriate for floors for that reason, and also because lead
glazes retypically glossy, and so inappropriate for that reason as well.
Paul Lewing, Seattle

Don Sanami on fri 23 aug 96

Dear all, Of the hundreds of tiles we have made,nearly all were
low-fired.Many in hastily cobbled kilns.often quite close to thew source
of wood and clay/ Of major importance is the sub-strate.Stability is all.
Although past bedding usued clean,screened sand,we have used a thick
bedding of non-drying tile cement. Usually these tiles are unglazed and
depend upon TLC with deep coats of wax,applied over time. Fogg Museum,at
Harvard C.,Cambridge,Mass.,has an entrance floor of tiles in which the
wax has so deeply penetrated,one is almost afraid to step forward for
fear of falling in to the deep red pool. Whether high-fired or
low-fired,all wood-fired clay depends upon deep polishing and time to
bring out its true beauty. Isao advises me thattiles to be walked upon as
well as wall tiles,require at least 10% of a good medium as well as
screened grog. As in mmost ceramic processes,careful screening is an
absolute necessity to assure uniformity of particle size. Don& Isao

Carl Ross on sat 24 aug 96


I would be very interested in those URL's. that is a relief to me as the
tile we installed was red and the same tone as the samples I fired to ^04.

Much Appreciated,

Carl in Phillips