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(how) can you glaze over commercial tile

updated thu 29 oct 98


Janet H Walker on mon 26 oct 98

I was talking with someone the other day about a project that involved
doing some decorative tiles to go with a background of commercial black
tiles. One of the ideas we kicked around was whether you could just
decorate the commercial tiles and refire them. So I checked with Paul
Lewing and the answer was a hearty "it depends". I thought perhaps
some other people would be interested in knowing a big more about this
issue. So, here 'tis.

Date: Fri, 23 Oct 1998 21:20:32 +0000
From: Paul Lewing

Janet, You can send this on to Clayart if you feel like anybody would
be interested, and I'll try to answer your questions, but the real
answer is "It depends". You never know what cone a commercial tile
was fired to, and the distributor will probably not be aable to tell
you. Also, most tile is now made in fast-fire roller-hearth kilns, in
which the firing cycle is incredibly short, so cone number doesn't
even really tell you much, because the firing cycle is so different
from what we do.

You can use china paint on almost any commercial tile and refire it
without changing the original glaze. Is this what you mean by "a
normal overglaze"? But if you refire to somewhere close to the
original firing temperature, you may run into problems. Sometimes the
original color changes, sometimes the surface (from matte to gloss,
for instance). There is no way to predict. You must test, not only
each brand of tile, but each color of each brand.

> Seemed like it would be easier to just buy a bunch of the same black
> tiles and decorate them. Same surface, same profile, etc.

This could be a nightmare. I did a job like this once that I still
refer to as "The Pandas from Hell". Black china paint on a white tile
did not match the black glaze on the other tiles. One coat of white
c.p. did not cover and two coats flaked off. White opaque cone 04
glaze covered the black, but the black became Navy blue. I ended up
starting with a white glazed tile and glazing the backgrounds behind
the P's from H black.

I'm making this sound impossible, but it's not. In fact, I have a
good friend who makes a real good living doing just this. But it's
not simple, and in the last few years it's gotten more complicated,
because of the roller-hearth firing. By the way, the tile produced on
those production lines is nowhere near the quality that used to be
produced, but American industry doesn't care about that.

Rob on wed 28 oct 98

try porcelaine 150. a water based paint that gets fired in your oven. it
won't hold up under food or heavy traffic, decorative only.