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bisqued pieces, glazes and water...

updated mon 9 jul 01

 

Marianne Lombardo on sat 7 jul 01


Hi Debi

I'm not so sure you have to dry a bisqued piece before glazing it.
Actually, I often dampen the bisque before applying the glaze. I find damp
bisque is easier to brush some glazes on. Perhaps this is technically not
correct procedure, but it has never caused me any problems. I do make sure
the piece is very dry before firing.

Marianne Lombardo
Omemee, Ontario, Canada
email: mlombardo@nexicom.net


> A student of mine asked a question about why you have to *completely* dry
out
> a bisqued piece before reglazing it. I gave an answer...but, I'm sure you

Dannon Rhudy on sat 7 jul 01


>A student ....asked....why you have to *completely* dry out
>a bisqued piece before reglazing it......since glaze has water in it,
why do you have to completely dry your bisque before reglazing ....

If I understand your question, it is: why must a washed pot be
dried before (re)glazing. Is that correct? It is not an absolute
necessity to COMPLETELY dry a piece before glazing, but if
it is not fairly dry, not much glaze will stick to the pot (and some
glazes are fussy and won't stick at all to a wet surface). If the
pot is wet, the glaze that sticks may well be too thin.

If your question referred to glazing over the top of a FIRST
glaze (layering), then you wait for it to dry so that the first glaze
doesn't run off into the second when you dip, or run off if you pour,
or come off on your fingers where you hold it.
The water in the glaze gets absorbed into the bisqueware,
which is why the glaze dries so quickly on a dry pot. The
second layer of glaze will be thinner (the pot has already absorbed
the water from the FIRST glaze- won't hold as much or dry
as fast).

regards

Dannon Rhudy

Karen Sullivan on sat 7 jul 01


Debi...
I always thought that there was a specific range of
porosity to bisqued clay....and if you wash a bisque pot
you have allowed the clay to absorb it's limit of water.
My experience is that if you try to glaze a just washed
bisque pot the glaze just slides off....as the piece is
so saturated there is no tolerance remaining for the
piece to soak up more water....
So let it dry out and try again.
bamboo karen



on 7/7/01 10:09 AM, Debi Rudman at Bonbritany@AOL.COM wrote:

> A student of mine asked a question about why you have to *completely* dry out
> a bisqued piece before reglazing it. I gave an answer...but, I'm sure you
> glaze
> experts would have a better one. So...since glaze has water in it, why do you
> have to completely dry your bisque before reglazing - in other words, what's
> the technical reason it won't work.
>
> Thanks!
> Debi Lampert Rudman
> Ceramics Instructor, duCret School of Art, Plainfield, NJ
> Check out my Canine Art Website
> http://216.155.1.3:591/craftartists/FMPro?-db=craftartists.fp5&
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Snail Scott on sun 8 jul 01


At 01:09 PM 7/7/01 EDT, you wrote:
...since glaze has water in it, why do you
>have to completely dry your bisque before reglazing...


You don't. You just won't get as thick a glaze
layer as you would on a dry piece. So, I think the
real issue here is consistency from piece to piece.
'Damp' is a hard thing to quantify - how damp is
it, really, compared to all your other damp pieces?
'Dry' is a bit more specific - is it dry, or ain't
it?
-Snail

Snail Scott on sun 8 jul 01


At 06:49 PM 7/7/01 -0400, you wrote:
I find damp
>bisque is easier to brush some glazes on.
>Marianne Lombardo


Marianne is right about this. Consistency
of moisture is mainly relevant for dipping
glazes. For brushing, the application technique
is more important, and it's easier to get a
smooth, even initial coat if the bisque is a
bit damp.
-Snail

Avril Farley on mon 9 jul 01


Debi

Another reason for letting the pot dry. If your student is doing multi
layering of different glazes, attempts at dipping or painting on another
glaze when the first is still wet will merely run both layers off the pot
and contaminate the glaze bucket - all too common an occurrence in the night
schools here, when the contents of the glaze buckets are not always treated
with respect due mostly, I suspect, to lack of tuition. Mind you, this can
lead to some startling, and unrepeatable, fired glaze results for an
unsuspecting user!

Avril in the Forest UK