Lili Krakowski on mon 22 jun 09
>
Centa asks:
"Does anyone have experience refiring majolica glaze (ala
Arbuckle) to get
> rid of pin holes or areas of the surface clay body where the
> glaze didn't
> absorb at all! And why would that be? Why would the glaze not
> adhere?"
There are two problems here, not related as far as I can tell.
Pinholes. If a "good glaze" one that has been tested, one that
comes from a reliable source behaves poorly there is a reason
beyond the glaze recipe itself.
There may have been an error in transcription of recipe, there
may have been a weighing out error, it may be that you got a new
bag of material x and it is a bit different.
It may be that your bisque fire was not hot enough--it may be
that your glaze body is a bit different. It may be you bisqued
too fast...It may be there was dust on your ware. In opacified
glazes a small error, a tidge too much of opacifier can be the
cause. And as others said too thick a coat of glaze and not long
enough a glaze firing....
As to non-adhesion. That could come from dirt on the
bisque--esp. oily stuff; a bit of mayo (DON'T eat in the studio)
a dab of hand lotion....It also can come from overpolishing a
tight body as it is being trimmed. Get back to us if the
adhesion problem is in a specific area....Overpolishing also can
cause crawling.
Or why I repeat with boring consistency: Always test your new
batch of glaze before committing a lot of pots to it. Have three
or so bodies in the shop so as to have test tiles from different
bodies to test glaze recipes on as they come in.
And, yes. Humidity does affect the weight of materials.
Different materials differently. But if you are in the same
climate all your materials have been affected before they got
into your glaze...so maybe if you went from a bayou to the top of
the Rockies you might have to adjust a recipe....but I have
potted in diverse climates and not seen perceptible differences
in results.
Please do let us know what results you get from diverse remedies.
Always eager to learn
Lili Krakowski
Be of good courage
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