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lo-fire glaze problem

updated fri 29 oct 99

 

susan davy on wed 27 oct 99

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I ask this for a friend who does not have a computer:
=22I decorate (brush) on white earthenware bisque, with mason stains mixed =
with
water, + 30=25 frit 3134 for flux...then dip commercial glaze (from Rovin =
Ceramics
SKG, in Detroit, MI), clear, over. Have used this glaze for 4 years...now =
for
the past two months it has been crawling especially over mason purples and
greens....Is there a better way to use this combination of stains/glaze?? =
How
can the crawling be stopped? The glaze is also sometimes looking like =
=22orange
peel=22. I am firing in an electric kiln. Thank you in advance for any =
help.
Cornelia. (sent by Susan Davy, Davy Pottery)

Nguyen Trong Ich on thu 28 oct 99

Susan Davy
there are some reason make crawling
- glaze and body formular are not suitable together you have to search a
glaze Which have thermal expantion coefficient equal with body formular.
- normally ceramic products are glazed 2 times, the first time they glaze
engobe , the second glaze the vitreous coating. Engobe is a glaze have
quality between glaze and body to avoid crawling the coating.
- the temperrature and time in the kiln was not enough .
no way to rescure your material, may be glaze it again with a suitable glaze
formular.
I hope you would have better advice.
Tam Nguyen