Vince Pitelka on tue 21 nov 06
"> Try fewer coats. Apply a THIN coat and let dry throughly. Then apply
> another THIN coat and let dry throughly. I've learned to stop after
> three coats. More than that and the terra sig flakes off and does all
> manner of nasty stuff."
I think it is a question of the terra sig preparation, and the bisque-firing
temperature. If the sig is properly prepared, and thinned to 1.15 specific
gravity, then you can apply quite a few coats, one right after the other as
soon as the previous one is no longer visibly wet, and then polish after the
final coat. I have applied eight or ten coats of properly-prepared sig with
no problems with flaking or cracking.
Most of our terra sig work is bonfired, and we don't want to loose any of
the shine, so we generally bisque-fire to only cone 018. Bisque-firing even
up to cone 010 or 08 will increase the likelihood of cracking and flaking.
In that case, I'd go with Deb's advice above.
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
Deborah Thuman on tue 21 nov 06
Try fewer coats. Apply a THIN coat and let dry throughly. Then apply
another THIN coat and let dry throughly. I've learned to stop after
three coats. More than that and the terra sig flakes off and does all
manner of nasty stuff.
Vicki Hardin on wed 22 nov 06
I think the fit between the clay the sig is made of and the clay in the
piece is also a factor because I have noticed that if I fire the same sig on
a low fire clay with the exact same approach for application I get the
cracks while I don't on a cone ten clay body. This is not a problem for me
because I this information when I want the cracks because I like the raku
effect it gives.