cone 6 porcelain

Hi Everyone,
I fired a piece of Laguna Frost cone 6 porcelain using my regular cone
6 stoneware glaze and the glaze ran. It doesn't on stoneware. Does
anyone know if there is something about porcelain that would cause a
glaze to run? It was the first time I fired porcelain. Do you have
to use a different formula glaze even though it's a cone 6 porcelain?
My glazes are rated cone 5-6.
Thank you for any help on this issue.
Sandi

On 8 Apr 2007 16:12:23 -0700, "Red Deer"
wrote:

Hi Everyone,
I fired a piece of Laguna Frost cone 6 porcelain using my regular cone
6 stoneware glaze and the glaze ran. It doesn't on stoneware. Does
anyone know if there is something about porcelain that would cause a
glaze to run? It was the first time I fired porcelain. Do you have
to use a different formula glaze even though it's a cone 6 porcelain?
My glazes are rated cone 5-6.
Thank you for any help on this issue.
Sandi

Someone else will have to explain the chemistry of it, but I've seen
warnings before not to use a particular glaze on porcelain due to
running. My guess is that the flux in the porcelain can result in
additional fluxing of the glaze, so a glaze that is fairly fluid on
stoneware becomes even more so on porcelain.

deg