WarmGlass.com

I have a very deep ceramic mask mold. I have fired this mask twice. The first time I didn't quite know what to look for when I peeked into the kiln, so I know I didn't leave it in long enough. I took it to 1175 for 30 min. I fired it a second time, took it to 1250 for two hours, it still hadn't filled in at the mouth and nose area, so took it to 1350 for another hour and a half, it still didn't totally drop into the nose and mouth. I finally had to go to bed. Should I have waited even longer, hotter, what?

What is your entire schedule? What is the size and depth of the mask? How thick is the glass blank? Does the mask have openings in the bottom/sides of the nose and mouth or is it solid? Is the mask bottom against the floor/kilnshelf or elevated? What colors/kind of glass are you using?

Hrd to tell if a longer schedule will help without knowing a bit more about what you are working with?

Is there a hole for escaping air, or is your glass sitting on trapped air in the nose/mouth?