deep drop ceramic mold

[KissMyGlass]

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?

[Morganica]

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?

[Dairy Queen]

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