Firing Clay Busts

[DMCosta]

Hi Everyone, 

My high school students made life-size clay busts using low-fire cone 06 earthenware clay. I'm not new to ceramics but I have never fired a bust. We hollowed them inside out well and created some surface marks with forks inside the sculpture to help. They are currently bone dry and have been in the bone dry stage for at least two weeks and I intend on bisque-firing them this week.  Any suggestions or tips for bisque-firing them in the kiln?

Thanks, 

~Dianna

[neilestrick]

They're probably not very thin or even in thickness, so I'd do a preheat of at least 4 hours to make sure they're totally dry inside, then fire on Slow if you've got a digital kiln. If it's a manual kiln, put the bottom ring on low for at least 4 hours as a preheat, then go all switches on low for 2 hours, all medium for 2 hours, then high till done.

[Benzine]

To avoid the issue, of trying to hollow things, to an even thickness, I just have my students use coils, when creating busts, or heads.  The coils allow them to change the form, better than slabs, and keep it a consistent thickness.

I realize this doesn't help you, with your current batch, but just something to think about, for the future.

Just go with Neil's firing advice, and you'll be fine.  Putting them in the sun, or in front of a source of moving (preferably warm) air, will also help them dry fully.  One reason I like the Winter months, is I can put student projects on the heat vent, to dry them quickly and thoroughly.