Firing Fiber Board

[Lori]

I just bought some 1" thick fiberboard. What will happen if I just use it to slump without firing it separately first?

Also, if necessary to fire it first to get the binder out, what temp should it be fired to? I've seen 1480 and 1200 both. Do you just ramp the kiln up as quickly as possible to the appropriate temp and then cool down as quickly as possible? How much black smoke does it actually give off?

[Bert Weiss]

I just bought some 1" thick fiberboard. What will happen if I just use it to slump without firing it separately first?

Also, if necessary to fire it first to get the binder out, what temp should it be fired to? I've seen 1480 and 1200 both. Do you just ramp the kiln up as quickly as possible to the appropriate temp and then cool down as quickly as possible? How much black smoke does it actually give off?

Fire it up first. First it will turn black as the binders heat up and smoke. When it turns white it is fired out. I prefer leaving while it is burning out. It can not be heat shocked so don't worry about fast heating or cooling. The smoke is smelly and unpleasant not killer.

I recommend firing to the temp you plan to work at so any issues of expansion or shrinkage will be dealt with before you use it.

[Lori]

How long should I hold it at the peak temperature before it turns white and burns out?

[Brad Walker]

How long should I hold it at the peak temperature before it turns white and burns out?

Hold it until it burns out. You'll see it turn white again. That could be a few minutes, or it could have happened already.

How long depends on the particular brand and board.

And make sure you vent the kiln when you fire the board. Prop the lid open an inch or so until you get over 1000F. And leave any portholes open the whole time.