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my workhorse kiln is a Cress front-loader, with 8" shelves. it has pyrometer and infinite switch, but not digital controller. last week i forgot what the hell i was doing, and let it heat up to about 2200F. the glass ran off the shelf in the back and made some fairly deep holes in the floor bricks, in the back. i threw the shelf away.

so, do you think i should try to remove the glass before patching the holes, or just patch the holes, with the glass still there? i've got kiln cement here that i can mix up. i'm concerned that the glass might continue to erode these depressions and make the problem worse. the holes are about the size of a 50 cent piece, and maybe a half inch deep.

i run this kiln several times a day, nearly every day, and have been doing so for over six years. i'd like to fix this problem in the best way. thanks for any ideas and insights. (PS -- if it makes any difference, it was BE.)

I'd get the glass out before patching. Brock

The glass will keep eating away at the brick. Remove the glass before you patch the whole. The problem with the cement is the the brick and cement might expand at different rates. Unless the bottom of the kiln is showing when you remove the glass it might not need to be repaired. Can you put a shelf over the area?

i can see if i can get the glass out of there. it might not be easy to do so, but i will see.

stuart, are you suggesting i put kiln cement in the holes, and also put a shelf on the bottom of the kiln?
or, forget the kiln cement, and put shelf on floor of kiln, after removing whatever glass i can get rid of?

i dont mind putting a shelf on the floor of the kiln. that would be OK ... i've got a lot of shelves for this kiln, because i do a lot of loads.

i think the kiln cement does expand/contract at a different rate. i've used it to patch some crumbly areas on this kiln, and it seems that this is the case.

I would forget the patch and just put a shelf over the hole. The patch is good to glue back parts of the brick in a whole. If you put a large glob of it, it will just eventually pop out.

You must dig the glass out. The glass will erode out the brick.

For future reference.. put kiln wash on the bottom of the kiln to catch glass drippings.....

i did have the floor coated with kilnwash, but this incident was very hot, and the glass just burned thru.

thank you for your help.
i'll do as you suggest.
kitty

Stuff fiber blanket in the holes. You can also put down a thin layer of sand to protect the floor of your kiln.

ch

Are the bricks loose or cemented together? This is just a thought, but if they are loose, you might be able to pry them out and flip them over. They insulate well enough that even if you can't get all of the glass out, the exterior side of the brick shouldn't get so hot that it would continue eroding. It depends on the extent of the damage, and the way the bricks are packed in there... but it might be possible.
-elin

My take is to dig the glass out and fill the gap with a castable refractory cement. I think it is best to replace the missing insulating brick with a similar material.

I fixed a pottery kiln this way once and as far as I know it is still functioning fine.

You could put sand on the floor so the glass just gets stuck in the sand.

thanks Bert.
i certainly hope i dont do something this foolish again. it's a first in six years.

i'll see about getting the glass out tomorrow.
egad.
what a mess.
wish i hadnt done this.
TY4 your help.
kitty