Kiln fired too hot

[littlegoose]

Yesterday was the first time I attempted glaze firing pre-bought bisque ware. I had a group of friends paint cups, and then I was firing them. We used cone 06 glaze. I have a kiln sitter and I've never had a problem. When I opened up the kiln this morning after it had cooled, I found a melted mess. All the cups were just a pool of glaze, no remains of the bisque even present. Now I'm assuming the kiln fired too hot, but the crazy thing was I also had several glazed pieces from pieces I'd thrown and they were perfectly fine. Anyone have thoughts on what happened. I bought the bisque cups from Clay-King. The clay I throw that made it through without issues was cone 6. Also suggestions for getting the melted glaze off the side on the kiln walls?

 

I'll add pics of what I found

 

thanks

[oldlady]

so sorry this happened.  there is a significant difference between 06 and cone 6.  it is a simple mistake too often made.  there is no easy way to clean that mess up.  maybe someone else has some experience in doing it.  i am just sad for you and the others who were looking forward to pleasing results of their own handwork.

talk to clay king where the bisqueware came from.  it is usually low fire clay to go with the low fire glaze.  the clay matures at around 1850 or so F.  you fired it close to 2200 degrees.    

 

[JohnnyK]

You may have inadvertently used a^6 bar in the kiln sitter. The cups were probably a low-fire clay, hence the melted mess. It doesn't look like you used witness cones which would have given an indication of what had happened.

The shelves are probably a total loss. You can try to chisel the melts off and if successful, grind the remaining debris off the shelves. You can probably CAREFULLY grind the melts off the kiln wall, but if that doesn't work, rebuilding the kiln might be necessary.

JohnnyK

[Mark C.]

You will have to get that bottom shelve out-using chisel and hammer-wear safety glasses .

Once thats removed you will need to chip and grind all the glaze off all the brick. If your floor is soaked with glaze considering taking apart the kiln and flipping the floor  so the new side is now up.If you leave any glaze in the brick it will continue melting into the brick every fire until it eats them thru.So grind all the glaze out of the  brick.

As to the shelves it the same deal-chisel then grind all the glaze off the shelves-you may best just starting over with anew shelve .

Mixing up a cone 06 to a cone 6 fire is my guess to what happened. Its like you baked your cookies at at 1500 degrees instead of 350 degrees. 

Ceramics is a technical  experience and small things can really matter this is one of them

Use cones as well as your computer and be with kiln when it shuts off so you can see with cones on whats happening.

Do not mix cone 6 and 06 glazes and wares and clays-they need to be separated in studio-that are NOT compatible .

[Min]

What a nasty surprise that must have been, so sorry for you. In addition to what Mark said you need to check your glaze didn't get on the elements or in the element channels of the brick. Glaze has to come off elements too if there is any that got on them, this would be tricky but you could try a dremel, might have to replace elements in this case.

[Mark C.]

I did not mention the elements as it looked like the mess is all below the last one. But if its on the elements you must do as Min says-it may be easier to replace the element than clean it.