Cracked Kiln Shelf

[Saturations]

I recently did a long thick pot melt with great success on the glass, but my shelf cracked during cool down.  any idea why that would be??

[Anonymous]

Sorry to hear that.

If none of the glass stuck to the shelf it was probably thermal shock.

What kind of kiln and what was the schedule?

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Paul
FusedGlass.Org
Helios Kiln Glass Studio
PaulTarlow.com

 

[Saturations]

1000 1000 15 min

250 1100 15 min

1000 1700 90 min

9999 1500 45 min

9999 950 180 min

12 800 15 min

24 700 10 min

120 100 0 min

 

[Anonymous]

A couple more questions:

1) Did the glass break too – or just the kiln shelf?

2) How do you know it broke on the way down?

3) Were you firing right on the shelf – or fiber board/fiber paper?

Paul

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Paul
FusedGlass.Org
Helios Kiln Glass Studio
PaulTarlow.com

 

[Saturations]

The glass did not have any sign of the cracked shelf under it – no creases etc. I was using shelf paper 1/16″ under the glass and around the stainless molds. I assume it cracked on the way down because there was no healed marks on the bottom of the glass. I did discover a crack forming on the 6×6 piece but not the other one after a few days.

I may have been aggressive taking the glass out of the the stainless dam (which I did in the kiln and on the shelf).

The shelf was thinner than most (I got it second hand – made in taiwan with riddges on the bottom).

[bhawbaker]

Same thing happened to me doing the kiln pressed glass project.  I normally have the shelf on 1/2 inch posts to even the heating, and I should have put the shelf directly on the kiln floor.

 

But all is not lost!  I just cut up the broken shelf with a tile saw (using the tile blade) into 1″ strips to use as dams, holders for screen melts, etc.

 

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