fusing glass how many times

[dawn]

I have just opened my kiln and the piece of glass that I was slumping was in pieces.  I am so disappointed.   

The piece had been in the kiln twice as well as being slumped (so 3 times in the kiln in all).   Does it make any difference how many times the glass is fused?  If it does what should be done to make sure I do not have the same problem again?

Thank you oh wise ones, I know you will be able to help.

Dawn

[Paula]

What type of glass are you using?
Bullseye glass can be fused many times, but float seems to be limited, but I think that has to do with devitrification.
The cracks, are the rounded, or sharp cracks.This will show if they cracked on the ramp up, it will be rounded, as they will have cracked then melted. Whereas a sharp crack is during the cooler temps.

This is quite a good site which answers almost anything you can think of.
http://www.warmglass.com/phpBB/index.php

If you have different types of glass it could be incompatibility.

[Dennis Brady]

In theory, you can fire again at the same schedule previously fired at, but my experience has consistently been that is needlessly dangerous and each consecutive firing is safest if ramped at a slightly lower speed.  What ever ramp speed you fired at before, fire just a little bit slower on subsequent firings.

[dawn]

Thanks for replying.

I am using Spectrum 96 glass.  The cracks are sharp and seem to radiate from a point in the middle of the piece.  I fired it using the same schedule each time.

Dawn

[Zeldazog]

What Dennis said - basically, the thicker your piece, the slower the ramp.  Also, depending on what you fused together, your piece might now be of uneven thicknesses of glass - so again, slowly, slowly.

[Dennis Brady]

Dawn,
Go to this website:
www.glasscampus.com
click on the flashing link for "Kilnforming Kindergarten".  It's a PDF so take about a minute to open.
Download it.  You'll find a lot of helpful material there.

[Zeldazog]

Thanks for the tip sheet, Dennis, another one to be downloaded and added to my glass bible.....

although, you might want to check your calculation for melt quantities.....?

[dawn]

Thank you, thank you, thank you. 

I will download the tip sheet and again

THANK YOU!

Dawn

[bigmac]

Denis thank you for putting the link on for Glass Campus it's a really informative site.