Friday, October 18, 2013

Thinning the Pot Melt (Whoopsy!)

Well I got mixed results in my attempt to make the thin the original melt piece from 15 mm to 6mm.  It definitely spread out and got thinner but ended up 9mm thick and this is where the problem occurred.
I got quite a bit of devitrification on the piece (which can be cleaned up easily) but the big problem was the thermal shock during the cool down.

I think there were two contributing factors.  First I had set my kiln self directly on the floor of the kiln to accommodate the height of the pot melt but I had forgotten to put the shelf back on the furniture so I suspect the bottom of the piece heated unevenly.  There’s more cracking on top than there is on the bottom.


The second problem was the firing schedule. 

100 900 45
150 1100 30
200 1250 30
FULL 1475 30
FULL 960 45
100 800 0
200 700 0
400 250 0

I set up a ramp schedule to what I thought would work for a thick piece (15mm)  The mistake I made was my assumption that the piece I’d be pulling out would be 6mm thick.  In other words the cooling schedule was to fast for the thickness of glass.   On my next fuse attempt I’m thinking I can actually increase the ramp up speed since the glass is thinner going in but this time I’ll play it safe and go with a slower cool down even though this next fusing might thin the glass even more.  Here’s what I’m thinking I might do for the schedule.

250 900 45
350 1100 30
150 1250 30
FULL 1475 20
FULL 960 60
50 800 0
100 700 0
200 250 0
Blogger Labels: Thermal Shock,Devitrification,Pot Melt,Melt,kiln,shelf,furniture,glass

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