Stuck Mold

[Jane C ♫]

Hi Norton. Exact same firing cycle but with just ONE Minute hold at the top and everything else exactly the same.

If you're going to slump over ceramics and line with fibre paper then you need to use the 3mm stuff. Thinfire (or similar) doesn't give enough wiggle room.

[Norton Caff]

So finally managed to get to fire up the kiln and did as was advised by Jane and held 677°C for one minute. I laughed when I opened the kiln next day. The glass was off the mould and in a sort of lumpy plate like form. So I shall put it back in on the mould with a circle of thicker paper which just slightly overlaps the mould. Not sure what paper I have, it might be 6 mm so I might have to get some thinner stuff. Also I thought the glass was sticking on the sides of the mould too. I shall have a go at lining the sides! A bit like a cake tin in reverse.
My query is though, is 677° C too high? I am really new to all this and am not confident with the temperatures.

[Flyingcheesetoastie]

It depends how much you want the glass to move but I'd suggest starting at 650c and eyeballing what it looks like when it hits that temperature.  You also have quite a slow ramp from 593c and because Spectrum is a relatively softer glass in comparison to float or bullseye then it will be starting to move before it reaches 650c so I would not think much of a soak at that temperature would be needed.  If I'm slumping float then I usually hold for around 10mins at 650 but I would have ramped from 500c FULL to 650c normally.

The only way to know is open the kiln.... either after it's cooled or when it's at top temperature and you can still do something about it!

[Pat from Canvey]

The only way to know is open the kiln.... either after it's cooled or when it's at top temperature and you can still do something about it!

But don't forget your kiln glasses if opening at top temperature.

[Jane C ♫]

Hurrah! So glad it unstuck for you!

[Norton Caff]

Just out of interest, having had a lot more experience since I started this query.
I put a circle of paper on the top of the mould when first slumping this item. This meant the glass slumped in direct contact with the mould and cooled tightly!
My next ones I used a square of fuse paper under the square of glass and on the mould. This held the glass off of the mould and gave a more wavy result. I certainly learn the hard way.