Playing with fusing and slumping again, but having real trouble getting nice edges, even when the glass looks straight before the fuse!!!!
Any tips please!!!
(http://i1088.photobucket.com/albums/i325/purple_cobwebs/dichro2-3cmx4.jpg) (http://s1088.photobucket.com/user/purple_cobwebs/media/dichro2-3cmx4.jpg.html)
(http://i1088.photobucket.com/albums/i325/purple_cobwebs/dichro13cmx5cm.jpg) (http://s1088.photobucket.com/user/purple_cobwebs/media/dichro13cmx5cm.jpg.html)
(http://i1088.photobucket.com/albums/i325/purple_cobwebs/fusedandslumped10cmx10cm.jpg) (http://s1088.photobucket.com/user/purple_cobwebs/media/fusedandslumped10cmx10cm.jpg.html)
How thick is your glass going in? Is it one or two layers all over, or just in some parts.
Glass likes to be 6mm thick, so if it's less, when it is soft and at fusing temperatures, the surface tension will pull the glass inwards to try and make it thicker. If it's thicker than 6mm, it tends to 'blob' outwards.
Fully agree with Zeldazog but it looks also as if it may have been a bit over fired, perhaps soaked for too long?
Aha, yes the dish is made up of two layers, each of 2 pieces of glass. The worst edge is where the top and bottom edges did not meet perfectly, so I guess the thinner piece pulled in a bit.
On the pendants I started with a black rectangle of glass, and then fused a smaller rectangle of dichro on top. So again, I have a thicker layer in the middle and a thinner one on the edges. I suppose I need to add clear around the dichro.
Thanks for the help. ;D
Or grind the edges to straighten after firing and then fire polish.
I would put a layer of clear either under or over the dichro, depending on what effect you're after. And try to watch what's happening in the kiln (if you've got a window) when it gets around the highest temp. If it starts looking runny, either stop it heating up any more, or stop the soak, and (either way) open the door about an inch for a minute or so, until the temp goes down a bit, then shut it and let it cool and anneal on the programme.
HTH.
Nick
Yes I think the other posters are right about it being a result of the "six mm rule". Also, it looks as though you might have devitrification on the edges of the black on your dish (unless it's a reflection). I get that if I grind the glass at all before firing and don't give it a really good clean :(