You are right
Well, you have guessed much of the job. I’m bending over a mould of metal.The marks are at side of the mould, like they occured from the solution that I put on the mould to avoid sticking metal to glass. I have made curved glass at much lower temperature, but here is the tricky situation, because I’m also trying to fuse the paint on the glass – paint is something like ink and needs higher temperature. So I have to find the balance between needed temperature for the ink and the lowest possible for curving the glass – something like that. I was wondering if these spots appear if I’m firing too rapidly – but the steps are – 1 – 1.30 h to reach 300 C, 1.20 h to reach 550C, 1 hour to reach 675 C.
Thanks for the quick answer. I will also check your blog for additional info.