Flashes on the corners

[Martman]

Hi

I fused some bullseye glass for the first time at 804 C but all pieces have flashes on all 4 corners little spikes of glass it's as if the kiln wash held on to the glass.  

Is it the kiln wash or the temperature, I had a piece of float glass 6mm total thickens in as well but that did not fuse just tacked, the bullseye pieces all fused (except for the flashes)

Any one have any idea

After applying the kiln wash how can I ensure that the shelf is smooth ie no ridges from brush strokes.

Mart

[flame n fuse]

Hi Mart, Have you looked at Bullseye technote 4? which has explanations of what happens at different temperatures and some fusing schedules.
http://www.bullseyeglass.com/images/stories/bullseye/PDF/TechNotes/technotes_04.pdf
was it a single sheet or double? If it was single - this is expected to happen at this temp.
If it was double, is it possible that your kiln is hotter than you think?

Hope this helps

[Martman]

Thanks flame n fuse

I have just read that, it says that float glass fuses at 38  C higer than Bullseye if the kiln was hotter I would have thought that the float glass would have fused!

Can you post images on here?

Mart

[Zeldazog]

Can you post images on here?

Instructions on how to post images here:

http://www.frit-happens.co.uk/forum/index.php?topic=23036.0

If your kiln is firing say 15 or 20 degrees hot, that's still 20-25 degrees below a full fuse on float glass - so you'd still get a tack fuse on the float, whilst over firing the bullseye...

As a guide, I have to fire one of my kilns at 795 to get a good full fuse on Bullseye, so that's a good ten degrees lower than recommended.  All kilns are different.

And as Flame and Fuse suggests, if it was only single thickness glass (glass likes to be 6mm thick) you're likely to get needling at the edges, shelf paper or kiln wash, as it tries to 'pull in'.

As for getting the shelf smooth, getting rid of brush strokes, when the wash is completely dry, simply rub over it with something like kitchen roll, on the flat palm of your hand, usually a circular motion, but nice and gently.  You can get a really smooth finish.

[flame n fuse]

I also full fuse Bullseye at lower temps than the Tech notes suggest - I get a better finish at the lower temp, and find I get devit on some colours (opaque blues especially), if I do it at the recommended temperature.