> I was experimenting with textures and iridescent glass using fiberglass mat.
> Now my fused glass is coming out with some sort of grunge on it. I have
> just finished running the kiln to 1550 for 30 minutes with the peep holes
> open. Do you think this is enough to purge the contamination out? I'm
> currently trying to get ready for a show and this is making me crazy. > > Thanks
> --
> Connie Ryman
Should work. If not you need a higher temp, longer time, or both. I would have hit around 1800 for a while to make sure. Sounds like the mat might have had some additives.
Run a quick firing with black glass and you should know.