WarmGlass.com

650 C should do it, but it wouldn't hurt to go to 800 C.

You can polish with just a cork belt. No need to use cerium oxide, but cork does like more water than other belts.

If there's a bulge in the bottom then you'll need to flatten first.

It's hard to tell exactly what happened from the photo, but it looks like either you had a plugged airhole at the bottom of the mold or else you fired too high, which caused the piece to slide down the edge and create the bubble. Either way, it's possible to flatten the piece again, but it may be di...

Eric Bloom wrote:I think I found the answer ... right here on this website. I'll try adjusting my schedule.

https://warmglass.com/what-caused-this-huge-bubble/

Yep. I was just about the send you that link. Slow down, reduce top temperature.

Bullseye recommends cleaning with a vacuum with a HEPA filter and suggests that a respirator is only needed if you don't have a filter.

http://www.bullseyeglass.com/images/sto ... 1-2021.pdf

Large pieces can warp if not annealed properly. in addition, the stress can build up and cause the piece to crack. This can happen with both tack fused and full fused pieces. With this kind of piece, you can't just go into your anneal hold as you would with a smaller piece. Instead, you need to hold...

Here's how Skutt does it: https://skutt.com/skutt-resources/repai ... e-of-kiln/

If you google it, there are lots of other tutorials

A pair of regular nitrile or latex gloves should work fine. Gardening gloves are too thick and the gloves made for kitchen workers stop knife cuts but not glass ones.

It looks like you're firing a bit too hot. Try reducing the top temperature 10 degrees or so.

Is this the controller manual you have: https://019361d.netsolhost.com/catalog/ ... manual.pdf

Red Lion is here: https://www.redlion.net/ With luck they should be able to help.

Doug Zawodny wrote:All my firings for the last 8 years have been on thinfire. Never on a treated shelf. I have used a lot of turquoise, but always on thinfire. Ill retreat the shelves and see what happens. Thanks.

Thinfire wouldn't stop any contamination from getting through.

I don't see how it's the thinfire, but that's easy to test. Just do a firing on a kiln washed shelf.

Also, try the other side of your shelf.

Doug Zawodny wrote:I don't even know what silver stain is much less use it. Any other guesses?

It's the residue from using silver foil in the kiln. Ever used any?

Looks like silver stain. Have you used silver in the kiln recently?

The key word is "inexpensive." As far as I know, the ones that work on textured glass are anything but inexpensive. CR Laurence carries a brand (Woods Powr-Grip Textured Surfaces), but they're around $100 or more each. A slightly less expensive (and less powerful) option is the RUBI Suctio...

I heat at 100 on the way up, never more than 200. Also, pause 10 minutes at 500 to allow the heat to even out a bit before you get to the range where thermal shock is more likely. You can fire in a kiln with side elements if you can turn the top ones off. I routinely drop 3 to 4 layer pieces 4 1/2&q...

Looks like thermal shock from being too close to top elements. That kind of slit is characteristic of that situation. I usually see it in slumps.

Brad, full schedule for the piece or slump? The site won’t accept my iphone or ipad photos. I could send you one if your address accepts my photos. Schedule for the slump, isn't that where the problem happened? Photo is probably too big, but you can email it to me and I'll resize and post for you. ...

Photo? Complete firing schedule?