Normally after I put kiln wash on a shelf I put it in the oven and let it bake 200 degrees for an hour and then bump it up to 500 for 15 minutes or so to get all the moisture out. On this occasion I forgot to put a timer on and it ended up baking at 200 degrees for a couple of hours. I figured this was enough, let the shelf cool down again and then used it a few hours later to tack fuse this project.
The failure to bake it at 500 degrees turned out to be a mega fail.
I figured I could fix it by drilling a hole in the bubble and then taking the piece to slumping temperature. I flipped it upside down and filled the depression with water. I cut the hole using a 1/8 inch carbide tipped glass bit and a Dremel moto tool.
Of course one hole wasn’t enough for me. I was being a bit paranoid and tried drilling a second one because I was worried that the hole would seal up as the glass settled and I’d still be left with a bubble. The first hold drilled clean. The second one not so much.
But this doesn’t necessarily bother me either since I had planned on putting a layer of colored frit on top and then doing a contour fuse. I’ll just fill the hole in with frit. Unfortunately the small cracks pictured here weren’t content on staying “small” and grew to split the piece in half. I’m still pretty confident that I can salvage it and fuse it back together. The lesson here is you want to make darn sure you’ve got all the moisture removed from your shelf before firing something like this.
Dang! This smarts though…