Shelf Primer Flaking Off Shelf as it Dries

[ejgiebel]

I recently did a screen melt using a piece of stainless steel screen I had used before (so no weird metals involved, 304 stainless). It was a 20 inch circular piece, so I wasn't able to cut a piece of clear thin and place it on shelf paper inside the stainless steel ring I used for a dam, so I coated the shelf with 12 coats of Bullseye Shelf Primer. Screen melt came out fine, with some amount of expected primer sticking to the back of the glass, but no sticking of the glass piece to the kiln shelf. I scraped the shelf clean as normal, and gently sanded off the areas where the primer was especially stuck to the shelf.

However, in subsequent preparations of this shelf, there is a spot (about a 3 inch circle) where the primer goes on fine, that is, it soaks in and doesn't bubble on the surface like an overfired bisque mold, but as the shelf dries, it flakes up like paint peeling off an old house. One time I dried it in my garage workshop, the second time it was in the Arizona sun, but this is the first time I've seen this happen, and it's happened the both times I primed this shelf since the screen melt.

Any idea how to fix this, or is this something time will heal? Fortunately it's towards the outside edge of the 21 inch round shelf, but I need to put the original piece back in the kiln, and I can't have the primer peeling off before I start.

Thanks,

Ed