Don’t know much about tempered glass, but worked (drilled) with some safety glass lamp covers before, with mixed results. The covers were 30 foot up on the ceiling, and two had fallen out. The owner wanted them gone before someone got beaned. They were about 20 inches round and I figured they could be re-purposed. I wanted to make macrame shelves with them.
First one I let it get too hot and the entire thing burst into 1,000,000 tiny glass BB’s that became tribbles. (whenever I thought I found the last of them, another group would be uncovered).
Learning from that, I kept a constant cold wash on the bit while drilling holes in the remainder.
So… If a hot bit will burst 1/4 inch safety glass, I would say there is no low limit that would work with a laser.
When searching the forum and reading and reading and reading posts - now I can’t remember where I read it and I neglected to bookmark, someone suggested trying glass cleaner in place of dish soap for a more uniform ‘mask’. I happen to have PerfectGlass in the studio (my unauthorized GF lid cleaner) it is as clean a cleaner you can buy with no additives. Eh Voilà !
To clarify, spraying the glass with this cleaner and letting it dry leaves a “mask” that will keep the laser from bouncing back and ruining the laser? I’d sure love to quick scraping tape off my designs!! Have you tested this extensively? TIA!