I love the Glass Coasters at http://www.glasscoasterstore.com but the red & purple are tempered which makes me think even with dish soap they may not stand up to thermal fracturing.
Has anyone attempted any engraving with tempered or is it a lost cause?
I believe most of the strength in tempered glass is surface tension. Although a friend in commercial glass told me you can sandblast both sides of tempered and crumble it in your hands.
I would be carefulā¦it can shatter very easily.
http://www.glassetchingsecrets.com/blog/tempered-glass-be-etched/
I am confused that post specifically says you CAN etch not carveā¦ not to mention he is using sandblasting not a laserā¦
Hummm found this:
This is on an Epilog which is 65 watt -
Ok so I placed an order - I will let the community know of my success or failureā¦ in about two weeks 
Put a tray under the glass just in case, keep you from having to clean it out of the crumb tray, just in case.
@tennessee_reid how did your tempered glass lasering go? Iām about to try some phone screen protectors. Any settings that you can share?
Been working on an animated show for the last 23 days straight and have not had anytime to try - got my coasters and attempting a run today!
Trying both dish soap and glass cleaner āmasksā
Power 100%
Speed 850
LPI 340
Lets compare notes!
Donāt 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 BBās 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.
Soā¦ 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.
What does this do?
Sprayed on āPerfect Glassā glass cleaner as a āmaskā and let air dry. Never even bothered with dish soap as the GC worked like a charm.
Super happy with the results - no issues other than alignment on the colored tiles. I plan to cut an alignment jig before producing any quantity.
Well thatās some stunning results! What gave you the idea to use the Perfect Glass cleaner?
(Might have to get some of that.) 
When searching the forum and reading and reading and reading posts - now I canāt remember where I read it and I neglected to bookmark, someone suggested trying glass cleaner in place of dish soap for a more uniform āmaskā. 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 VoilĆ !
Well, i just ordered some. That looks like one of the most uniform results Iāve seen on glass. 
Revised settings I now find 270 LPI to be superior -
Yeah, my bottle came in (donāt know that Iāll need 32 ounces, but that was cheaper than the smaller bottle)ā¦now i just need to find some glass to etch.
(Thatās a joke - Iāve got a weird thing about washing out and saving bottles - I could probably supply every owner of a Glowforge with half a dozen to practice on.) 
To clarify, spraying the glass with this cleaner and letting it dry leaves a āmaskā that will keep the laser from bouncing back and ruining the laser? Iād sure love to quick scraping tape off my designs!! Have you tested this extensively? TIA!
