I ordered a bunch of square spice bottles to laser. The actual width of these is 2.04" so I ended up engraving at 0.04" out of focus…which ended up being pretty bad. The engrave is really lumpy, which seems like I need either more speed or less power. Near the end of the engrave the glass fractured from the heat stress.
Speed 300
Power FULL
LPI: 340
Focal depth 0.500
Passes 1
Some of the guys have had good success coating the glass with dish soap or glass cleaner or covering it with a damp paper towel. (Dissipates the heat so the glass doesn’t fracture.)
You might want to try a search for “Engraving Glass” in this category to find their tips. (I’ve not tried it yet, but there are a lot of tips for it in here.)
Did you use any “coating”? Usually if I notice a “unsatisfactory” engrave on a piece, I leave it in the 
, copy the design multiple times on the object with different setting of various dgrees to use as my “test” . Then see what works best before putting another new piece in… you can even label the piece (sharpies) with the various settings as your “example” or “sample” piece (you may want that “lumpy engrave” as part of a project some day).
I think what you’ve done is GREAT.
In my testing, albeit very limited, I’ve found I didn’t need to go anywhere near that slowly. As a matter of fact, I’ve used 1000 with great results. Power, on the other hand made a huge difference. Full seem to me to be the only way to go, just as you’ve done.
