@ca_worth ; Moving this thread to Beyond the Manual so that settings can be discussed (that is the only place we can discuss non proofgrade settings).
@aprilsmith0113, The first part of glass settings I use is: Always buy a spare of whatever glass item you are engraving so that you can test out the settings and tailor them to the specific glass item.
There is so much variation in glass settings because there is a lot of variation in manufacturing glass and glass is really sensitive to it. For these particular shot glass I have had batches where no masking, 800 speed, 70 power, 225 LPI work perfectly. I have also had times where those settings caused to chipping of the glass. It just depends on the batch I end up with.
Masking and dish soap both are great options if you are having issues with flaking. Whenever I mask I always do two passes. The first pass burns the masking into the glass and so the second one burns away the residue.
You can try my settings of no masking, 800 speed, 70 power, 225 LPI but I would just try it on one and then feel the glass after and make sure there is no flaking.