Ok, technically I just engraved away the paint, but these came out pretty nicely. I used the iPhone 7 material settings then adjusted the material height. Took 6 minutes at 700/100/270. Using vectors is great because crisp lines show up even at a “lower” dpi.
Here are the flasks in the picture
I had to remove the crumb tray and then prop these up on 2 sheets of scrap 1/8" material to get it to where the laser would be able to hit it well. There are 2 great tutorials in this site about how to measure and do things without the crumb tray.
The engraving left behind a sticky residue, but that was quickly and easily removed with isopropyl alcohol (91%, not the 50%)
it all depends on how much material you put under the flasks. However, the Glowforge now has an auto-height detection feature so you no longer have to put in material thickness.
These 2 videos should help:
“Work without the crumb tray”