Still working on a couple of issues engraving glass with 10watt Diode laser. Using black tempera paint. I ran a material test and this seems to be case on them all…
When the job is finished, there is an amber colored coating in outside of the engraving (back side.)
If I work at it, I can scrape of the coating and get a decently clear engraving.
Pictures aren’t that great, but maybe you can see what I mean.
Appreciate any ideas…
What is the surface underneath your glass? I get something like that when I engrave the backside of mirrors and I don’t have a clean surface under it. Especially if it is a wood surface. I believe it is off gassing from the wood. Sap and moisture being driven out.
Try your test again with a white, shiny paper under it. I bet it will come out clean. Printer paper may be enough, but the more gloss the better result.
I’m laying my tempera coated glass…coated side down… on my not-so-super-clean honeycomb pad. Focus on the top of the honeycomb.
I’ll be trying your suggestion soon.
Thanks.
Try coated side up. I always do it that way.
Black paint for white finish and white paint for a darker finish.
Yes, coated side up. The paint has to escape as it is get ablated by the laser. Much better to let if dissipate into your air extractor than to get trapped under and then stick to your piece of glass.
i lay my glass on black sheet and focus from top of glass,
my standard glass settings are way faster, being so slow heat may be playing apart in it also ,
i run around 7500mm/m at 65% power with 20 w laser on 5mm glass, as you have 10 w do a test say from 1000mm/m to say 5000mm/m see how that goes
IMHO, it looks like some type of fiberglass/epoxy.
If it’s epoxy or a fiberglass of some kind it could very well be toxic debris. If I try to cut F4 type pcb with my fiber, it has a difficult time getting through the fiberglass and looks very similar.
Are you sure you’re safe lasing this ?
Well, it’s black tempera paint from Hobby Lobby…I don’t have the brand with me right now…it’s in my workshop.
Will try that…
I tried this with the glass lying on a shiney white piece of ceramic tile. Not much difference.
Ok then. Be sure that your painted surface is on the top, so the fumes and smoke are not trapped against the glass when they get lasered.
