Question about laser etching on thin gauge sheet metal

Has anyone every painted over a laser etch (this would likely be processed on a high-wattage fiber laser) that's on thin (around 18-20 ga) steel sheetmetal? We're making a matte black magnetic board for a CAD camera system and need to locate targets accurately. So it would be etched, painted (likely spray can to keep it thin) and then need to place peel & stick targets inside an etched circle.

Thanks,
The Dude

The Dude said:

Has anyone every painted over a laser etch (this would likely be processed on a high-wattage fiber laser) that's on thin (around 18-20 ga) steel sheetmetal? We're making a matte black magnetic board for a CAD camera system and need to locate targets accurately. So it would be etched, painted (likely spray can to keep it thin) and then need to place peel & stick targets inside an etched circle.

Thanks,
The Dude

Click to expand...

I would suggest testing the paint to make sure it does not fill in the etch. Probably needs to be at least .001" to .002" deep to avoid being filled by paint.. I would imagine the best way is to make a test strip with rows of etched lines in increasing depth from smallest to largest and then paint the part and see which one is visible enough without being too deep.

Lot of parameters to play with. For sure you can go deep enough and for sure you will see the lines under paint. Power level, height, gas pressure all come into play, focus too. Low height, high power, high pressure will give you deep lines and a surface finish good for stair treads, non slip.
Line density also comes into play as a dense series of lines will warp your sheet.
Fiber laser will melt the surface and gas will help with an indentation. Try 3-5 mm height.
If you have a lot of little lines in a dense area then not possible with oxygen. At some point what worked with low density line spacing will get too hot and oxy will burn holes through. I've experienced that on 10g.

When you say laser etched do you mean laser engraved? Laser engraving is very shallow but you could either engrave after paint, or even more pro, engrave on black oxide.

Thanks all, I am having it made with an "engravement" (yes, "etch" is not the correct word, thanks). It's a one-timer and have some other options so it's worth a shot. So nice that laser cutting is cheap, two large sheets and two test sheets to play with for about $100.

The Dude

When we did this in the past, laser engraving needed to be about .003" deep to keep paint from filling it. Also make sure your line isn't so thin that the paint could possibly bridge it. Thin paint is key. Unfortunately paint durability suffered with the thinner paint.

Oops: sorry to revive. Hope it helps someone.

dc2012 said:

When we did this in the past, laser engraving needed to be about .003" deep to keep paint from filling it. Also make sure your line isn't so thin that the paint could possibly bridge it. Thin paint is key. Unfortunately paint durability suffered with the thinner paint.

Oops: sorry to revive. Hope it helps someone.

Click to expand...

No worries on bringing back an old post, your info you added is good.