As the title implies, I would like to engrave the caliber of each upper on the ejection port cover. I have a 10W diode laser (it started out as an OLM2 Pro but I’m now running a B-N-B 3), and a 60W CO2. I use the diode laser to engrave anodized tumblers, and it does a pretty good job. The coating appears to black oxide (similar to the coating on most black screws. I’m wondering if anyone has tried this and had any success. I don’t have any extras to experiment on, and I think the settings I use on tumblers would be a bit much. My thoughts were to either do a direct engrave (just remove the oxide), or mask them and give them a spritz of white paint. I’d appreciate any suggestions anyone has to offer.
Anodized steel, if that is what it is, may be different than aluminum. Can you test on the back side? Steel can also be annealed, which the laser may not change.
Had a thought… If steel, the anodize is to prevent rust.
I’d planned on engraving both sides of the cover, so that the caliber was visible whether the cover was open or closed (but mostly when closed). The blank cover is steel of some sort (heavy but not magnetic, which is unfortunate because I was going to use magnets to hold it in place on the jig). As I mentioned, the surface finish is matte, thin and very much like the finish on all the black metric hardware I get from Amazon. If no one pipes up with a suggesstion for a starting point I may have to scrounge through my junk pile and see if I can find something close to experiment on.
No, fortunate because it is likely stainless and that is the only metal a diode can mark (anneal). There are also laser marking sprays for metals.
You locked in on white? You might try this…
Brilliance Red (Copper Tone) Stainless Steel Laser Spray Can - 12oz Aerosol
I was only vaguely aware of these marking sprays, and I thought they only came in black. The downside is that for the cost of one can (yes, I realize that I can use it for other projects) I can buy the four covers I would need. I do want to thank you for the idea, and I’ve added it to my wishlist on Amazon.
Thank you for the suggestion, I found a single sheet (more than enough for me) for a 1$ on AliExpress. I ordered one and we’ll give it a try when it gets here. I’ll report back with the results. The listing says for CO2 and fiber lasers, so I’ll fire up my 60W OMTECH when it shows up next week.
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I bought the $22 2oz tiny can of Cermark because I believed $60+ for anything in a spray can was outrageous. But a 1/2-second burst is more than enough.
Can you give it a tiny Diode test and let us know if that works too?
I used the black with a diode on ceramics with optimum results.
Will do. I feel a little more comfortable with my diode laser for this sort of thing. I save the big stuff (cutting/charcuterie boards and the like) for the CO2.
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Thanks for the feedback.
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Interesting that you chose 6.5 Grendel for your example… that is precisely what I want to do with my 10W laser. Hope you have success and keep us informed on your progress.
Make your 10W laser into a 6.5mm Grendel?
Sorry, couldn’t resist… 
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Mil-spec dust covers are 7075-T6 aluminum and type III hard anodized.
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