This was done with Thermark on Titanuim alloy knives with a 35 wt laser. I’ve also marked stainless steel, brass and regular steel alloys.
you also use Thermark on the brass?
Yes, here are the settings for the laser…
http://www.thermark.com/TM_Downloads/Settings/LMM14_Laser_Settings.pdf
This is what I am going to be most interested in. I already have an order for 50 Cal BMG shell casings with text engraved (marked) on them for custom pens. I am going to be doing a rather large lot and will be looking into the different marking sprays as well as dry molly lube as that might be a suitable replacement to cermark and thermark seeing as those two are rather pricey!
Just to clarify, having operated several different industrial production grade CO2 CNC lasers (Mitsubishi & Bystronic) I can speak on which metals are the hardest to cut/engrave with a CO2 laser.
Worst to easiest:
Copper
Brass
These materials were rarely cut in the shop, their reflective pretty much prevent them from being cut with a laser. We tried many things, from various focus depths, assist gas pressures, modifying the surface by fogging/misting specialized surface treatments, even mild sanding. The best results were achieved with combining an 400grit orbital sand AND application of a surface treatment mist. Even then the second shift operator cause machine damage when the beam reflected inside the laser and distorted some of the cutting chamber “windows”.
Aluminum
Stainless
Steel
These materials were and are cut all the time, but not with 40 watts More like 4000 watts, and 100->280psi assist gas.
not to mention an issue i’ve read about with copper is how reflective it is when it melts, so your laser needs special shutters; even when you manage to cut it, as you indicate, you’re always going to have the reflectivity issues…
Don’t forget that copper can also be smelted with arsenic