Some quick notes for ways of marking metals with a CO2 laser.
Commercial
Cermark LMM-6000, supplied from Trotec (engraving-supplies.ca)
They also have LMM-14 Black. It maybe an older product? Not so popular? - https://sawmillcreek.org/showthread.php?241326-Thermark-LMM14-vs-LMM6000
There is also a Cermark marking tape (Black Marking Tape 1" x 50 ft roll) but I remember reading people weren’t happy with it (would need to re-check that.)
Molybdenum Based Alternatives
- The key compound is molybdenum disulphide (or chromium disulphide- more on this one below)
- Cermark (Enduramark?) also adds a very fine glass powder that also gets fused on (with clay slip to transfer heat) so it bonds to the metal
- Molybdenum dry lube has been used as a cheaper alternative:
- Video showing results: https://www.youtube.com/watch?v=za160j7cJP4
- Quickly scanned some other people getting mixed results. Seems thicker, more solid layer is needed (need more molybdenum - Thermark is probably higher % than the lubes)
- Note: he also holds up a container of MoS2 powder from Eisen-Golden labs (https://youtu.be/za160j7cJP4?t=110)
- The spray most people use appears to be CRC 03084 (https://www.amazon.ca/CRC-03084-Lubricant-Aerosol-Spray/dp/B0013J62P4/) - ~$50 for 12oz, ie ~1/3 price of Cermark
- Note: a lot of bicycle (chain) labs are Mo based… could be an easier to get hold of option for small tests
- Video showing results: https://www.youtube.com/watch?v=za160j7cJP4
- Why not use MoS2 directly?
- Leads to a nice sounding recipe, and easier to clean as the carrier is not an oil: https://community.glowforge.com/t/cermark-alternative/5641
- Scroll down for some comparative images between Thermark and an Mo experiment
- https://www.amazon.ca/Molybdenum-Disulfide-Powder-Space-Saver-Bottle/dp/B015VBW9UG - $50/14gms. No idea how far this goes…
- Leads to a nice sounding recipe, and easier to clean as the carrier is not an oil: https://community.glowforge.com/t/cermark-alternative/5641
Stainless Steel Only - Calcium/Chromium Substitution
Plaster of Paris for Stainless steel (only?)
People report that this effectively etches where the laser hits. One theory: "I believe this is working due to the chromium content of the stainless steel. Stainless has a passivation layer that is thin and completely transparent; Chromium oxide. When combined with calcium sulfate (plaster) along with the heat from the laser and potential water from the surrounding air, you end up with calcium oxide and chromium sulfate. Chromium sulfate creates the mark and the calcium oxide washes off. Again this is my basic premise and understanding of what’s occurring here. “ (http://frankieflood.blogspot.com/2014/12/laser-engraving-stainless-steel-w.html)
Some links:
- https://sawmillcreek.org/showthread.php?215131-Stainless-steel-by-the-Plaster-of-Paris-method
- https://hackaday.com/2014/12/25/laser-etch-stainless-with-only-plaster-alcohol/
Dijon Mustard (Stainless Steel only?)
Cerkote
Super hard paint/spray on ceramic that can be laser engraved- https://www.cerakote.com/project-gallery?htids=Laser%20Engrave
Electrical Etching
Mask + teaspoon of salt… can use the laser to make the mask (eg tapes (non PVC vinyl!), engrave off spray paint…)