CO2 lasers are great for wood, acrylic, and leather, but they have a well-known blind spot when it comes to bare metal. The beam simply reflects off the surface, leaving nothing behind. For small shops and hobbyists who don’t have the budget for a fiber laser, a marking spray is a common workaround. OMTech’s 8-ounce black marking spray is one of the more visible options in this niche, so I spent some time testing it on a few different metals to see how it actually performs.
The basic idea is straightforward: you coat the metal surface with the spray, let it dry, then run your CO2 laser over it. The laser burns the coating, and the heat bonds a dark mark to the metal underneath. The process feels a bit like a science experiment the first time you try it, but it’s not complicated. You do need to be careful with the application. The spray goes on fairly thick, and a light, even coat works better than a heavy one. I found that two thin passes, waiting a minute or two between them, gave a more consistent result than one thick layer. The drying time is short—usually under five minutes in a normal room—which is convenient.
In terms of actual output, the marks are genuinely dark and reasonably durable. On stainless steel and aluminum, the contrast was strong, and the detail from a 40-watt CO2 laser was sharp enough for serial numbers and simple logos. The mark feels like part of the surface rather than a painted-on layer, and it resisted light scratching with a fingernail. For a product that costs around $25 per can, that’s a decent outcome. It’s not as permanent as a fiber laser engraving, but for many practical uses—tool labels, nameplates, small parts—it holds up well.
One thing to keep in mind is that the spray has a distinct chemical smell. It’s not overwhelming, but you should have ventilation in your workspace. Also, the residue after lasering is a bit messy. The unburned coating doesn’t just disappear; it leaves a fine black powder that needs to be wiped off with a damp cloth or alcohol. That’s not a dealbreaker, but it adds a cleanup step that some people might not expect.
Where this product really shines is in its simplicity. You don’t need to adjust your laser’s settings dramatically. I used similar power and speed settings to what I’d use for laserable plastic, and the results were good. The spray is also forgiving if you’re slightly off on focus. It’s a practical tool for someone who already owns a CO2 laser and wants to expand its capabilities without buying new equipment.
However, there are limitations. The mark is not as durable as a fiber laser engraving, especially on softer metals like brass or copper. On those surfaces, the coating tended to flake off in thin layers if I pushed the power too high. You also need to be aware that the spray is not a one-step solution. It’s a consumable, so you’ll need to keep buying it, and the cost adds up if you’re doing a lot of parts. For high-volume production, a fiber laser or a marking system with a different technology would be more efficient in the long run.
Compared to alternatives like ceramark or dry moly lubricant—which some people use for similar purposes—OMTech’s spray is easier to find and more consistent in application. Ceramark tends to require a higher temperature to bond, which can be a problem for lower-power lasers. The OMTech spray works well with standard CO2 wattages, which makes it more accessible for the average user. That said, if you’re looking for a permanent, high-contrast mark on bare metal, you might be better off with a fiber laser or a chemical etching kit. Those are more expensive upfront but offer better longevity.
Who is this for? It’s ideal for hobbyists, small business owners, and anyone who already has a CO2 laser and wants to take on small metal-marking jobs without a major investment. It’s also useful for prototyping, where you need a temporary mark to test a design before committing to a permanent process. On the flip side, it’s not the best choice for industrial-scale production, nor for metals that will face heavy abrasion or extreme heat. If your work demands marks that survive years of rough handling, this spray will likely disappoint.
Overall, the OMTech Laser Marking Spray is a functional, no-frills product that does what it claims. It’s not a miracle solution, and it has a few quirks like the smell and the powder residue, but for the price and the ease of use, it fills a real gap for CO2 laser owners. Just don’t expect it to replace a dedicated metal-marking system. For occasional jobs and small-batch work, it’s a handy addition to the workshop.