CO2 Laser Etching on Metal Using Dry Moly Lube

Moly lube this is an industrial dry lubricant that’s used in applications where you have metal parts sliding against each other but you don’t want to use grease. Moly is short for molybdenum, the element, and this type of lubricant is in the same type of family as things like Teflon. Teflon is dry and allows objects to not stick to each other or reduce friction.

So what does this have to do with laser engraving? Well the ingredients in this can are very similar to Cermark, which if you don’t know, is a laser marking compound that you apply to metal and then you can make a dark permanent etch on a CO2 laser cutter. CO2 laser cutters cannot normally etch on metal – you need a fiber laser for that. But with a CO2 laser and a can of Cermark – or molybdenum lube – you can etch on metal and get a dark permanent mark.

So why would you use this instead of Cermark? Cermark is a great product but a can about this size costs $80 or so and this can cost between $15 and $20 depending on where you get it. From my experience Cermark is better at the job, but if you don’t need it to be a perfectly dark etch this this is perfectly adequate.

Case in point, the project I’m working on today. My husband and I cook a lot and we use kitchen scales and we occasionally run into the situation where we forgot to tare the scale before placing the bowl on it and we want to know what the weight is minus the bowl so we need to know how much the bowl weighs. Now I could commit to memory that this bowl weighs 65 grams but that’s asking a lot and it’d be much easier if I could just pick it up quick and look or peek on the bottom and see that – oh 65 grams. I’m not going to use a can of $80 etching compound on something as silly as this, but a can of dry moly lube? Perfect! Let me show you the process!

From my experience moly lube isn’t quite as harsh and potent as spray paint so you could probably get away spraying this indoors but I like to use the portable spray booth that is my truck bed whenever I can. Other than not being overly harsh in the smell department, it sprays just like spray paint does. The moly itself is mixed with the solvent and propellant that evaporates off the surface very soon after it sprayed, leaving behind a thin layer of the molybdenum we’re interested in. This footage is real time so you can see how fast the solvent evaporates and thus is ready to etch.

This was actually the first time I worked with moly lube on my Thunder Laser machine so I needed to figure out what settings work best. When we got new silverware as a wedding present I saved all of our old mismatched silverware to use for tests like this so I dialed in my settings on the stainless steel butter knife since my bowls are stainless steel as well. In fact I used the same can of dry moly lube to etch our cake cutting set with our names and wedding date six years ago – and that’s a perfectly acceptable result right? Like, if I use Cermark this would be darker but I was happy with it! I used a Brillo pad to scuff and try to remove it and it stayed – it had staying power!

But of course, I did the cake cutting set on the old makerspace laser that I used before getting my own so back on my test knife I did five different power settings at 400 millimeters per second. I ended up landing on 40% power as the one I thought looked best after washing the excess moly lube off. I’ll show you how to do that later in the video. I did a quick little design in illustrator to mock up what I want to etch on the bottom of these bowls including a template layer I could etch on the scrap board for aligning the bowl rims. From there I placed my bowl down and let the autofocus on my Thunder Nova 35 do its thing.

Then I fired my job, which compared to some materials you etch and cut on the laser is a bit of a non-event: there’s no visible smoke like with wood there’s no obnoxious smell like with acrylic and there’s no flashes of light like with glass. In fact once the job is done it may be a little hard to see where the etch is depending on your lighting, but on my way into the house to wash it off you could make it out in the direct sun.

Washing it off. A dry lubricant wouldn’t be very useful in industrial applications if it just wanted to flake off super easily from the surface you sprayed it on so it does have some sticking power. If you rub with something moderately abrasive like a paper towel for long enough while running it under water it will eventually give in and come off but I’ve discovered that pumice hand cleaner – i.e. the same stuff you use to get paint off your hands works great at this task as the tiny little abrasive pumice particles very gently scrape it off the surface. You don’t need to apply a ton of force, just gently massage it in with your fingers or paper towel and then rinse away and voila nice dark etch.

So because we have half a dozen of the same style bowl, I had a few more to do and was easily able to batch process them all the same way. So if you’re etching on metal with a CO2 laser and you don’t need the etching to be super dark I say save the Cermark for those important jobs and just use moly lube for everything else. Now the intent of this video was just to show that you can use moly lube to etch on metal but in the future I want to do a one-to-one comparison of Cermark to moly lube on a variety of surfaces so be sure to subscribe so you don’t miss that video. But in the meantime grab yourself a can of dry moly Lube to use for low level or silly jobs like this. I’ll have a link below to the stuff I use.

I’ll see you in the next one! Cheers!