Laser Etching Stainless Steel With Mustard

[Brain] wanted to mark some scissors with his Ortur laser engraver. The problem? The laser won’t cut into the hard metal of the scissors. His solution? Smear the scissors with mustard. No kidding. We’ve heard of this before, and apparently, you can use vinegar, as well, but since the mustard is a paste it is easier to apply. You can see the result in the video, below.

In case you think you don’t need to watch because we’ve already told you the trick, you should know that [Brian] also goes into a lot of detail about preparing single line fonts to get a good result, among a few other tips like improvements to his air assist setup. On a laser cutter, the air assist blows away charred material leaving a clear field of view between the laser and the remaining uncut material. Using a proper air assist can really expand the capabilities of these inexpensive laser cutters — something we recently saw upgraded with a 3D-printed air assist nozzle.

You can buy a commercial marking solution called CerMark Black, but you probably already have mustard. If you are super cheap, you can probably pick up a packet next time you buy a burger somewhere. After all, you don’t need much. Although the video talks about the Ortur, this technique would work with any engraver. We’ve also heard you can do something similar with plaster and alcohol.

24 thoughts on “Laser Etching Stainless Steel With Mustard

  1. The cheap alternative to CerMark is spray lubricant containing molybdenum, available at any automotive parts store. Also, as a spray it’s easy to apply.

    I’ve also had luck with Kapton tape – the beam burns the tape into the metal and leave a nice line. Use very low speed and high power – I was using something like 10mm/s at 80 watts of power with the Kapton.

    I suspect that a lot of easily-available materials can be used for marking metal.

    1. I used the CRC dry moly lube you are reffing to quote a bit in the beginning of my laser adventures, but my recommendation to all is to stick to cermark LMM6000 for steels for consistency and durability. Cermark also has a new one called Ultra that I like to use on glass and ceramics because you can buy a small spray bottle for 10-15$. It says you can use it on steels but I tried it on a stainless cup and it failed horribly…the glasses that I did look great though

  2. Can anyone explain what is going on? Is this based purely on the optical properties of mustard (which is not reflecting the laser beam like the stainless would)? Or is there some heat-assisted chemical etching going on as well?

    1. I’ve a book on it somewhere. In essence yes. Bit of both. Very much depends on temperature, pulse length and chemistry.

      For low power lasers and mustard, it’s likely staining of the surface with carbon and baking on a very thin layer of burnt stuff.

    1. It’s a bit of a quibble, but while the Hershey fonts may be good for engraving, they were designed for use on CRTs back in the dark ages (late 60s) when computing curves and splines would have been too computationally intensive. From there they no doubt moved to pen plotters which were equally limited in capability.

  3. Around 1980, I worked with a laser machining system that used a 100 watt YAG laser. We wanted to cut white ceramic sheets and they were very resistant to being laser cut. The engineer in charge discovered that they would cut just fine if they were coated in milk of magnesia, which is available cheaply at any pharmacy.

  4. I keep telling people those green laser safety glasses the chinese include with blue or violet lasers are worthless and not even the correct color to block the light from those laser. At the very least get a orange or red safety glasses, Brian! I also have a DaVinci Pro 1.0 and watched some of your videos so please get some better laser safety glasses so you can keep your eyesight and make more videos!!!!

  5. Gave this a quick try on a kitchen knife this morning. Didn’t have any luck on my first run. Think it’s because my air assist was blowing most of the mustard out of place, and with burning nasty nasty mustard I really didn’t want to turn off air assist. That said will try a few runs turning down the air pressure later. Laser cutters are being used to make pcbs by burning off etch resist strategically. I’m wondering if something like mustard is enough to etch copper deep enough to make channels after a polish when done.

  6. I just tested this on a circular saw blade I had sitting in my basement with a 50W CO2 laser, and it also works that way! The marks seem to be quite resistant to scrubbing off, so it is successfully chemically etching the metal. Very neat. I need to experiment with this to figure out how to make it work in a consistent and clean manner, I have a lot of variation based on mustard thickness (that’s a freaking weird sentence out of context)

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