The Truth About Cutting Chrome Tan Leather With A Laser

In the past the chrome tanning process used to contain Hexavalent Chromium which was dangerous when cut with a laser. This is no longer the case as Hexavalent Chromium has been banned from the tanning process and has been replaced with trivalent chromium. Trivalent Chromium is completely safe when burned and does not cause any issues with health or to the laser.

This is only a quick summary, I will link the video where the professor of engineering from he university of SA gives a lot more detail.

Would love peoples thoughts and opinions.

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I really appreciate your post. I have many chrome tanned leather bags from a company called Portland Leather, and their bags are made in Mexico, and I am reaching out to them to ask if they use trivalent chromium. I’ve been badly wanting to engrave a bag, but I choose to err on the side of caution, so I have not done so because most of their bags are chrome tanned.

Thank you for sharing this information!

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I’ve been cutting/engraving chrome tanned since the beginning - with good ventilation that’s not blowing out into an area with people I haven’t had any issues :slight_smile:

Interesting though if I ever wanted to engrave something vintage!

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…I talked about it with you on here. I’ve only done it very occasionally though…and with short projects.

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Interesting…I thought polyurethane was safe to cut…?

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What does polyurethane have to do with this discussion? I am ignorant when it comes to chemicals and material properties, so maybe you could be more specific.

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In the posted video, he states that cutting polyurethane produces cyanide gas, which is toxic. Everything I’ve seen and read (even in this forum) says that PU is laser safe, but the guy in this video says it is not.

The info about the chrome tanned leather is great to know!

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Thanks. I obviously didn’t pay close attention to the video.

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There is some polyurethane that contains PVC - PVC produces hydrogen chloride which is why it’s always good to have the SDS or know exactly what it is you are cutting. Buying products that are already marked as laser safe means offloading that responsibility to someone else - which is totally valid,

Not sure what the video said before and after the polyurethane comment, but it might be germane to the question.

Also - all polyurethane is bad for the lungs, so be sure to have good ventilation that doesn’t dump straight into an area where people are!

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Thanks for that answer.

So, if something is labeled as 100% PU, can it still have PVC in it? That doesn’t seem right to me…:thinking:

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If that 100% label is from the manufacturer? I would presume I’m good.
If it’s from Amazon? Not a chance.

There is a burn test that looks for chlorine gas that you can do if you’ve got extra material…

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Actually, PVC (polyvinyl chloride) creates hydrogen chloride, a corrosive gas that will ruin the inside of the machine.

Polyurethanes in general do not contain chloride but they do produce carbon monoxide and hydrogen cyanide upon combustion.

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Doh! I fixed that in a later reply but forgot it in the original!

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Heh. I should have read further down…

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Nearly everything you laser will produce toxic byproducts. For more context read #4:

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Hmm… ?? I’m confused.

https://www.osha.gov/laws-regs/standardinterpretations/2009-06-29

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Hey it was banned in the UK not in the USA, however since then tanneries no longer use hexavalent chromium tan their products. However I would still buy from reputable tanneries that abide with the EU regulations and not from China if you plan on engraving/cutting chrome tan leather!

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I think that since there are many users in the US and other countries, it should be called out that the ban is in the UK so as not to mislead people reading the post.

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We may all be confused by the hideously complex way safety things are handled in the USA (because, when in doubt, we always pick the most absurdly complex and yet also useless mode of regulation); while OSHA does not ban hex chrome they do have a number of rules regarding it:

https://www.osha.gov/hexavalent-chromium/standards

…in my past life some of these were exceptionally irritating, as we constantly had to prove our welding processes didn’t involve hex chrome (1926 Subpart D, Subpart J, Subpart Z).

Kinda like how we had to prove our laydown yard didn’t produce “notable” levels of silicon dust when the trucks drove on it, because god forbid anyone have feldspar in their gravel mix. Even though the roads they drove on to reach the laydown yard were basically 100% feldspar gravel.

…and yet at the same time the rules kinda made sense because I got to watch a guy die horribly because he entered a Wheelabrator when he shouldn’t have, because the guarding wasn’t sufficiently impassible. It is impassible now, even though that also makes it a PITA to service.

When you see a kid die horribly, and I mean really horribly it tends to re-set your thoughts on safety regulations unless you’re a straight-up psychopath.

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So I had to do some googling, a bit morbid but I was curious.

Basically a giant metal surface prepping machine like a massive sandblaster but doesn’t use air. Yeah that wouldn’t be good.

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