Ideas, suggestions, and thoughts....please? Marking on Metals and Stone

I have a project in mind that can use some ideas, suggestions, and insights from any and all of you skilled and more laser-knowledgeable people.

Please bear with a little background. My dad passed over 30 years ago, but my mom, bless her heart, hung on until she was 103 and finally passed in Nov. 2014. My brothers and I interred their cremains in a plot in a small pioneer cemetery only this last July. Since that time, I will own the fantastic Glowforge and have realized that I would be honored to be able to use it to make a permanent marker for them.

We are not very fond of the ‘store bought’ markers available and would like to have something more organic, symbolizing their love of travel during their lifetime. Perhaps a chunk of basalt or some other type of rock, with a metal plaque either glued or riveted into the rock. I am aware of the limitations of the Glowforge…as well as my own limited knowledge, but here are some thoughts and questions I would like to throw out there for now;

• Which types of metals will show marking or ‘engraving’ better than others?
• Will the metal marking wear away eventually?
• What metals will wear better than another when exposed to weather?
• Anyone that can explain how Cermark works and/or point me to online information or education about it would be wonderful.
• I love slate. What kind of results could possibly be expected from engraving on a piece of slate, then fastening that onto the main rock face?
• Anyone who knows about various types of rock would be helpful. I know that it will have to do with what kind of rock is available to us in our area (Oregon)…and that obviously something like sandstone would not be a good choice….but I have little knowledge about that, in general.

Anything at all that anyone might be able to share with me will be most appreciated and helpful. And certainly any other ideas that are different than my own about what we might do will be more than welcome. Thank you, all.


Used Cermark a little. Has great permanence though I’ve also heard that for longterm UV exposure you might want to coat the finished product with a UV resistant coating. (edit: after thinking about it, might have been the brass plate that benefited from a UV coating and not the Cermark) Here is a link to Thermark which is a similar but not exact product that shows resistance to various exposures, chemicals, etc.

This is how Thermark and Cermark work.

As far as slate or other rock goes I would think exposure to the elements would fade any marking. The laser may slightly shatter the surface of rock/slate but it’s more of a bleaching effect than anything. Doubt it will hold up well. But that’s just my guess.


Thank you, Rick. That’s exactly the kind of info. I’m looking for.

Forgot to ask you…are Thermark and Cermark different in some ways? Or are those just two different brand names? And how would I choose which one to use?

There are differences. Too many to list here. Most are subtle use differences. Here’s a paste from one community forum.

“The simple answer is Cermark is ethanol base and Thermark is water based.
What this means is Cermark is more durable and dries faster you can spray several plates and then wrap them up and put them on the shelf to use whenever.
Thermark will scratch off very easy so pre spraying and storing is not a good option but it is non hazardous for shipping.
Cermark works well on most metals, Thermark seems to work better on softer metals Alum, Brass, Copper and it also sticks better to Chrome.”


Perfect. Thank you.

Slate looks wonderful when laser etched:

But I’m unsure as to its longevity. I’m betting a quick sealant or wax would prevent any real weathering, though.


If you follow the mini foundry link from this post you’ll see a video about a backyard foundry. My knowledge of foundry work and sand casting is limited to a great grandfather was a sand caster and foundries were very dangerous. But it would seem there may be a path to a metal plaque here using the glowforge to help make the mold. My only other thought is dan says the glowforge marks stone really well and you could then encase it in something that is impervious to the elements.


That is really beautiful. I would love using that, but even trying it using a sealant might be a little risky considering it’s for a very long term thing. Thank you.

Thank you for the link. I watched the video. I think that’s not a route I will try, but I’m still always interested in various methods for things. I’m thinking more along the lines of marking stone, too…but it would have to be something thin enough to fit into the Glowforge, then be able to attach it to a larger stone marker. That’s partially why I was curious about using slate. Appreciate your input.

Anodized Aluminum is pretty durable, and you can use the laser to bleach the anodization without removing it. You can also get the anodization in different colors. So, if you get a black anodization, the lasered image or text should show up white-ish.

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Great info. Thank you. I actually WAS considering anodized aluminum but was not aware of the details you mentioned. Would it show adverse affects being out in the weather day in and day out? I like the idea of black background.

This may have been discussed elsewhere, but I’m wondering if multiple passes would be of any benefit as far as durability goes? It certainly would be much easier on the GF than any other laser.

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Depends on which material you are talking about. With the anodized aluminum you are just etching the anodized coating. The Glowforge can’t etch aluminum at all. With the slate, I really don’t know if multiple passes would have an effect. Never tried it.

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Yes, I was thinking more in relation to slate or other stone materials.

Personally, I would probably go the sandblasted granite route rather than laser for this particular project. Using your newly developing vector design skills, make your image, and have it cut from sandblast resist by someone with a plotter, then sandblasted onto a slab of polished granite, as in this video:


@rpegg - I thought Thermark/Cermark were pretty much the same. They’re both made by the same company now (Ferro bought Thermark). I use LMM14 (Thermark) because it’s a bit easier to clean up as it’s water based vs LMM6000 (aka Cermark) which is solvent based (alcohol?). Have you noticed any real difference in the marking characteristics of the two?

I’ve seen that they have colors (Cermark has more colors) for glass/ceramic laser marking. Have you used any of those? If they weren’t so freakin expensive I’d get some of each to play with but it’s hard to justify the plunge without having seen some work or having a specific use case for it.

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Only used Cermark and only the black for stainless. There are a lot of posts on other forums that indicate a slight difference. Can’t provide first person experience. Sorry.

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Thanks. I’ve only used Thermark black and on non-stainless (Cermark is supposed to be a bit better at producing a dark image on stainless).

Just one more thing to add to the question pile at the Makerspace this week :smile:

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As long as the anodization is intact, there shouldn’t be an issue with having it outside. That being said, if there are any sharp corners, it it possible to chip the anodization. Worst case, you could get some white powder (aluminum oxide) on any unanodized section over time.

I should probably also mention that I don’t know how the lasered portion will react over time. My guess is since the anodization is just being bleached, it should be fine, but don’t quote me on that. I’ll see if I can find out more about it.

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