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.”
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Perfect. Thank you.
Slate looks wonderful when laser etched: http://cdn.notonthehighstreet.com/system/product_images/images/001/414/167/original_laser-engraved-slate-plaque.jpg
But I’m unsure as to its longevity. I’m betting a quick sealant or wax would prevent any real weathering, though.
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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.
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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: https://www.youtube.com/watch?v=lhfKHoeiEho
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@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 
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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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Great ideas and input. Thank you, all
I agree.
You would be able to cut a very intricate mask and take it to a memorial maker and have them blast it. Granite is essentially forever. I’m not sure of the material they use for masking, but before you laser it, do a bit of research on the material safety to see what the combustion by-products are so you don’t kill the neighbor’s dog… 
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