Yes, oil tanned (like that) is a hot mess in a laser. It might be possible to brute force through it but I wouldn’t count on it.
Conversely, you can get through really thick veg tan - thick enough to make a belt - faster than 1/8" acrylic.
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Alas, the Internet has a rather different interpretation of the term “hot mess” - hence my request for someone to simply snap a photo with their smartphone of what the laser cuts of different types of leather looks like, both successes and failures.
OMG! I had to look!!! OMG!!!
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for some reason this is the first thing that pops into my head when I see or hear that term.
If the glowforge team ever attempted it again, I would love to see them recreate this photo. If I worked there I would make it happen hahaha
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For the record, “hot mess” is from @dan , not me. But thank you to @spike and @takitus for demonstrating how ambiguous that term is.
I’m beginning to wonder if (not unlike the movie reference) most laser cutting fails are trashed without any trail of evidence, which is a shame. If you search for “3D printing fail”, you get all kinds of funny but informative results that I found very helpful in ramping my expertise in that realm.
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The only place I’ve heard “hot mess” is in Arrested Development. https://s-media-cache-ak0.pinimg.com/736x/10/e0/1d/10e01d7e8063ed267ee40b896de84880.jpg
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Is that from “The Thing” ?
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yeah! I was wondering if anyone would get it 
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I’m anxious for someone to prove me wrong, but here is my theory:
Any laser cutting issues involving leather are immediately destroyed with no photographic documentation - only successfully laser-cut leather is photographed. This is considerably different from the 3D printing hobbyist market, where lavish sharing of both successes and failures has greatly enhanced the art and industry.
The purpose here, is to figure out how to overcome the “cooked mess” issues associated with chrome-tanned leather. The easy answer is “don’t do it”, but we’re sitting on over a K$ of chrome-tanned inventory that was purchased because it has a unique set of attributes that veg-tanned leather can’t match. I was hoping to elevate the GF beyond just a way to consume GF-supplied veg-tanned leather…
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While I can’t recommend using materials whose emitted properties are not known, I have definitely both made and seen made some really cool stuff from chrome tanned leather.
Oil tan might be possible, but after a little fussing (and discovering how well veg tanned work) I gave up.
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@dan, in your experimentations with oil-tanned leathers, did you get any sense of the physics of what was going on? Oil has pretty good heat dissipation characteristics, as peeps that do metal cutting/drilling know. The more time the laser spends on one spot, trying to cut all the way through, the more time it conducts heat laterally, hence “cooking” the surrounding leather.
Perhaps running multiple fast passes over the same cut would ablate just a bit of the leather on each pass, allowing the material to cool between passes. Running ten passes in a GF would still be preferable to cutting by hand.
Oil is actually pretty bad at conducting heat in the static sense that conduction is usually used. It works well in metal cutting because 1. it is a great way to reduce friction, and 2. it absorbs some heat and leaves the area with it. Water based cutting liquids are a hell of a lot better at getting rid of heat overall.
In leather where the oil is sort of bound in place and can’t move I don’t think it will conduct much. It might boil out of the cut area though and that might absorb some of the laser energy? (and generally make a mess)
@jkopel, agreed - I suppose the absorption effect as you described in #2 is what I should have said. In general I would think the “wetter” the leather is (whether from water, oil, wax, etc.,) the more resistant it will be to cutting, and the more porous (e.g. veg-tan) the leather the easier it will be to cut.
Very good point regarding the energy required to vaporize the oil - that could be where a lot of the laser energy goes. And it could be the oil doesn’t fully ablate, but turns into something else undesirable.
Still wondering if cutting using several passes could be beneficial to getting through at least some of the more challenging leather types.
My guess is that it is in fact the oil ablation that’s eating up energy and making a mess. The solution, limited though it is, is multiple passes - it will get you there but the edge may not look nice when you’re done.
One trick I’ve used (painstakingly) is to put blue tape over the cut line, do a light cut, retape, recut, and so on - ablating just a small amount of tape plus material each time. That tends to produce nicer edges, albeit very slowly, on persnickety leathers.
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@dan, thanks for the observations. If multiple passes makes the difference between working or not, I’m in. The cutting speed of the system is what it is - that was never a factor in choosing to order the GF. For example, I run my FDM printer well below its rated speed, because I forget all about how long it took when I remove a cleanly printed part off the bed.
I like the principle behind the blue tape suggestion (and I’m a huge fan of blue tape!), but does it have to be tape? I was thinking a sheet of heavy paper or card stock could serve to pin down thinner leathers, and the laser should be able to blow right through the sacrificial paper.
Is the honeycomb base in the print chamber magnetic? That would be awesome for enabling magnets to hold down the material.
danStaffOct '15
Unfortunately ferrous metal grates are a lot more expensive than aluminum, even though they last a lot longer.
Fortunately we love you all and sprang for them anyway! Barring any manufacturing challenges (the comolded plastic/metal crumb tray is one of the most complex parts. after the case) magnets will work and the thing will be tough as nails. Literally.
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Woo-Hoo!
And @Xabbess is, as usual, right on the mark.
The problem with non-adhesive is even a tiny bit of airgap (like if you use tape and don’t stick it all the way down) means the paper is surrounded by insulative air, full of rich oxygen, which defeats the purpose - it burns away and increases rather than reduces the burnination.
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the makings of a great title or quote actually. Now I want something promotional along the lines of:
Glow-Nation
Burn-Nation
Glow Life
Forge Life
My other car is a Glowforge
Great Sticker material
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Awaken your inner child again, Glowforge!