I just use the proofgrade settings, 1/4" walnut I use thick walnut setting & 5/32" walnut I use medium walnut setting & so on.
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The only 1/4" non PG material I’ve had really good luck with was a red oak I got from a lumber yard (not Lowe’s or HD). I found that I get good results using the Thick Maple Plywood setting. I have been successful in cutting some 1/4" maple ply I got from the lumber yard, but had to slow the cutting down just a couple degrees to get it to cut through, although it left quite a bit of charring, so I only use it on stuff I don’t care too much about such as boxes that I plan to paint.
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Check out #6:
The bottom line is that no one can tell you exact settings for your material, you’re going to have to test to be sure.
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I find 1/4" (6mm) mdf cuts great, but the 1/4" mdf plywood with hardwood veneer is very hit and miss and is also unpredictable based on the grain of the wood on the underside. Cutting with multiple passes causes it to look too burnt.
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So I got some Columbia Forest 1/4" double sided Walnut (0.20" measured )from HD and it cuts like butter at the thick walnut plywood setting! Just ordered some red oak and mahogany! This will work out great for my purposes. Thanks for everyone’s help
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Good to know! I love their Maple product, and won’t even try to cut any other 1/4" ply anymore. I tested lots of manufacturers before trying the Columbia Purebond. And for those interested, I recently tried to find 4x8’ sheets of the same quality at a plywood seller (Rugby). Turns out that Home Depot prices are pretty great for a B1 grade ply. What Rugby had available was B4, which I wouldn’t even touch.
Plywood grading is A, B, C, D, for the front, and 1, 2, 3, or 4 for the back. Anything less than a 1 for the back is going to make consistent lasering not great, since it allows larger knots and whatnot. Home Depot must be buying in very large lots to offer it at the price that they do, especially once you take into account the drudgery work of moving with a trailer, then cutting down to size that a large sheet of plywood would need.
I’ve been meaning to try the other flavors from Columbia Purebond that HD offers, thanks for adding your experience about how well they cut!
Oh, and by the way, since my laser is older, I slow the speed of the PG Thick Maple setting down by 10 so that it is 140/Full.
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The pre-cut Glowforge-sized packs never touch Home Depot’s hands. They’re shipped directly from the manufacturer to your house (or to your store for pickup).
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that’s a fair point, but i think what’s still happening is the HD factor bumps up the volume to allow columbia to keep that price low compared to some of the other vendors.
IIRC, columbia forest originally only did 12x24, which is a standard size. but enough people asked them (and one of their sales folks was in some of the FB groups) and they added the GF sized sheets.
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I just wish they had 1/8" too.
They have 5/32" and their maple ply is probably my most used material for the past couple of years.
Never, ever had a problem with it, It’s not masked, but I rarely need masking. GF-sized sheets at a very reasonable price. Much better than Baltic Birch from Rockler.
The only “issue” is the sheets are not flat, so they have to be pinned down. I don’t consider that a problem, as even Proofgrade materials need to be for the most part as well.
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(I just checked a couple of scraps and new sheets… the 5/32" is .135-.1355" That’s way closer to 1/8" than 5/32" - which would be .156" or so.)
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Good to know, thanks. I just printed out a conversion chart because I am so horrible at math, and see how close to 1/8" the 5/32" is. And if your test scraps are only .135, that’s really good!
I’ve done 1/4" hardwood walnut before with one pass. I can do some oak, but not all. 1/4" plywood is hit and miss, depending on the glue and the core.
The Glowforge is best with 1/8". Pro does better with thicker though.
Best tip I got for cutting 1/4" is setting focus height at .125". I’m able to get through maple and walnut hardwood measuring .27-.28" with one pass with my pro at 120 speed Full power.
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you can probably go faster than that. i’ve been cutting a lot of 1/4" walnut hardwood the past few months at 135/full (on a basic). and i’m focused at the actual height (1/4"). zero issues, clean cuts.
Setting the focus height to .125" when cutting 1/4" material means you’re trying to cut with a fatty of an out of focus laser beam, spreading out the heat over a larger area, which makes it less effective at cutting.
120 is very slow for cutting 1/4" material on a Pro, you have to go that slow because you’re trying to cut with the equivalent of a dull blade. Keep the focus set to auto.
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Good to know, anything to save time is helpful.
Setting the focus height seemed to create straighter edges for me on thicker material than auto, maybe it’s in my head but there’s a thread from a year or more ago regarding it.
you’re probably going to see some pretty diminishing returns on that at 1/4". and that’s probably why you had to cut at 120 instead of faster, because your beam was defocused at the surface. and it may lead to much larger kerfs.
when you’re cutting something very deep and doing multiple passes, it may have more value to change the focus on subsequent passes.
Here was my test on 3/8" maple, focusing at different heights:
Here’s another by someone else, on acrylic:
Both have pics, if you click on them. 
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