1/8 Birch Plywood (not proof grade)

So I am experimenting with my new Glowforge. I don’t want to use the more expensive wood (yet) until I have this figured out. So I ran to the hardware store and picked up some regular (not Baltic) birch plywood to play with (.20"). I tried a rather large cut (18x10) at 182/full, 1 pass. It cut most of it right through but it was slightly shallow in some areas. I am thinking it’s probably inconsistent core. I tried again at 2 pass and it didn’t seem to make much difference. Shouldn’t the second pass have easily gotten through the last couple molecules easily enough in those areas? Just wondering what I should be expecting here.

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That is totally normal with regular (and BB) plywood. Depending on the number of plys, gaps, glue, filler material, knots, etc. this should be your expectation.

You’ll get lucky on some sheets, not so lucky on others. Search the forum and you’ll find lots of discussions on plywood, finding gaps, and so on.

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I recently tried some projects in similar material. I had success with 150/Full including some masking tape on my Pro.

Plywood can be tough for several reasons. As mentioned, some of the glues (and how they can be inconsistently applied) can impact the cut.

Voids are also really bad about killing a cut.

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As an aside, note that some BB ply has formaldehyde in it, which is irritating when vaporized. For some brands I’ve resorted to using a specialist formaldehyde vapor filter mask.

Also, you can see some voids/glue pockets through the wood by using a sufficiently powerful light source to shine through it. If you use thicker plies (say quarter inch) the flashlight won’t work so in that case I run a preliminary cut job that puts a grid of tiny holes every half inch across the piece. Take it out, flip it over, and you can see where the pinholes don’t penetrate, letting you map the interior of the plywood and then orient your “real” cutting job appropriately.

…uh, that pinholegrid trick only works if you don’t mind the appearance of the finished piece of course.

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Agreed. This is why that “cheaper” ply can in some cases be a false economy – PG was developed to give very good (if not 100% perfect) results out of the gate. Using the provided PG sampler pack to get used to settings and such is cheaper in the long run. YMMV, of course.

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I’ve been using something advertised as Birch plywood that is about 0.172" thick. 155/Full on my Pro clearly cuts through 99.9% of it. For the 0.1% I flip it over and use a razor blade utility knife to slice it. Where I have to do this the edge is usually just a teeny bit ragged. 200/Full cuts through about 98% of it. So what I am effectively doing is overpowering the cuts and it shows in crispier edges. I’m okay with it because I’m making some larger stuff and around-the-shop boxes with it where a little bit of ragged edge here and there is acceptable. For smaller presentation items I’ll use proofgrade or something else.

Also, it does not take a finish that well.

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I cannot find anything less than .20 thick locally. Did you buy yours locally or did you order it?

I buy mine at Menards, which is local to me. They actually have a pretty wide selection of 3/16-1/4 plywoods. The stuff I buy is labeled as both 3/16 and 1/4, depending on the label you read, and measures .172, but that varies as well. Not exactly precision material.

Rockler carries 1/8" hardwood boards, I’m not sure if they carry that thin of a plywood.

True 1/8” Baltic birch runs at about 0.12”. It cuts way better than 1/8 “birch” which tends to sit at about .13 in my limited experience.

It’s possible that I got a bad batch of Baltic, 0.01” does seem like it might be natural variance but it was just not the same finish and definitely cuts much less consistently.

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If you want to order online a lot of people seem to order off of Amazon. Some people are very happy with their suppliers, others complain of warped boards.

If you want colored 1/8" plywood, I’ve only ordered once from The Wood Gallery, but it was quality product and less expensive than proofgrade.

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My go-to is 1/8" (.125 ish") Baltic birch. There’s a great warehouse locally where I can get it quite inexpensively in 60" x 60" sheets… which is the standard for imported Baltic birch. Domestic stuff at big box stores is 4’x8’ and frequently lower quality. The 1/8" bb I use gets pretty good results at proofgrade maple ply settings, and I’m happy with that.

I don’t have good consistent cuts with 1/4" and there isn’t a setting that has resulted well for me on a Basic glowforge. When I need 1/4" it is cheaper and less effort for me to cut two 1/8" and glue them together with clamps and wood glue.

The locally sourced stuff is not as amazing as proofgrade; but with a local supplier and a table saw I am comfortable with the margin of error at the cost I am paying. It’s significantly less costly than proofgrade for me.

If I didn’t have that source, I cannot say what my regular source would be; but I am certain that I would prototype more in cardboard than I do, and I am certain that my friends and family rate would be higher. I would do less volume.

Good luck with finding your go-to and getting the results you want.

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Mind sharing? I’m sure there are other glowforgers in the SLC area that would like to know.

I use 1/8 inch bb plywood pretty exclusively… even though I have a lot of other materials that just sit nicely organized on shelves. What can I say, I was dropped as a kid.

I have a basic and use 195/full and set the glowforge to .13, even though the wood is usually under .125. I don’t remember why, but there was a reason for it at some point. 200/full is actually a better setting for me if the boards are perfect, but I tend to err on the side of expecting-there-to-be-not-perfect-parts. I do still sometimes have problems when there’s a… plug thing on the back of the board, but that happens infrequently.

For engraves I use 600/59-800/79 (because clicking the 60 never seems to actually select 60. Is that just me?), but then never use straight black in the design to avoid going too deep. Because I like to work as complicatedly as possible, I guess. But now I have too many files designed that way to bother figuring it out.

I would say I have maybe 15% of things not cut out perfectly and need to be… encouraged. 2 seconds of sanding sorts out the splinterly edge so I’m not too concerned about it.

I order all my baltic birch from the interwebs. Actually, I pretty much order all of my everything from the interwebs. Because amazon. Except glue. I buy that from Home Depot like a fully functioning, well adjusted adult.

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The 60x60 is real Baltic Birch. It’s a defined product with manufacturing tolerances and standards. If it doesn’t meet the standard it’s not supposed to be sold as BB.

The stuff in big box stores is Birch plywood which is whatever the manufacturer wants it to be. There is no controlling standard. It does not always have laser friendly glues, can have whatever fillers (I’ve even seen Bondo!) They want and can be different from lot to lot from the same manufacturer.

There are some producers of 4’x8’ Baltic Birch but they’re primarily Russian and you’re not gonna see it at the big box stores.

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Absolutely!
MacBeath Hardwood.
300 West and about 1500ish South in SLC. West side of the road.
When you go, take 10 minutes to snoop around the exotics. It’s pretty cool.

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I use BB for most things. Just went to a local place and had them cut it to 20" to fit in the car. What I get tends to measure about 0.110, which is even under 3mm, but I design with it at 3.

About 180 for most cuts, 200 for the smallest ones.

Assume full power? Pro or basic?

Full power on a basic. I should really check 100% and see what that requires.

I have found that my Home Depot has 4’x8’ sheets of 3 ply 3mm plywood for $11! I don’t know what kind of wood it is, but it has a very smooth finish, seems softer than the birch I have been using, and it cuts like a dream at 200/full. It seems to have the same small amount of voids/plugs as the fancy birch I had been using. I feel like I won the lottery!

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