Marring on burn cuts

Can anyone offer any advice on either cleaning these or preventing them all together? These pics are uncovered burns but it happens even on covered ones. This is on 1/8 pine from home Depot. Cutting at full power on non-pro at 120 speed.


I don’t know the basic settings so much but that seems pretty slow for cutting 1/8” pine. You’re getting the flashback because you’re blowing through the material and it’s hitting the honeycomb with a lot of power left.

Sounds like some experimentation is in order to nail your settings down right.

I’m going to bump this over to the #beyond-the-manual section since it’s non-Proofgrade material, and support won’t be able to help you with those settings.


Personally, I’d say it’s med-Proofgrade poplar. Change it to manual to see what the settings are and use that as a baseline.

1 Like

I’ve done some experimenting with this. I’ve gone from 150 speed 3 passes to 120 speed 1 pass. Otherwise it wouldn’t cut through. I’ll try it again tomorrow around 125 speed and see how it goes.

Is that just solid pine? Not plywood?

The default settings for poplar and other medium hardwoods looks to be about 210/Full for the pro. The pro has more power but you shouldn’t have to drop the speed that much, I wouldn’t think.

On the Pro, that’s 46 inches a minute. Your setting of 120 is about 11.5 inches per minute.

Are you inputting the material height into the unknown box? Autofocus should still kick in there though and focus ok.

Is the material warped?

Are you in need of a cleaning?

If you have cleaned, are you sure the lens was put back in the right way?

If you have cleaned before, did you cut this material before you had cleaned - or only after?


No matter the setting, do yourself a favor and test on small simple designs like a square. Go through a half dozen tests to find the best setting.


There’s no pine available in the GF store, nor in the Inventables materials store, which has much more selection. There might be a good reason for that.

Suggest trying a small piece of the “problem” design on a piece of poplar or other hardwood.

My guess is the speed is too slow. The longer it stays on the wood the more it burns. Also some pine has resin or tar and that can affect the burn issue too. Testing is the key, since different wood reacts to the laser differently. You use full power for cutting, so try increasing the speed to 145 or 150 for a start to see if it cuts all the way through with less burnt edges.

1 Like

Another important thing is the filler and glue in the plywood. I have found some plywood from Home Depot and Lowe’s just will not cut! I wasted a lot of wood in the beginning due to poor plywood. The hobby plywood at craft stores usually works. My local lumber company had a special Baltic birch ply that is for boats and airplane that is wonderful. You might also order online from Laser Jumstart and the wood Gallery. Other laser vendors sell wood and acrylic too. Note that Laser Jump start is not really ply it is a wood product, but it is cheaper and cuts wonderfully. They will send you free samples to try too.

1 Like

He’s not cutting plywood.

You’re right on the resins, that’s why I pointed out that pine is uncommon material for laser work. I can’t imagine how gummed up the optics would get from the vapor that creates!


FWIW - I found this stuff on Amazon:

Set it for medium proofgrade maple ply and it cuts / scores / engraves perfectly.

Now that doesn’t answer your question, but I have been cutting some 1/4" Poplar lately for a few wood working projects and haven’t had this problem. I ran a series of tests at different power, and I think 2 passes at 75% power gave me the best result (I don’t remember speed, but it was low-ish, probably 175). I didn’t want excessive burn on the edges or blow back like you’ve seen.

1 Like

The short version is that you’re overpowering your cuts, either because you ran it too slowly for the power you were using or ran too much laser power for the speed you were using, depending on your perspective (power-first or speed-first thinking).

As @nancielaing said, the general idea for most materials is you want to cut hard and fast, so my suggestion is:

  • upload a test file with several different colored small squares (1/4" x 1/4" should be plenty)
  • set your power cut parameters to be full power on all, and then set speeds to cover a range. I would start at 200, then the next square 220, 240, 260, 280 and so on up to about 300 or so.
  • Run it and see where you get clean cuts with minimal flashback.
    • If none cut cleanly, then slow it down. Do another run covering 100-200.
    • If they all cut cleanly, speed it up. do another run covering speeds 300-400.

You should be able to get dialed in pretty quickly, if you want to further refine it, you can get it down to increments of 10 speed units, which should get you close enough. Keep in mind, you want to get consistent cuts, so being too precise with speed rating will actually hurt you a bit. Materials are analog, and you get variations. If you dial it in to full power/213 speed today, you may find your next piece of material needed closer to 200 and get disappointed.

In general a tiny bit of flashback is inevitable if you’re using settings that will consistently get through the material. You can mitigate that by using masking, a sacrificial material under your board, or both. Just be sure to compensate for additional height that the sacrificial material might be adding.

Certain types of cuts and materials are more prone to flashback damage. You can search the forum for “flashback” and find lots of discussion on the matter.


OP already said 150/3 passes wasn’t cutting through, which indicates to me that something is up.

Any idea of what kind of pine it is? Pine hardness can vary significantly from about that of Wenge to about that of basswood.

1 Like

True, but no mention of power in that 150/3. Given that 120/full got through with major overburn, I suspect 150/3x wasn’t full power. I personally question if it’s 1/8" pine at all, because I’ve never seen home depot carry any solid wood that thin.

This is the tricky part with support via forum, too many omitted details to really make an ironclad analysis… so I posted my general procedure that works for most everything.

1 Like

Agreed - thinnest hardwood I’ve found is 1/4"… I go to Rockler for anything thinner.

Thanks all. I mentioned the power on there as full power. I was typing all that from my phone so it was a little problematic typing.

I think it is prob pine pressed board or something cheap like that. These are pre-cut boards near the saw in home depot. I think it is the resins causing that. I think I’m going to try the wood that @mrinken linked. I never would have thought of Amazon for wood. Go figure.

pressed board is VERY different from simple pine. as you mention, the resins change everything.

1 Like

If you can find a local hardwood supplier that carries 1/8" ply, it’s almost always the cheapest option. Depends on where you live, etc, but I find that my prices are 50% + less then most online vendors.

Agree - but what I like about the stuff on Amazon is consistency. I haven’t had a piece that’s bad at all.

i’ve ordered two boxes from woodpecker of the 12x12x1/8. first box: fantastic. second box: warped all to hell. not like a little bit because, you know, wood can warp. i mean big warp.

interiors have been fine so far, but trying to flatten those things out enough to use has been a nightmare.

and the stuff i got at the local wood supplier was at least as good as the first good box, but less expensive (even after having it cut down) and was cut to 12x20.