View Full Version : trouble Vector cutting Baltic Birch

Shaddy Dedmore
06-21-2004, 3:08 AM
I bought some 1/8" Baltic Birch ply at a craft store. On my epilog 35w 24tt, I used 100% power and 12% speed. I had to run it 2 times, and there were still spots that didn't get all the way through... is this normal? I would have thought that it'd cut better than that. It says in the manual that it may have trouble with some plywoods, so to use the better wood, which is what I thought I got.

When I do a second engraving pass, should I refocus a little lower than the first pass? I've just been using autofocus so far.

I have a bunch of scroll saw patterns that I want to do, but now I'm not so sure I can even do it. What kinds of wood would be best for this. (I have some acrylic ordered, but it won't look as good as wood for some of the patterns I want to do)

Thanks for any tips or tricks.

Doug McIntyre
06-21-2004, 6:10 AM
You're correct in saying that cutting ply can be troublesome - it states much the same in the ULS handbook as well. I'm told it is due to the inconsistent 'hardness' of the woods with the grains crossing over on each layer and the varying amount of adhesive spread.

I usually set the cutting speed at a very low level and overkill on the power to make sure it cuts all the way through. If flaming or burning becomes a problem, masking with signmaker's tape or water spraying just before the cut often helps. Water spraying is good for small jobs but it dries out pretty quickly on the larger ones.

Maybe doesn't apply to your particular job but 'wetting down' with a spread of newspaper on the workpiece is often recommended especially for glass engraving. I keep a box of these pre-wetted baby wipes beside my machine - just spread over the work instead of messy newspaper when you suspect burning or flaming will be a problem.

Keith Outten
06-21-2004, 6:14 AM

You could drop the speed a bit more to something like 7% but watch your first cut carefullly in case the ply catches fire. I think when the manual mentions "Better Woods" they mean lumber not plywood. Plane or resaw your wood down to about 1/4" thickness and it will vector cut fine in one pass. Of course there are wood species that won't cut, like purpleheart.

I have had good luck cutting maple, walnut, poplar, alder and cherry.

Steve Clarkson
01-28-2009, 8:51 AM
So I bought a piece of 3/4" baltic birch from Michaels to see if I could cut it with my 45 watt.....well I guess that answer is no!

It's about 90% through, but no matter how many passes I make, it won't go any further. I tried changing the focus, but that didn't seem to work either.

Should I make another 23 passes and hope to eventually get through.....or chuck the piece in the garbage and consider it a learning experience.....or does someone have a magic secret for me?

Kenneth Hertzog
01-28-2009, 8:56 AM
just reverse the drawing and turn the wood over :D


Steve Clarkson
01-28-2009, 9:08 AM
I was thinking about doing that.....but it's kind of a complicated design, and I wasn't sure that I would be able to hit the cuts EXACTLY right.....but that's definitely my last option before tossing it in the can.

Oh.....and I was cutting at 600 dpi 8s/100p/500F.

Patrick Licata
01-28-2009, 10:45 AM
I have run into this problem before and we came to the conclusion that it is the glue that is used in the layers. If the glue used is an exterior grade glue (or course you have no way of telling) then not even dynamite will go through it. (ok maybe it will, but you get the point.) I have a 35 watt and did multiple passes on some birch without success. I sent a piece of the wood to a fellow creeker to try with a 60+ watt and they could not get through it either. There are a couple of Creekers who sell the wood here and I have good success with them.

Larry Bratton
01-28-2009, 11:01 AM
Biggest problem with cutting plywood is to get it absolutely flat. I can cut 1/4" birch but I actually end up masking it on the back and nailing it down to a piece of mdf to keep it flat. The mask on the back keeps the residue off in the absence of a cutting grid.

Rob Bosworth
01-28-2009, 11:37 AM
Try lowering the frequency of the laser. If the range for the frequency or rate for your machine is 0 to 5000, try setting the rate at 600 to 700 and see if that does not improve your cut through.

Also, focus your beam about 1/3 of the way down through your material.

IF you have air assist, turn it on and let it blast.

Good luck

Robert Ray
01-28-2009, 12:42 PM
Yes. I agree. Lower PPI. I mostly cut thin Birch plywood, and found that the 200 pulses per inch (Laserpro Drivers) setting gives the most cutting power and cleanest cuts.

What i did to determine the best settings was to cut the same small part with different PPI settings from 50 to 500 PPI, and compare them for find the most complete cut without burning. I found I had to lower the power as I lowered the PPI, which made the cuts almost smoke free, and the edges of the plywood come out char free, and even a little sticky from resins.

-Robert Ray

Michael Hunter
01-28-2009, 2:04 PM
As Patrick says below, the type of glue between the plies has a huge effect. Also, whether it is 3- or 5-ply (3- is MUCH easier to cut).
When buying, you need to specify "Interior" ply, rather than the normal WBP waterproof glue stuff - then you will have a chance of cutting it well.

I can cut 9mm (just under 3/8") 5-ply on my 60W machine, though it does give sooty edges. 6mm 3-ply cuts cleanly with good edges.
I also bought a sheet of 3mm 5-ply which was supposed to be interior grade, but I can't cut it without getting soot and mess everywhere!

Todd Schwartz
01-28-2009, 5:02 PM
Shaddy, join the club, I have pile of "good" baltic plywood bought at a local distributor that does not vector cut.

Issues with plywood are a couple and both have been hit here. First you need the good baltic birch that has no voids. The voids will fill with glue and you will never cut through it.

Also, you need the interior glue. I have found that I can vector cut baltic birch, but not finnish birch - been told that the finish birch has a silica in the glue, regardless I have not had much luck with finnish birch.

A trick I have learned is that if you look at the end grain and see a dark brown or black glue line between the plys, chances are it will not vector cut. If you see either no glue line a very light line you odds are good it will cut.

The solution - look for a creeker who sells 1/8 ply that vector cuts well - as mentioned, there a couple here that do a great job.

For sizes they don't carry, I have also had good luck with Sloans Woodshop. I am sure there are other good ones out there as well.

Good luck,


Michael Kowalczyk
01-28-2009, 6:03 PM
The plywood that comes from the hobby shops can also be marine grade or airplane grade. As mentioned above there is a big difference between interior and exterior glues. We use 3mm B/BB interior Baltic Birch plywood exclusively and about the only issue I have is the rare occasion of a football on the back and only cutting 96 % of the way through. So I get out the exacto knife and then lightly sand or file the edge, if it is salvageable and does not detract from the edge quality.

I would think that maybe you should just use 3/8" ply, cut them out and then glue them together. Just thinking out loud but it may also depend on how intricate the project is that you are cutting.

Thanks and ...

Steve Clarkson
01-28-2009, 6:04 PM
I was at 500......but I'll drop it down to 200 on pass number 14 and see if that does any better. Thanks!

Marc Myer
01-28-2009, 7:46 PM
I do a lot of 1/4" ply cutting as well. On my 35w Mini, it usually works well at 7 speed, 100 power, 400-500 frequency. Some plywoods have a mahogany layer inside or on the back. That stuff is nasty, stay away from it. At best, the mahogany cuts inconsistently. I have found that a local big lumber supplier for contractors will also have a good supply of plywoods for the craftsmen who make their own cabinets, etc. You can also get some pretty sweet deals on remnants and big sheets that have broken edges, etc. They will tell you what the ply is made of, what's good to use, and will even have some cool unusual woods or samples to try out.

And of course, Gerorge Perzel's woods are great.

Dave West
01-28-2009, 9:23 PM
I cut alot of 1/8 and 1/4 ply on my ancient Epilog profile 25 watt. I get all my stock from my local hobby shop. Look for 'Lite Ply' on the sticker. I think it's actually Poplar and not Birch, but it cuts like butter. Never had a problem. 1/8 is cut @ 100 Power and 50 speed, 1/4 @ 100 power and 30 speed. The airplane grade is noticably heavier and a bit harder to cut.