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Angus Hines
01-09-2008, 10:18 AM
Had a great time with Eric Fuller yesterday showing him the laser and trying out diffrent woods he wants to cut for his diffrent projects. And we ran into an interesting situation.
He brought up a bunch of samples of hard woods and all cut perfectly except the 'Santiagos(sp)' Mahogany simply would not cut through with even a score line on the bottom, the Honduran Mahogany on the other hand cut like a knife through hot butter.
It was 1/2" thick using a 2.5 inch lens. the Honduran worked great at .8 speed 100% power The other we took all the way down to .1 speed at 100%power and still nothing but a scorched score line on the top of the wood.

Just curious if any of you wood experts out there could explain???

Sandra Force
01-09-2008, 10:31 AM
The 2 things that I see affect the way that wood cuts is grain and water content. If the wood has much water content it is very hard to cut. Mixed grain woods like cherry with a lot of pitch and twisty grain are harder to cut than maple, walnut etc with straight grain and little to no pitch. The more cured the wood the better it cuts for me.:cool: If Eric has a piece that he wants to ship to me to test we can run it on the big lasers and see what they do. Have him pm me if he wants to.

Eric Fuller
01-09-2008, 10:40 AM
Heya Angus, thought I would chime in. First off, thanks for everything yesterday! Lemme know if you ever get that puzzle apart :)

The Honduras Mahogany cut fine like Angus mentioned. I had some Phillipene Mahogany (AKA Luan) and it just wouldnt cut. The bottom showed the same pattern no matter the PPI, strength or speed...small areas where the laser had gone through. I noticed that the endgrain showed a lot of small holes running along with the grain like you see with wenge. My theory is that when the beam hit this air picket, it filed up with smoke and diffracted it.

I still have the piece we tried to cut and I'm going to crosscut it later in the shop today. I expect to see a ton of charring and damage where it hit the air pockets and dumped the energy into the wood.

EDIT: just saw our post Sandra. All th wood I brought is kiln dried and it's super dry around here right now so I expect it was 6-8% which should be fine. I'll cut part of the plank today and post my results. I still have a clean plank of the same thickness, so if you're really interested I can send it. Angus and I cut some .125 wenge just fine, so I suspect that a more powerful laser would zip right through it.

Sandra Force
01-09-2008, 12:01 PM
I have some .5 and .75 luan and will cut it and see what it does and should give some idea on if it can be cut and the settings.

Joe Pelonio
01-09-2008, 12:05 PM
Some of the mahogany woods just will not cut. I was doing some dash work for a guys old sports car and finally gave up and had him look at other woods.

It would merely char and smoke no matter what the settings, even with wet paper towel on it.

This was an African Mahogany.

Mike Mackenzie
01-09-2008, 1:07 PM
I believe it has more to do with the oil content than anything else.

Eric Fuller
01-09-2008, 3:23 PM
I think oil makes a difference, but we cut the same thicknes canarywood no problem. Luan has very little oil; almost none compared to canary. So, while I think it is a contributing factor, I don't think it was the problem in this case.

Sandra, I'd be interested to see how your luan cuts. Please check and let us know if there are visible holes in the endgrain.

Mike Mackenzie
01-09-2008, 6:48 PM
I was referring to mahogany not Luan I have noticed Oily woods are much harder to cut.

Eric Fuller
01-09-2008, 8:38 PM
Yeah, I can believe that for sure.

James Stokes
01-10-2008, 7:57 AM
I have the same problem with oily woods, If you do not have the power to get through in the first pass you will never get through.