So, from what I’ve gathered your everyday plywood is probably not good for your laser. But is there any reason not to engrave the top of it? (Assuming that its untreated)
I would think that that would be fine. As long as you avoid knots in the wood and you wouldn’t be cutting any glue I think it would turn out quite nice!
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For plywood, I realize all different types. But other then the different thicknesses of the veneers, what worries of the glue should I have? Or what glues should I look to avoid or figure out that it contains the bad ones?
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Im not so sure what glues to avoid but im sure some glues release harmful fumes when they burn. However i think that it would be such a small amount the air vent should draw it away. @dan says the materials from GlowForge will be laser safe glue so I don’t think they will release harmful fumes but I don’t know how they are made differently.
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Anybody want to do a MDS lookup on a sheet of Home Depot plywood and figure out if it’s safe or not? [aside from the results and quality… is it safe?]
I think its a viable question. I guess I should volunteer, since I am curious.
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I cant wait to see what you come up with lol
I would suspect that any PT ply would be very harmful but I hope the A/B Birtch they sell is laser safe
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PT ply? A/B Birth? I’m sorry, please define.
I posted a question online; but I will go in the next day or two and ask somebody at the store. See what they can tell me.
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With shipping to Canada, I am certain buying from GF will not be cost effective for me. Also if I want some custom presses, or if I can grab some on a sale locally, I’d rather that.
I found a local supplier who will take a 5x5 of Baltic birch ply(the super thin ply type) and rip it into 20" x 5’ strips for me(ok not 20", 19 whatever after kerf). That is way more useful with the pass through slot. Also shipping that long of an item from Seattle to Canada just won’t work.
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Here’s what I found after some googling.
PRODUCTS: Plywood and Composite Wood Panels Produced with Urea Formaldehyde and Melamine-Urea Formaldehyde Resin Systems. Includes Laminated Panels and Panels with a Cured Water Based Pre-Finished Coating…
Fire smoke contains hazard chemicals such as carbon monoxide, aldehydes and other toxic materials.
So help me translate… Carbon monoxide, while usually not something you want to breathe, would be filtered out and vented… not an issue?
What about formaldehyde? Are these the deathly toxins? or are they less objectionable?
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sure! PT = Pressure treated! Nasty stuff… A/B refers to the grade of the wood. A is clear no knots, b has filled knots and or voids in the wood and then you get down to d type ply wood which is “rated sheating” and just ugly “full of knots” most of the time.
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I would think the formaldehyde is certainly something you don’t want to breath and I plan on hooking up a pretty good venting system so that all the fumes are sucked out.
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According to the CDC, formaldehyde can cause discomfort in the eyes and nose if it’s levels reach 0.1ppm. However, some people experience no symptoms at that level. It would certainly not be deadly in the amounts you would get from Engraving across a replaced knot. Also, I found a site that showed an experiment someone did that showed that activated carbon filters do capture it, so as long as you are not Engraving the entire top layer of wood off the whole sheet, you should be fine.
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Finding plywood and MDF without urea formaldehyde is easier these days. Look for “NAUF” or “zero UF” . But I am curious if the replacement glue being used is laser able.
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Just an anecdote… I used a friend’s Epilog laser to make a clock dial, and for some reason I wanted it 4 mm thick. There was some plywood in a local place that was, and was called marine plywood. The glue, or middle layer, which I thought at the time was to make the stuff more easy to bend over a form, but I’m told is waterproofing, seemed to me to be rubber like. In spite of good venting and air flow there was major smoke and flame.Don’t do it !
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Thanks guys for the input. 
I’ll just have to be careful!!
Every house with gas forced air heating and gas water heater/dryer emits carbon monoxide.
As long as it’s not in a contained area you’re good.
With anything, it is a matter of concentration. Oxygen is toxic above certain levels.
Standing around the campfire, even your charcoal grill exposes you to carcinogens.
Most fatalities from fire is not from burning to death, but smoke inhalation. Carpet furniture and curtains are the biggest culprets. Arsenic formaldehyde and cyanide are all around us in different forms - that’s what we need to be aware of while we turn materials to smoke.
I would like to hear from experienced laser users about episodes of flair ups in their equipment.
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Yes, it seems that the only situation that would expose us to any significant concentration of noxious stuff would be when we need to fling the lid open to deal with a flareup, since the filter or vent will keep the in-room concentration of these VOCs low enough to be inconsequential under normal circumstances.
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