Is fire bad?

I know this is a silly question, but I’m experimenting with different materials and one material I use when the laser hits it a small flame appears. It doesn’t catch the whole wood on fire but I do see a flame. It isn’t tall and the air flow directs it downward so it doesn’t look like it touches anything and is only there when the laser is cutting. Is this bad? Should I be adjusting my settings so that this doesn’t happen, or is there even a way to adjust so this doesn’t happen?

Should I be worried or is this common with different types of wood? Please let me know.


Depends on the material but usually isn’t a problem. It says even in the manual, you may see a small, candlelike flame - it should keep moving with the cut though and not linger behind it.


Ok thanks, I wanted to make sure it was not a “holy crap stop what you are doing immediately and turn the machine off” type of situation :slight_smile:


Some materials are prone to flaring including some species of wood. Cardboard is probably the worst I have seen personally. The air assist fan that blows forward from underneath helps blow the flame out (except cardboard because of its corrugated nature).
The cardinal rule is to be in the same room with your laser and pay attention. If you encounter a sustained flame, raise the lid on the glowforge, and that will immediately cancel the operation, and you can put the flame out.

Standby remedies I use are;
A damp rag you can drop on it
A squirt bottle of water
A fire extinguisher
In that order.


Thanks for the help - much appreciated!


I don’t know about others but I had a lot if problems with Mahogany flaring like that. It can scorch or burn the wood not bursting into flame but like coals under the blower can burn away part of your design.

I have found in such cases getting the wood wet but no free water will not reduce the power at the point of laser contact very much but it does reduce the flaring, and where before you get the scorching and even charcoaling the water can nearly eliminate that problem as the wood needs to dry before it can scorch.


I also find that flare ups with woods are more common when you aren’t cutting all the way through. Flames can sometimes be a tell that you didn’t get a complete cut, especially with exotic hardwoods.


I keep one of these nearby, just in case…

one other thing that can cause flare ups is when you have masking on a material that has an area that isn’t completely sealed to the material. a little air bubble can cause a little flare when the masking burns.


Last resort:

Oh and one thing I recently discovered is that if you have soaked the piece supposedly finished in furniture oil giving it another pass with even a light engrave needs to be very careful. It flared pretty constantly but not as much as one would think. I had it at 40% and did another pass at 10% to clean up all the black that was more gunk than char, but the wood was definitely darker even after going through the cleaning proceedures.

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Not at all a silly question. :slight_smile:

if you start seeing sustained flames on materials that did not flame up previously, it may be a sign that you need to clean your air-assist fan/scoop.