Extruded polystyrene

I am thinking this might be a “bad idea”. This may be a fire risk…
Can 1” thick extruded polystyrene safely be cut on the Glowforge?
If yes, what settings would be best?

If not mistaken, I don’t think any 1" material can be cut even if you’re using the pro. You would probably need at leats a 150W laser to cut that thick of material, and that might not be enough.

The focus range of the Glowforge lens is 1/2" so cutting 1" material is not going to be an easy proposition.


Thank you for speaking up. I had thought about the thickness concern. To “deal with” the extra thickness might the crumb tray be removed? Possibly set the extruded (not expanded bead board) polystyrene (foam board) on the sheet of plywood. This material is typically used for insulating cement blocks. It is sometimes cut with a hot wire but a handsaw works or a utility knife. It is not dense at all. It may be too flammable. (One of my concerns mentioned before) I am curious to know if anyone out in the community has cut this material with their Glowforge and what settings would be good to use.

There have been quite a few posts regarding polystyrene (Search results for 'polystyrene' - Glowforge Owners Forum). That being said, the focus range remains 1/2". The surface you wish to engrave or the material you are cutting must be within the focus range. You can remove the honeycomb tray and elevate the material, but the lens still has a 1/2" focus range.

Thank you for this suggestion / direction. I’m still relatively new (1 1/2 years) to this machine and the forum.

To clarify, YES - you can remove the crumb tray and engrave on things up to 2". What you’ll need to do is add something to the bottom of the glowforge to bring the top of the item you’re engraving up to a height a little above the thickness of the tray, but less than 2". (I use scraps of plywood.)

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I’m continuing to build a base of understanding on the use of this machine. Thank you for your insight.

In your response you specified “engrave”. I’m wanting to “cut” 1” styrofoam (expanded through extrusion not “breadboard”), not engrave. Is removing the crumb tray only for engraving on larger items or can it be removed for cutting too? If I’m cutting without the crumb tray do I need to “protect” the bottom of my machine? Do I need something like a sheet of 1/4” plywood under the material I want to cut? Thanks for your time.

Spell check changed the word “bead-board” to “breadboard”. Bead- board was the intended word.

the maximum cut depth is 0.5". You will not be able to cut through 1" material.

you might be able to engrave a pattern in the foam and then use that pattern to cut it manually with a blade or hot wire.

the crumb tray can be removed to fit larger or oddly shaped materials into the machine for any available operations, but that does not change the focal length of the laser; all cutting and engraving happens in 0.5" area directly underneath the laser head.

no. the stainless steel plate underneath the crumb tray is all of the protection your machine needs.


Thank you for your responses to my questions. Much appreciated!

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I wanted to stress that if you actually plan on doing this you need to watch it THE ENTIRE time the laser is firing… with your hand ready to open the lid and extinguish the flames. Styrene melts instantly, burns almost as quickly and sticks like syrup all the while the flames keep spreading… it basically turns into napalm when ignited.


I have a basic understanding of the properties of polystyrene. Researching styrofoam on the GlowForge before doing my own “experiments”. My risk aversion is pretty high. I do not want a fire or to fill my unit with fire retardant from my fire extinguisher!

This is not a “must do” but a “what if I could do” interest.

Thanks for the word of caution. I heard you and will remember the good advice.



It won’t cut 1", only engrave on 1" if you remove the crumb tray.
Honestly, for me personally (also risk aversion pretty high lol) I would not do this at all.
But, with that said, maybe there are some other ways to tackle this. Maybe if you approach it from a different angle, you can get the results you are looking for.

For example, you can’t engrave on a large glass, but you can cut a template and then place the template on the glass and paint or etch it. Know what I mean? (More than one way to skin a cat!)

However, without knowing exactly what you are trying to do, I can’t say for sure what the answer might be. Just wanted to suggest looking at all of the options possible. Hope you find what works.


I do not have any pressing need to cut polystyrene on my Glowforge. Based on your thoughts and input from others I am no longer considering even experimenting. I like polystyrene as a base material for sculptures but totally get that he Glowforge is not the ideal tool to fashion layers of foam for building models of any particular design. Thanks again to the users who contribute to this forum!

You can cut thinner layers of foam, or whatever else laser safe, to stack. A lot of people even do this with 1/8” plywood to get 1/4” as it tends to be more reliable.

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It cuts easily and cleanly in what I would call “normal” thicknesses, I’ve used 1-2mm. Many materials (acrylic most notable) can flare up, especially in thicker sizes.

The point here is that the machine is optimized for common materials (mostly as sold by Glowforge themselves) in reasonable sizes, up to 1/4" but even that can be problematic. I won’t use 1/4". It is physically (optically) not designed for anything thicker.

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