DISCUSS Laser NO GO Material #5: Polystyrene Foam

[heyheymama]

Taking @Photomancer’s advice and breaking out each of the Hateful Eight No Go materials into its own thread. Less for me to moderate. Off the top of my head…@pinewoodnut, @talkers, @tomthm, @motopilot, @PearceDunlap, @merissa, @JoshW, @gbeauw, @somecallmery, @bpamplin, @BLOOM, @Kati .

https://dallasmakerspace.org/wiki/Laser_Cutter_Materials

Material: “PolyStyrene Foam”
Danger!: “Catches fire”
Cause/Consequence: “It catches fire, it melts, and only thin pieces cut. This is the #1 material that causes laser fires!!! (Commonly known as Foam Core board) Also known as the white foam that cups and coolers are made of, or the Pink and Blue Sheets found at the hardware store.”

EDIT: Click “like” if original wording is still OK.

[StanSimmons]

I’ve seen people cutting up to 3" thick sheets of the pink foam with ok results, and 1" pink/blue with good results and no fire.

Is there perhaps a particular brand/speed/power that is problematic?

[kbraby]

My understanding is that a fair number of foam core board model airplanes have been cut on our lasers in the past. Not aware of any issues beyond a wing that was sucked into the veitilation, not reported, and much later found to be limiting ventilation flow.

[motopilot]

My vote is this kind of foam is OK… like everything else, when watched carefully.

I’ve seen plenty of it being cut on our lasers already. (foam core, and the pink and blue sheets)

EPS (the bubbly white kind) is slightly different than XPS (the pink/blue/foamcore).

[HankCowdog]

Based on my experience with hot-wire foam cutters, XPS (foam sheets) is much denser, and cuts much more consistently than EPS (fused foam beads).

[John_Marlow]

On the very same page you referenced, in the Safe Materials list, number #11 says,

• Foam Core
• any thickness
• Cuts extremely well on the facings. The center can shrink and melt away if too much power or too low a speed is used.

This seems to directly contradict the statement above it on the same page, in the DO NOT CUT section.

@heyheymama

Material: “PolyStyrene Foam”

Danger!: “Catches fire”

Cause/Consequence: “It catches fire, it melts, and only thin pieces cut. This is the #1 material that causes laser fires!!! (Commonly known as Foam Core board) Also known as the white foam that cups and coolers are made of, or the Pink and Blue Sheets found at the hardware store.”

[John_Marlow]

@StanSimmons

I’ve seen people cutting up to 3" thick sheets of the pink foam with ok results, and 1" pink/blue with good results and no fire.

Is there perhaps a particular brand/speed/power that is problematic?

Unlike the pink/blue foam, the “foam core board” has paper facing on both sides. That could contribute to the problem.

FWIW, The MSDS states:

Primary combustion products are carbon monoxide, carbon
dioxide, styrene, sulfur oxides, and hydrogen sulfide.

Problem is, without an industrial chemist or toxicologist to decipher this, it’s not obvious whether it’s in sufficient quantity to be concerned.

[Photomancer]

At least for one contaminate there are simple CO detectors. It isn’t unreasonable to put one near each machine. It will detect any leakages in real time. They are cheap also.

Could also get one out inside laser and test various materials for CO: in machine and and outside at same time which would validate evacuation efficiency.

Florine detection strips $49

This meter does a range of chemicals

[motopilot]

That’s exactly why we’re reviewing the materials lists…

[John_Marlow]

I apologize if I came across as critical. I didn’t mean to be. I only intended to point out the inconsistency to assist in the review.