Flame testing foam board, DTFB, EPA foam, & felt pads (Edited)

Based on an earlier discussion regarding the Chlorine-content of DTFB and other paper-backed foam core:

I finally got around to flame-testing a number of potentially hazardous materials…

But first, the standard disclaimer: This is a hopefully helpful, but non-authoritative post. You should always test all unknown materials before placing them in any sort of laser cutter!

Every variety of foamboard / foamcore (DTFB and others) I had sitting around tested clean – yellow flames without a hit of green = OK

Those dirt-cheap EPA foam anti-fatigue mats from HF – Yellow flame with black soot, but no green = OK

Control test: PVC insulation on electrical wire – bright green flame = BAD (as expected)

EPS foam from two of my RC planes – Yellow flame, no green = OK

The only material that I thought would test positive but did not were some heavy-duty felt pads with a thick adhesive substrate. I expected it to be bad due to the smell I encountered when lasering a piece last week – it had the tell-tale burning plastic smell I associate with accidently melting PVC with a soldering iron, etc. I dissected a sample to test the synthetic felt pad, the mystery backing, the super sticky adhesive, and even the waxy paper adhesive cover – all burned yellow (if at all), not a hint of green = OK

Repeated the whole shebang, same results: smells like burning PVC, but no evidence it contains Chlorine. :thinking:

Edited: As @dan points out in another post…

…there are many potential toxic byproducts of combustion. I believe this video only attempts to tests for one. I would not rely on it to determine if a product of unknown composition is laser compatible or not.


Super helpful! Thanks @dwardio ! :grinning::+1:

I’ve got to see if hubs has any copper wire lying around out in the garage…I’ll eventually need to run some tests on the materials I plan to use as well.