Thursday night, John tried to cut some PETG plastic, and it smelled so bad we assumed it was going to kill us all. Fortunately, that isn’t the case. Praise the Internets!

PETG (polyethylene terephthalate glycol)

PETG usually comes with a thin, plastic, film masking on both sides. It is not brittle (it will bend quite a bit before it cracks), and PETG parts will not crack or break easily, even if you drop them. PETG is less rigid than acrylic, and is somewhat soft.

Laser-cut PETG parts tend to smell, so you might have to air them out for a few days and wipe off any dust and residue with warm water.

hmm, we tried a chlorine test and it seemed to have chlorine in it from that. Although when I looked at the chemical formula I didn’t see chlorine in it’s structure. Need to test this with a different piece of wire. I don’t think PETG is a very good choice for laser cutting, as may have been noted, as it is a thermoplastic with a fairly low melting point and thus melts quite a lot when ablated with a laser.


I agree, it definitely melts a lot. I don’t think thinner material would be a problem, and the material’s flexibility might be a plus in some applications. I believe John ordered it from Pololu, and the text I posted was ganked directly from their site. Is the chlorine test definitive?

You know, I’m not 100% positive if burn tests are definitive. There might be a possibility of several compounds and elements have the same flame test color, but I’m not much of a chem person! I’ll research a bit about flame tests and report what I find.


I think this might be one of the limitations of having a cheap chinese laser cutter, apparently you need to modulate the laser pulse frequency in order to avoid the yellowing // extreme meltyness of the edges.