Reflective surfaces?

[joe]

@dan explains it best below, but things that are reflective to visible light aren’t necessarily reflective to the Glowforge, and visa-versa. So glass and normal mirrors should be fine. Hard Drive Disks, not so much.

Favourite materials

So you know how on a half-dozen occasions someone’s said “don’t cut glass mirrors!” and I’ve said “those aren’t mirrors when you’re a 10600nm photon.” Or similar. Basically what you think of as a mirror, isn’t, to Glowforge wavelengths. Well, hard drive disks are VERY VERY GOOD MIRRORS to Glowforge, and I would strongly recommend not putting them inside. Glowforge is designed so that it won’t cause too much havoc, but it’s not going to do anything good either.