Expanded polystyrene - safe to cut?

[Pete Andrew]

Has anyone cut expanded polystyrene (that packaging stuff) with a laser? I seem to remember as a kid cutting the stuff with a hot wire and all of us really rather enjoying the smell..... Nowadays I'm a little more careful. I'm wondering if sheets of the stuff be cut with my laser (35 W) into (say) letters or shapes for display purposes, or whether it will just burn furiously in my machine giving off briefly enjoyable but nonetheless deadly fumes..... Anyone tried this yet?....before I do?

[Gary Hair]

I don't know if it is the same stuff but I have been cutting foam-core boards to use as templates. It probably doesn't smell great but I vent outside and don't open the lid until a little bit after I cut anything. I did check the MSDS on the foam core but I forget if it is polystyrene or not, either way, it didn't show any noxious or toxic fumes on the msds.
Google msds and polystyrene and see what you find.

Gary

edit: as for the burning - I would bet if you went high speed, high power and air assist you would have no problems with flare ups or burning.

[Joe Pelonio]

I've cut polystyrene sheet, what you are asking about is the same material but with some air mixed into it. I wouldn't be too concerned about the fumes, but with those softer plastics it's hard to get sharp edges like acylic, it tends to melt and "roll" the edges a bit. The expanded foam version may be worse.

Gary,

When I've done foam core I get concave edges, but after telling people that they have still gone ahead and ordered from me. The top and bottom surfaces cut great, but the center melts and caves in some. Have you managed to cut foam core with straight edges?

[Gary Hair]

Gary,

When I've done foam core I get concave edges, but after telling people that they have still gone ahead and ordered from me. The top and bottom surfaces cut great, but the center melts and caves in some. Have you managed to cut foam core with straight edges?

No, the center does melt a bit. I am just using it for templates so I only really care about the top and bottom, mostly just the top.

I just can't see using acrylic, like others do, for templates - it's way more expensive than the foam core and takes longer to cut.

Gary

[Dave Jones]

I've used corrugated cardboard for temporary or short run templates. Lots of cardboard boxes laying around, so the material is free. I do tend to use acrylic or thin wood for heavy production templates.