Hi Rachu!
I must admit, I was confused at just what "expanded polysterene" was ... In the States it's called 'Styrofoam' ... I take it You are cutting it to shape with a knife or saw of some sort?
If, by chance, You're heating up a wire and "cutting" it
PLEASE be careful of the fumes!! they are poisonous! I suppose if You breath enough, they could kill You outright, but, possibly worse, it accumulates in the body and can effect the brain! (kinda like asbestos does to the lungs) I think that's what caused my mom's untimely demise ... she had the habit of standing over the stove, and heating up a wire to "cut" the Styrofoam ... (I think she was using it as bases for flower arrangements she used to do) her distant memory was OK, but her short term memory (as in ten years and less) was completely scrambled ... I'm not sure if it was early onset of "oldtimer's" but from what I've heard, breathing those fumes sure didn't help!

A simple fix would have been to do the "heated 'cutting'" in a better ventilated area ...
Oh,
GET WELL SOON!!!
