I've got one, looks same model. Worked superbly with white EPS - tried it up to 200mm thick - but struggled with grey of any thickness over 100mm prob because the graphite powder in it seems to rob the heat out of the wire. Because with grey it wasn't so much 'hot knife thro butter', we had to push harder, which broke more wires and bent then into a curve so it wandered a bit.

Also tried with aluminium foil faced Celotex - useless, as the aluminium disipated all heat, poss stole current too. Never tried on other foam plastic insulations.

But it did eat through the hot wires, and replacements were expensive and slow to arrive. So made up our own from lengths from www.alloywire.com - back then tommander@alloywire.com was very helpful with advice. Their RW41 was super duper space-tech ‘rene’ alloy, bit expensive; their RW118 is superior Nichrome; RW118 @0.3mm diam and RW41 @0.35mm wires were recommended, and we could have experimented to optimise that.

Used electrical eye-type terminals crimped over the doubled-over wire end. Vital to get the length betwen eyes exactly right.

Possibly thinner (higher resistance = hotter wire) could have done better with the grey EPS, maybe with a PSU bigger than 200W - some use battery chargers or car batteries for DIY cutters.

There was lots of discussion on GBF - search for it. Anyone else got experience of these? I'm not disposing of mine, tho haven't used it for a while!