[DaSchlange]

I cannot see why it would be... I mean, if you're gonna do it in the doors or something that would put the foam in the way of mechanical parts moving it would be a problem, but simply putting it in an empty space in between panels wouldn't cause any harm. That stuff won't push out metal though. The only other thing I could think of is if there is an acid in that stuff that would cause the metal to corrode over time. But I doubt that as well. I would do it myself, not a bad idea. Plus you'll have better insulation for cooling or heating...