I'm hoping you're wrong. I just made a simplified version, which is just the concertina-ed paper without the parallel reverse folds to angle the keyboard up. It

I'm hoping you're wrong. I just made a simplified version, which is just the concertina-ed paper without the parallel reverse folds to angle the keyboard up. Its made from a 96gsm a3 sheet. My reasoning for thinking it's safe is that 451F/230C would probably damage/burn/melt the cheap plastic table it normally sits on.