So that the outer frame did not get pushed away at the bottom, I made two of these multi-segment neoprene-isolated braces for each side:
An advantage of Acoustisorb, compared to fibre glass, is that it does not leave invisible glass fibres on your skin, so it is completely safe to handle. However, it is notoriously difficult to cut, so I built a frame out of MM, into which I mounted a 230mm-bladed 5kg angle grinder. I just did not feel like risking holding it in my hands and trying to cut 1.2m in a straight line a 100 times. One slip and whatever got it its way would instantly be cleaved without notice!
So here is my Madame Guillotine, in its standing position, showing the bed where the foam goes:
Madame Guillotine, with foam in place, ready to be plugged in and started:
