As far as strapping them, probably just nylon ties that can be easily cut with a pair of nippers when the socks need to come off, then easily refitted with new ones.
I have to do some digging, but in another life I had a number of aquariums. The filters on some used foam and I seem to remember plastic webbing that went inside some of them. Theres also a perforated plastic panel available for aquarists that is used to divide the tank in half. It is quite flexible and easily cut to size. So, first stop will be my abandoned fish room and then, if no luck, the tropical fish store.
Ray