Does polyurethane automatically 'foam' up or do you need to activate it with something. If it dosen't foam up 1m3 or 1000litres sounds quite expensive. I had a look on some suppliers about PU and it seemd to vary from everthing like foam cushions to plastic injection molded parts. Can anyone...
I need a simple and cheap way to fill a large hole (1m3)with something like polystyrene. Are there any chemicals that I could mix that would expand and fill the void inexpensively. The material must harden so that it could be removed at some point. The material could have bubbles in it but...
I have a rocker ohv shaft supported by 3 springs. The first is the pushrod stiffness, the third is the valve stem stiffness and the second is the rocker shaft reaction point. The rocker pivots about this centre point. When I try to calculate the natural of the assembly, I get an incorrect...