SpudFiles

If you're using closed-cell foam, when you put pressure in the pilot it will compress the foam and when the piston opens it will slam in to the already compressed foam. The bumper could still work fine but the energy the piston would exert on the foam to compress it will have been loss as the foam is already compressed.

You need to use open-cell foam so that the pressure can equalise on all sides and not compress it.

Yeah it is open cell foam, so I'm good there, I had tried closed cell at first an I smashed it a few time with a hammer first to make sure it would withstand and it flattened out. This rubber stuff withstood the hammer

holly cow! great damage pics