[pointcloud]

A very small cyclinder will work with this foam you are useing.. No need for a 6" diameter... A 6" at 150psi has over 4200 psi on the piston face?

A 1" will have almost 120 psi, what is WAY more than you will need to cut this foam...

Your bottle jack will cut it with it's own weight..

All of the above is assuming sharpness of the balde is at it's best..