Superpiper,

For this reason one should not use PTFE to PTFE pads as one tends to bed into the other.The standard practice in the industry these days is to use SS plate at the top and PTFE pad at the bottom, this also prevents dust accumulation as the PTFE pad should be designed smaller than the SS bearing plate on top.

Incidentally I have also seen ATCO pads (used as acoustice isolators) deeply embed themselves onto the steel beams supporting them,effectively they end up as line-stops and if they are chemically bonded to the u/s of the shoes they in time shear off altogether.

Regards
A