Originally Posted by Pleiades

Yes and no. Permatex works slightly differently, it's actually an adhesive, not a lubricant. It will stop the pad moving in any direction (other than obviously the one that works the brake!) Copper slip is slippery by nature and the pad can still move against the piston, pins etc, but will do a job "deadening" the sound.

I do actually use Copperslip on the Z, but only to keep the pins from seizing up, never had a problem with squealing.