Why is the polishing compound so hard?
It is a solid compound. There is a fallacy that exists about polishing compounds and waxes. It is the concept that “more is better.” That isn’t really true. When using waxes and polishes, it is often more effective to use a more conservative amount and then repeat rather than have to remove an excess. If you apply too much polishing compound to the material being polished, the excess polish coupled with the speed of the tool will create swirl marks on the surface being polished. Removing those will require several clean felt or cloth polishing wheels.
