Medium Cut Polishes

A medium cut polish handles moderate swirl marks, light to medium scratches, and the compounding marks left after a heavy cut stage. Scholl Concepts S20 Black, for example, is rated to cut defects including sanding marks up to P2000 grit before breaking down to a high-gloss finish. Deeper scratches that a fingernail catches require a heavier compound first. Light haze or fine marring on well-maintained paint can usually be addressed with a medium cut in a single pass.

Yes, for most daily-driven cars with moderate swirling a medium cut one-step polish is the practical choice. Scholl Concepts S20 Black is a pure diminishing abrasive with no wax or fillers, so what you see after buffing off is the true paint condition. On an unknown car, start with a Rupes Yellow foam pad and S20 Black on a 2 ft by 2 ft test spot. If the result is insufficient, step up the polish before reaching for a more aggressive pad.

Spread the polish across the section at speed 1 to 2 with a quick arm movement first. Then correct at speed 4 to 5 with a slow, steady arm and 50% overlap per pass. Four passes is standard on most paint; step up to five on badly damaged paint. Apply maximum 10 to 15 lbs of pressure, roughly a firm handshake. More pressure causes heat that flashes off the polishing oils and kills the abrasive before it has finished working.

Both sit in the medium cut range. S3 Gold XXL is suited to moderately defected paintwork where S20 Black alone may not be aggressive enough, particularly on repainted panels. For heavily swirled or aftermarket-finished paint, plan on two full cutting sets with S3 before a finishing pass with an ultra-fine polish such as S40. S20 Black is the go-to for a single-stage correction on smooth original paint in nine out of ten cases.

Only if the paint actually needs correction first. A ceramic coating bonds directly to virgin, decontaminated, unprotected clear coat. If you use a medium cut polish, follow it with a refinement polish using a pure, filler-free formula, then wipe down with a panel prep spray that contains surfactants. IPA alone is not sufficient as it leaves polishing oils behind. After the wipe, test the panel with water: fast beading or sheeting means oil is still present and the panel needs further prep.