The general rules for foam pads;
Pad size; with smaller pads you gain increased control and manoeuvrability. Smaller pads generate more friction (heat) with a PC, which breaks down polishes by generating energy over a concentrated area. The random orbiting motion of the PC generates the most power in the centre of the pad (i.e. area of a 6.5 – inch pad is 33 – square inches compared to the area of a 4 – inch pad, which is 12.5 – square inches) This additional cutting power will facilitate the removal of deeper imperfections
The opposite is true with rotary buffers. The speed of the outer edge of a smaller (radius) pad is slower than that of a larger (radius) pad. This helps reduce the amount of friction generated, which makes polishing tighter areas much safer.
• The coarser the abrasive, the faster the cut
• The more aggressive the pad, the faster the cut
• Wool cuts faster than lamb’s wool, foamed wools are next, then foam.
• Foam pads generate more friction induced heat than wool pads
For more information see the “Foam Pads” article; one of a collection of detailing articles I’ve written for DetailingWiki; a series of informative, knowledge based, unbiased articles dedicated to automotive detailing