Rotary Polishing Guide

Rotary Polishing Guide

This simple step-by-step guide will explain how to use your circular / rotary polisher to remove paint imperfections and rapidly improve the quality of your finish. Keep in mind, circular / rotary polishers offer complete removal of scratches and swirls, but there is a learning curve. If you are inexperienced with machine polishing, start with a dual action polisher and become familiar with the process. Once you become comfortable, graduate to the circular / rotary polisher.

What is a circular / rotary polisher?

A circular / rotary polisher is sometimes referred to as a rotary or high-speed polisher. It's called "circular" because the head spins on one axis. It spins typically from 600-3000 RPMs. This single motion allows a circular polisher to level the clear coat that surrounds a scratch so that the scratch's "edges" disappear. Professionals who want to completely remove a deep scratch must use a circular polisher.

The heat is on! Circular / Rotary polishers get much hotter than dual action polishers because the pad is spinning at a high speed. You MUST keep a circular / rotary polisher moving at all times so this heat doesn't concentrate on one spot. It will burn through the paint in seconds.

You can minimize the risk by practicing on scrap car panels before you attempt any work on your own vehicle. You can pick up old parts at your local junk yard for a fee, but it's definitely cheaper than repainting your vehicle!

Popular models of circular / rotary polishers are the FLEX PE14-2-150 Rotary Polisher, FLEX L403 VRG Lightweight Circular Polisher, the Makita 9227C Rotary Polisher, 3M Electric Variable Speed Rotary Polisher, and the DeWalt DWP849X Variable Speed Rotary Polisher.

A Few Facts about Clearcoat

So you may understand the thickness of clear coat, think of the cellophane wrapper on a pack of cigarettes. Remove it and press the two sides together. This thickness represents the depth of clear coat that protects your vehicle's pigment layer. The outer surface of the clear coat is the "hardest" and "densest" and is impregnated with the critical UV protection. This surface - assaulted by bugs, bird droppings and acid rain - gets worn away revealing the softer, underlying clear coat. This makes clear coat "fixable", meaning swirls and scratches can be removed with a polisher.

The Paint Facts - Typical Industry Paint Thickness Specs.

E-Coat 1.3 mil - Electrocoat is an anticorrosion coat applied to both sides of the steel to prevent corrosion (rust).

Surface Primer 0.7 mil - Initial protection layer with texture to assist the pigment layer in bonding to the metal beneath.

Base Coat 0.6 mil The basecoat is usually 0.5 to 1 mil thick (1,000 mils equal one inch).

Clear Coat 1.9 mil - The clearcoat provides gloss for that "wet look," plus physical protection from the elements, including ultraviolet rays. The clear coat is usually between 1.5 and 2 mils thick.

As you can see, the clear coat is very thin. So, while you can polish out scratches, you must use great care with a circular polisher to avoid burning the paint.

Polishing Tips

  • First and foremost, keep the polisher moving at all times. Never let a circular polisher rest on the paint. It will burn through the clear coat.
  • Work at a slow speed, between 1000-1200 RPM. A circular polisher is capable of getting very hot, especially at high speeds. While a little heat can make the clear coat more malleable, too much will burn the paint. Keep it slow.
  • Work the pad flat against the paint or with the back edge of the pad tilted very slightly upward (that's the edge closest to you). This position will help you avoid dragging the edge on the paint, which creates holograms or what some detailers call "cookie-cutting".

What problems can a circular polisher correct?

A circular / rotary polisher can remove almost any scratches or swirls and most oxidation, as long as they do not penetrate beneath the clear coat. A good way of assessing a scratch is to run your fingernail over it. If your fingernail catches in the scratch; that generally means it is too deep to be removed without professional help. Scratches and swirls that extend through to the color coat will require repainting or a touch-up at the very least. Do not attempt to remove these scratches because you can remove the entire clear coat, resulting in paint system failure.  

That said, many detailers enjoy the high speed performance and quick paint correction of a circular / rotary polisher. All it takes is practice and a steady hand to master the art of machine polishing.