If we keep in mind that polishing is a matter of science then we can dissect it. Let look at how heat affects the polishing process. Heat is a byproduct of the friction that occurs between the pad, the abrasive, and the paint. Heat is actually the energy lost according the The Law of Consevation of Energy.

So let’s look at what effects heat has on the process.

What effect does an increase in temperature effect the breakdown of the abrasive, or the rate of its break down? Like most metals, aluminum oxide (common abrasive) will become more malleable with an increase in temperature. However it would have to reach temperatures that are likely high enough to damage the paint before any real difference in application are noticeable.

In fact this can be proven by heating the abrasives with a heat gun. Aluminum oxide has a melting temperature of 3761 degrees F! While it will distort prior to reaching this temperature, it will not with any temperature we are capable of inducing with foam or wools pads on a painted surface. Simply put, the heat we are capable of producing while we polish is going to have no noticeable impact on the abrasive.

What effects does an increase in temperature have on the paint? Modern, catalyzed clear coat paints are chemically cross linked. You cannot heat them up and cause them to reflow. Drastic increases in temperature will damage the affected area permantely. Also, as the temperature of the paint increases, the paint will expand or ‘swell’.

This is unwanted because as the paint expands the sharp sides that form the sharp edge pull apart, which can round the edge. For example, place your hands together like you praying. Now, keeping your finger tips touching spread your wrists so your fingers intersect at 90 degrees. Your finger tips represent a sharp edge. To represent the paint swell, spread your hands apart. The gap between your fingers represents what is left of the sharp edge. The gap will be bridged by a rounded edge. This happens at the microscopic level, which can make defects literally disappear until the paint returns to its normal shape.

How does heat affect the pad? There is some evidence to suggest that polyester becomes softer with an increase in temperature. At first this seems like a step in the right direction, but this can easily be compensated with the huge variety polishing foams available on the market. Softer is not always better, so it could even be worded that if excessive heat is used, you might have to step up in aggressiveness to compensate. Of course the amount of change in the foam is going to be very dependent on the particular formula of that foam.

How does heat affect the lubricants in the polish? While I could see the argument that an increase in temperature increases the flow ability of the lubricant (which may or may not be a good thing de pending on the design of the polish) the increase in temperature will cause the lubricant to evaporate quicker. This could cause the polish to dry prematurely.

If we look at the areas we examined: The paint, the abrasive, the foam, and the lubricant, we have one case where the result is negligible and three where the result is negative. The abrasive will not break down faster or more evenly because of a temperature increase, nor will the paint reflow or become more workable. To me it is pretty evident that increase in temperature serves no functional benefit and several drawbacks.