How To Care For Today's Car Paint!
One technical issue not often discussed in polishing is heat. Back when we were polishing lacquer, the heat was seen as beneficial to the polishing process. Today's paint is, in essence, plastic; heat is the enemy.
Compounds have come along way from the days of cornstarch and kerosene. They do, however, still contain water, oils, abrasives, and in some cases, solvents -- though, Optimum's Hyper Paint Correction System (HPCS) contains no solvents and 2 times more water then oil. When a manufacturer claims water based it just means there is more water than oils and solvents, not that the solvents aren't existent.
Paint manufacturers agree that 140-150f is the upper heat limit that should be induced from polishing or compounding. Another way of looking at it is as a maximum temperature differential of 80f . This induced heat is unlike that generated by the affects of the sun, a paint booth or the radiant heat from the engine compartment. Heat induced by polishing is very targeted and escalates rapidly. This puts stress on the paint it's not equipped to handle.
Four user controlled actions affect heat generation the most: pressure, pad rotation speed, arm speed and the condition of the pad.
Heating the paint (I'm using the term paint, but in this text it's fully interchangeable with Clear Coat) creates many negatives that are experienced as you're working, and some that show up later.
First and foremost, heat swells the paint . Remember, the paint is essentially plastic. This can actually cause cuts or scratches to be driven further down into the paint.This same heat softens the paint, reducing the effectiveness of the abrasives. Imagine sanding an ice cube vs sanding a marshmallow.
Seen under a microscope paint is like a sponge, and the oils and solvents get pushed into the pores of the paint; often mistaken as a polish acting as a "filler. This oil injection, combined with swelling, conspire to have the same effect as Botox has on skin; temporarily hiding wrinkles, or in our case minor scratches. This effect does not go away as soon as the paint cools down. That injected oil/ solvent mix stays in the matrix of the paint keeping it swollen. Over time it will work it's way back out, returning the paint to it's natural state, this can be as fast as a few days, and up to many months. The injected oils are removed through erosion (for lack of a better term) by water, emulsification by soaps, and evaporation. This is not to be confused with the filling affects of a glaze.
Over the long term this can cause paint failure. All too often we see paint failure as lines on a surface that look like a pass a polisher made a few years back.
Pad maintenance has a big effect on both their ability to cut , but also heat generation. If your pad is loaded with product, compound or polish residue, and paint residue, the cut of the pad will be reduced and more heat will be generated.
Pad choice has a big effect on heat generation as well. For cutting, a good old fashioned big thick wool pad is actually what runs coolest in most cases on a rotary. There is a lot of air movement in the pad, and on the surface keeping it cool. Where the "old school" pad get its bad rep from is mainly from being misused. Pads overloaded with product and paint residue, user error and poor pad maintenance is why those types of pads aren't highly regarded.
Foam pads on a rotary have been used for many years. Flat pads create lots of drag that translates into heat. For the rotary, waffle pads have been popular for a long time because of the reduction in heat. Again residue control is important, but the pad will generate less heat, while cutting more than a flat pad made of the same foam. A few reasons behind this: first the pad stays cooler; cooler pads translate to better cut. Second, waffle pads have more contact area then flat pads, unless the car is perfectly flat. The pad will conform to the surface better.
On a DA, heat in a pad can come from the tool as much as from the friction of the pad against the paint. The Velcro that holds the pad to the tool is a series of many little hooks, and because of the action of the tool, there is a lot of friction between those hooks, and this can cause a lot of heat, to the point of melting the pad internally.
For the DA, the face, thickness and materials chosen are seemingly limitless. We have various types of wool, foam, felt, micro fiber and hybrid pads, all with highly engineered materials. We also like to vary the thickness of the pads, we carry several different options.
Knowing the science behind a polish is what distinguishes us as car care experts. After learning about ramifications of careless polishing, will you think twice about who takes care of your car? Take it to the experts, take it to us!
Reference: Yvan Lacroix with David Ghodoussi (Optimum Polymer Technologies), David Patterson (Lake County) , Ron Ketcham and Andrew Kidd (Sherwin Williams).