Wax or Polish? What is in a name?
Though both terms are used interchangeably, there is a fine difference between wax and polish.
In generally, Polish is a mild abrasive substance which will clear the paint surface of mild oxidation and smoothly micro sands the surface and gives the surface a wet, deep glow.
On the other hand, wax is a protective coating - it covers the micro pores in the paint and seals it and helps the paint to shine. A wax does not have cleaning properties, and applying a coat of wax on a non clean surface is not at all recommended because wax will seal the minor aberrations.
Though generally polishes are abrasive, there are exceptions. meguiars claims that they use a secret polishing oil and their 'pure polish' is non abrasive.
To Polish or not to polish?
As you may have already understood, most polishes are abrasive materials so naturally there will be doubts like why should we use abrasive materials on the paint. The answer is simple - to clean the paint surface and to remove swirl marks, to improve surface reflections and to improve the paint gloss.
Generally, if the car is not used in a heavy polluting environment, you should wax your car once in 3 ~6 months (depending on the wax) and should polish the car in once in a year.
The definition of polish is: "Polishing is the process of creating a smooth and shiny surface by rubbing it or using a chemical action" (from Wiki). Polish is the process of making it smooth by friction, but more often than not, it is not the heat which is produced using the friction which does the work, but the friction itself. Most polishes are emulsions of powered abrasive in a carrier. Heat causes paint dull, so wet polishes eliminate the heat induced by buffing action.
Different polishes have different cutting ability, and this cutting ability determines the amount of paint removed in each hand or machine stroke.
There are different kind of polishes available in market - we must choose a polish based on our needs.
Typically, based on technology, we can divide polishes into polishes which uses 'Diminishing Abrasives Technology' and those which uses 'Non-Diminishing Abrasives Technology'.
I am not going into detail of the difference between these two, but if any guys out there want to know more, feel free to ask.
The market have dime a dozen polishes claiming to work miracles on your car paint finish - we really need to know what we are buying before we try them on our paint surface. For example, the outcome of a coarse finish polish and a fine finish polish are way apart.
Some polishes are specially formulated for machine use, while some are for hand use. the difference between them is the way the abrasive materials in the polish 'breaks-down' during the use. As I said earlier, polish in an emulsion and the carrier act as lubricant too.
While polishing, the abrasive materials break down into finer particles to do the work. If you use a machine polish by hand, the particles may not break down, and may not buff out to give you the shine you are looking for. Same way, if you use a hand polish with a buffer, the particles may break down too easily and you will not get the cutting action.
the polishes are scaled on a grade of 0 to 1, 0 being non abrasive polish and 10 being the most abrasive. Most good polish compound use a mix of silica and aluminium oxide - they are hard materials and the kinetic energy during the polish action makes them abrasive.
For our general use, we do not need to go beyond 4. 1 is a Pre-wax cleaner polish, 2 is final finish polish, 3 is final cut compound, and 4 is heavy cut compound.
Polishes beyond scale 4 are generally called grit sanding materials, and we usually do not need so heavy stuff to work on our paint.
the new advancements in technology have helped many brands to manufacture what generically referred as single polish or single liquid polishing system. These are made with the help of advanced micro-abrasives and can be used for cut, polish and finish, depending on the buffing pads or materials used.