Hard / Soft Clear Coats:
Each vehicle assembly plant uses different clear coat paint from one of three major paint suppliers; PPG, DuPont, and BASF products and each of these companies have a range of several differing paints
1. Some vehicle manufacturers have more than one plant assembling the same model of a vehicle; each plant will often use a different supplier for the clear coat paints.
2. Each assembly plant may elect to use one of several OEM paints from PPG, DuPont or BASF clear coat product lines.
3. There are other factors that will have an effect; the composition of the clear coat used (single, duel component, or powder) this generally reflects the trade off the OEM is prepared to accept between scratch resistance and gloss level considered acceptable, oven drying time and its temperature, the relevant age (i.e. how long ago was the paint applied) spot panel repairs (refinish) that are carried out either at the assembly plant or the rail head or port of entry. This is also true of imports assembled in the US; usually one paint supplier is approved for all plants; however each plant may modify the application/bake process in order to meet production demand. This may also affect which has the harder or softer clear.
Diagnosis is the key, not guess work; before deciding on what products to use ascertain the paint surface conditions;
Paint thickness, New or Aged, Single stage or Clear coat, Oxidized, Soft or Hard or CeramiClear etc choose a panel and test your proposed foam pad / polish / machine speed process. Once you are satisfied that this process will give you the finish required, proceed to polish the rest of the paint surface. The more abrasive combination you have to use to see results, the harder the paint.
Using the least aggressive pad / polish combination followed, if necessary by an incrementally more aggressive approach until you find what works.
- Hard paint – does not mar as easily, but it’s more difficult to polish surface defects.
- Soft paint- is very easy to polish out surface defects, but easier to induce surface marring.
Hard and Soft Paints
Hardness: [In materials science, hardness is the characteristic of a solid material expressing its resistance to permanent deformation. There are three principal operational definitions of hardness: Scratch hardness, Indentation hardness, Rebound or dynamic hardness]
Hardness is defined as the ability of a material to resist local deformation (or penetration) from externally applied pressure, and is directly related to its tensile strength; stronger materials are generally harder. The enamel paint finishes on vehicles from the 50’s and 60’s era were as tough as porcelain. But rightly due to environmental concerns, those high percentage petroleum based paints have been generally superseded, resulting in the softer water-based paint finishes of today and the unavoidable orange-peel seen on many new and re-painted vehicles.
Today’s paints, unfortunately, rank somewhere near the bottom of the scale of hardness, especially single coat black / red paint the exception being white single stage and Ceramiclear, when compared to all the materials your paint can possibly come in contact with (always bear that in mind).
- An adaptation of that hardness scale( 1 – 10);
Talc = 1
Carbon Black [black paint pigmentation] = 2
Glass = 6
Titanium dioxide [white paint pigmentation] = 7
Hard and soft are relative terms; you can scratch the hard surface of a vehicles paint with a soft towel by the application of enough pressure. Both pressure and mechanical stress are defined as force per unit area. These two forces are the subject of Newton’s third law of motion; the law of reciprocal actions [To every action there is an equal and opposite reaction] Confused, how can a hard clear coat be so easily scratched? A force acts through a body that has a surface area; if the surface area is really small while maintaining an equal force, the pressure becomes astronomical and the object under pressure capable of penetrating the surface of an otherwise tough material. That’s why a micro fine thread in an otherwise soft towel will scratch your paint and the same reason a mosquito can penetrate a rhino hide with its proboscis (stinger). Note – Heat makes solids softer; cold makes them harder. Keep that in mind when detailing (especially polishing) your car in the sun or on a really, really hot day.