|Posted on October 8, 2012 at 3:50 PM|
OEM clear coat is approximately 1.5- 2 mils (35- 50 microns) thick. For comparison, a sheet of printer paper is approximtely 2.7 mils (70 microns) thick. That means the clear coat on your car is about as thick as printer paper, if not thinner. Total paint thickness of OEM clear coated paintwork typically reads between 4- 7 mils (100- 180 microns). The following are the maximum allowable clearcoat reductions the major USA car manufacturers will allow: Chrystler- .5 mils (12 microns), Ford- .3 mils (7 microns), GM- .5 mils (12 microns).
Depending on the model, a car has a surface of 15 to 25 square meters that needs to be coated. A total of 12 to 15 liters of paint are needed for this job. The coating is a mere 100 to 110 micrometers thick, thus around one-tenth of a millimeter. This is comparable to the diameter of human hair (about 100 micrometers).
Cathodic electrocoat (e-coat):
After the areas have been pretreated with zinc phosphate, first the e-coat is applied. To this end, the body is dipped in a bath with a waterborne dispersion (consisting of cross-linking agents and binders) for approximately three to five minutes. Then a direct voltage of 250 to 500 volts is applied to the body and a counter electrode located in the bath. Electrically charged paint particles are deposited on the body and form an approximately 20 micrometer thick coat there. Its primary job is to provide corrosion protection.
In the next step, the primer is applied. This approximately 30 micrometer thick polymer coat (often polyester or polyurethane) smoothes out small surface irregularities. For this reason, it contains inorganic fillers like kaolin, chalk or talcum. In addition, it improves adhesiveness and corrosion protection. Because this layer is particularly elastic, it prevents the paint from flaking off when it is exposed to stone chipping, since it absorbs and redirects the energy of the impact.
Now the basecoat is applied. This layer is also a plastic and usuallyconsists of polyurethane. With a mere 15 micrometer film thickness, however, it contains the key elements determining the appearance of the vehicle: color and effect pigmentsknown as metallic or pearl effects, whose elegant effect many car aficionados especially value.
The single- or multi-component clearcoat applied in the final step is what creates the very tough and glossy protective layer. The job of this approximately 40 micrometer thick coat is to protect the finish from a variety of environmental influences. They include sun, rain, snow and temperature fluctuations, as well as air pollutants, road salt, sap and bird droppings, along with mechanical wear.