Tri-Coat or 3 stage is 3 coats of finish as opposed to Base-Coat or 2 stage which is simply 2 coats of finish product. At this time most automobile OEM Tri-Coat consists of a solid white base, which is specified in the color code, some number of coats of pearl, and clear coat. There are a few red base colors followed by pearl and clear too. I say at this time because car color trends, like fashion, change from year to year. The vehicle paint code will tell us exactly what the base and pearl colors are.
Preparation up to the base coat is the same for tri-coat as for base-coat. In order to achieve an invisible color match most professionals would plan on blending the tri-coat or perhaps spraying the whole side of the car. A perfect panel to panel color match would be considered unlikely. Since I could not make such a repair with aerosols I will discourage you from attempting it.
If, however, you want to paint a rear view mirror or a valance between a grill and chrome bumper, or a door jamb, you could do fine with aerosols.
Spray the base color to hiding. Allow to flash. Spray one light coat of pearl. Compare the pearl you just applied to the saturation of pearl in the OEM finish. The trick to a color match is to only put on as much pearl as is needed to reach the look of the original finish. In a professional situation the painter would create a let down panel which is a big test card sprayed with the base and then 5 sections with 1 thru 5 coats of pearl all clearcoated. The idea is to compare this to the vehicle to determine how many coats of pearl it will take to get the color match.
After the pearl is sprayed allow to flash and clearcoat.
For purposes of ordering, whatever amount of base is needed, plan on 25% that amount of pearl, or less. Most pearls will match with 1 to 2 coats just dusted on.
Tri-coats are also popular in custom paint work and motorcycles. Gold and silver bases have been around for years in those applications. Usually there are no color codes in those situations so color matches are near impossible.
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