Originally Posted by MariusGTV
I think the modern water based paints are to blame here. That and manufacturers habit of using light coloured primers under dark coloured top coats.
Technically, the standards required by the OEMs are the same whether it is paint supplied by Dupont, PPG, BASF or Akzo. They are also the same for both solvent and waterborne paint systems i.e. hardness tests, resistance to stone chips, resistance to chemicals/UV/Heat ageing etc etc are all conducted to the same levels with the same performacne requirements.
We don't use waterborne paints in our plant but the parts still have to conform to the same standards as other factories in our company who paint the same colours for the same customer using water based paints!
In practice there might be a difference in the length of time a clearcoat takes to fully cure but months down the line it should all perform the same. This can be as much down to the paint process as the paint itself.
Not sure why a light coloured primer would affect performance of the paint?
In my experience the use of a variety of coloured primers just allows the OEM paintshop flexibility to cope with painting a whole range of colours with differing film build & opacity requirements without having to compromise on the time it takes to paint the car! For example, an OEM in Coventry used to paint Tangerine Orange over a red primer because otherwise they couldn't apply the Basecoat colour thick enough in their standard production cycle to obtain a good colourmatch without having problems with paint runs, shading and the general quality of the finish.
Whites, reds and yellows are notoriously difficult because they usually require thick film builds in order to successfully cover the primer and get a good colourmatch. It is therefore not uncommon to paint Reds and Yellows, particularly, over a coloured primer so that a lower film build won't show as being patchy when the primer shows through! Bit of a cheat really!
So painting over a coloured primer will affect the colourmatch but shouldn't affect the functional performance of the paint system.
:Takes a deep breath smiley: