How many of you guys used sanding key to sand the primers and how many layers of primer did you paint and sand ?
This is what I prefer to use the most. It cost a little more but is very easy
to use and you can apply it as light or dark as you wish, also if any is left
behind on the surface it will not harm any top coats.
Layers of primer depend on quality of body work. In a professional shop our
body work is expected to be good enough that the prep shop does not have to
apply anymore than 2 coats of primer.........light block sand to remove light
sand scratches and orange peal from the primer.......then paint.
It is not for straightening panels....they should be "straight" before the primer
is applied.
To often people will use primer as body filler. Years ago the practice was
3 heavy coats of primer....Block sand.......3 more coats.....Block.....light coat
of primer ..... Paint. That's a lot of wasted primer ( and Money ) for improperly
finished Filler work.
The idea is to finish body work to P180.....then prime just enough to prep for paint.
Using the guide coat on primer sand just enough to remove any orange peal
and "very light" imperfections then top coat.
As A Note: The same holds true with Paint (base coat)....you only need enough to achieve
color build (or coverage), that's it, if 2qts does it there is no need to spray
a gallon of paint on the car........just wasting materials.