"nightjar .uk.com" nightjar@insert my surname here wrote in
message ...

"JoeJoe" wrote in message
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What is the difference between a primer and an undercoat?

Traditional painting uses a three coat system: primer, to prepare an
unpainted surface to receive paint; undercoat, to build up the
colour; and
top coat, to provide protection to the whole. Modern paints tend to
be one
coat paints, which achieve colour build and protection in the same
paint.


Err not IME, totally wrong about one coat paint, you still need to use
undercoat (if not primer) were the surface has not been painted before
or the paint has been removed, 'one coat' paint is for final top coat
/ *re-finishing*.