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

"JoeJoe" wrote in message
...
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*.

The statement that one coat achieves colour build and protection in the same
paint means that it replaces both the undercoat and the top coat used in
traditional systems. Primer will still be required if the base material is
unpainted. You should not use undercoat as the base coat on an unpainted
surface and you shouldn't need it over primer if you are using a one coat
paint.

Colin Bignell