"RichK" wrote in message
...

Have a case of peeling paint on the door frame. Looks fine, but if you
scrape it, even with a finger nail, it comes off quite easily. Was
painted
before my time. There's a layer of paint, under the one that's peeling.

Suspect it's a case of latex on oil, without a primer. Removing the top
layer would be a mess. If I primed the top layer with say Kilz (or
similar), would the primer penetrate the latex and attach itself to the
layer below?

1. No, new primer is not likely to penetrate the
old colour coat and adhere to the old primer which
you do not know for sure to be there.

2. Your questiion is framed as if you were sure the
old colour coat flakes off leaving the old primer safely
adhering. This seems unlikely, unless both (2a) the
old primer was correctly applied and (2b) the old colour
coat was improperly applied (e.g. surface not washed
and sanded beforehand.)

You must decide between:
Method A = thorough preparation (scraping or blowtorch
to remove loose paint, then filling and sanding to prepare
a good surface; then quality paint, both primer and colour
coat.
Method B = touching up, perhaps in spots, while knowing
that if you guessed wrong in any one respect you will
have to go to Method A later.

--
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)