In our bathroom there's a 4" x 12" section of paint, on the wall up against the ceiling that's peeling. I observed that the top layer of what's peeling is the existing yellow paint, then it appears there's a 1/32nd layer of THIN plaster, then two more very thin layers of paint. This pulled back from the hard plaster on the wall.

I'm sure I could scrap away these 4 layers all over the bathroom, but that seems like way too much work for other sections that are completely intact.

I'm wondering how you would repair this section? We're painting over the existing yellow paint with white - so maybe priming everywhere with a thick primer would effectively fill in this flat section? Or would it be better to repair the peeling section with some kind of skim coating, then prime with a regular primer?

Any ideas? Thanks

Once set they do not soften again from moisture (unlike the premixed stuff that can be softened forever).

Eucoweld is a good brand, but if you cannot find it use Elmer's white glue cut 50% with water.

paint over the area that will be covered and allow it to go tacky before applying compound.