I have been doing a lot of plaster patching on my old 1920s era house. The basic approach here is the holes were filled with blueboard, then we used 2 coat base and finish plaster (USG diamond). I painted the edges of the old surface with Plasterweld so we could feather the patch out over the old wall to blend it. Now at most of the transitions there is a mix of plaster and Plasterweld. What I can't seem to find from the manufacturer is if I need to do anything to the Plasterweld surface before painting? I could try to scrape it, sand it, prime it or just paint it. What is the correct approach?
Here you can see the feathering and the pink plasterweld. I was conservative and gave myself plenty of room to feather.