We were having the bathroom decorated a little while ago and at the last minute I realised I needed to do something about the rusty plaster bead across the window. I chipped out some of the old plaster to expose the bead and treated it with KurRust. Once dry I repaired the edge with filler and rubbed it down when dry. I then gave it another coat of KurRust. I didn’t have time to coat the surface with anything else before the decorator arrived and you guessed it, there are now rust stains coming through.
What to do?
A) Do I repeat the process this time coating with an oil or shellac based primer before the emulsion.
B) leave it alone and just paint with stain block first then emulsion.
https://www.screwfix.com/p/zinsser-cove ... 1ltr/17114
C) Or chip out the bead and chuck it, rebuilding the edge with filler?
To be honest I always though fitting galvanised mild steel rust traps on plastered edges was a silly idea but this is actually the first time I’ve had this problem. Not too surprising really on a bathroom though.