RUST ON WINDOW-SILL

[toejoe]

Hi
This problem relates to rust appearing on a painted window-sill .The rust is as a result of the renforcing metal in the sill, hairline cracks in the sill and moisture. How can I SOLVE THIS PROBLEM? I have tried several methods
ISOPON, ALUMINIUM FOIL ,ROOF SEALENT,NONE OF THEM WORK.I do not want to have to replace the sill.

 

[Nige F]

sure it`s a cill not a lintel Zinsser primer.....maybe