Thank you for enquiring. Builder’s Bog does not go “rock hard”. That would be far too hard for a timber repair and impossible to pare and sand down level.If you can indent the repair with your fingernail, as you can do to pine timber, but not actually dig it out with your nail, it will be hard enough to paint. But if too soft due to lack of hardener, the only recourse is to dig it out and try again. The colour should be a medium pink before sanding and lighter when freshly sanded and powdery, returning to medium pink when wetted.

It will not eventually cure properly if too little or too much red hardener is used I am afraid.

Regards
Stuart Jordan
Managing Director
Chemical Specialties Ltd.
17.5.2016