Rob Gypsum Joint Compound is a ready mixed putty designed to fill gypsum joint compound and skim coat for gypsum boards. It is intended for all stages of jointing plasterboard systems. It provides smooth, continuous, crack- resistant surfaces and is also suitable for repairing interior surfaces ready for priming and final decoration. Robson Gypsum Joint Compound can be used to fill in joints, hairline cracks, etc.