For maximum corrosion resistance this primer with its high zinc content will provide cathodic protection on shot blasted steel. An alternative to the conventional hardener is a hardener that provides better hold-out when heavy applications are made on vertical services. With either hardener, the dried film contains 92% by weight of zinc (approximately 64% by volume): it conforms to BS 4652 Type 3, which is specified by the Department of the Environment for structural steelwork priming.