Abstract: A two component polyurethane coating system is disclosed in which the pot life is extended while retaining rapid cure. The system employs a first component which is a solution of a soluble resin containing active hydrogen atoms capable of reacting with isocyanate functionality, and said first component has dispersed therein an amine catalyst for the reaction absorbed in a molecular sieve having a pore size large enough to absorb the amine catalyst. The molecular sieve minimizes the catalytic effect of the amine catalyst when the two components are mixed until after the absorption of atmospheric moisture forces the sieve to release the catalyst to speed the cure. The second component comprises a solution of an organic polyisocyanate, this solution containing an organotin accelerator which has been deactivated with acetic acid or formic acid which minimizes the accelerating effect of the accelerator when the two components are mixed until after vaporization of the acid frees the accelerator to speed the cure.