Tensile tests showed good correlation with the cracking on a severe weathering test, but there were some anomalies. The authors propose as an alternative a short severe weathering test in comparison with primers of known performance. 48 commercial products were tested and the weathering of primers alone on wood showed bad failures; even with topcoats the worst primers showed failure in 3 months, a few were as good as British Standard lead-based primer for wood. Pretreatment of the wood with a resinous water repellent preservative impboved the performance of the worst primers but had little effect on the performance of the better ones. Bend tests and vapor permeability measurements were not as successful in predicting durability as the tensile strength measurements. -- AATA