Mr. Willis, As far as I know, from my dealings as vice-chair of the Solder Mask Task Group, no such reliable test method exists. You might look for a method which examines the change in capacitance with curing time. I saw a demonstration of it a few years ago, but never had the opportunity to pursue the science. The basic theory is that an uncured solder mask is applied over a test pattern and the resistivity and capacitance are measured as the cure cycle goes along. When you have reached a point at which the two values are only nominally changing, you have reached full cure. I wish I could be of more help. I guess memory is the first thing to go. Doug Pauls aka [log in to unmask] Contamination Studies Laboratories.