How do you know if the material has cured properly?

The main indicator of a proper cure is to measure the hardness of the repair.  NRI recommends using the Shore D hardness, and we have verified through testing that the resin will typically attain around 80% of it's ultimate hardness after 24 hours, and up to 90% after 48 hours.  There are several environmental factors that affect cure rate, and NRI's Engineering Department should be contacted to verify specific factors for your repair. /L