Six months ago I removed deck hardware I bedded with Boatlife in 1986. It was plyable and stuck to the glass like glue. The material was definitely hardening from age but not even close to brittle. Before Boatlife I used commercial window cauking which was a high grade two part polysulfide mix...the stuff has been around for a long time. Tip on Boatlife...spritz it with water to start the curing process to get the surface through the tacky period quickly. This will keep the bead from gathering dirt. It doesn't hurt the application. Bill P.