I used some of this to fix a fuel leak on an old farm truck that we use around the property. It was used to seal a leak at the fuel inlet to the carburetor. The fitting is so old that it never even tightened up upon reassembly, so some good ole hardening goop seemed like an easy fix. http://www.neverseezproducts.com/gasketseal.htm When I went to use the truck the fitting started to leak again. When I pulled it apart, I found that the goop was nothing but a fine yellow powder. As a kid and young adult I did plenty of mechanical work, esp rebuilding dirt bikes, and gasket goop was standard item, but I never saw it do this before. At this point there was nothing to lose, and some JB Weld did the trick just fine [put in an in-line filter to replace the one internal to the carb], but I don't understand what happened to my goop! Has anyone else ever seen this?