[redmt]

When I first started building engines in the late 60's and 70's I don't remember having silicone to use (fuzzy memory). When it became popular, you'd find it in radiators, pick up screens and filters. There would be blue strings of snot everywhere.

Cat has two products I swear by. There is a non hardening and a hardening that I use exclusively along with aviation Permatex sparingly. I think if you tried them , you'd throw away any tubes of RTV/silicone you have left. If you don't have a Cat dealer nearby, I'd be happy to send you a tube of each.