We have some pinhole leaks in an old fire sprinkler system in a large apartment block. Is there an adhesive that will seal those leaks?

Polytetrafluoroethylene (PTFE) is low-surface-energy plastic that is very difficult to bond. PTFE exclusively comprises fluorine and carbon atoms with no polar atoms such as oxygen or nitrogen.

What does fumed silica do for adhesives and sealants compared to other thickeners like wood flour or clays, and how do you handle the huge clouds of dust from the bags?

I see references to fixture time on adhesives technical data sheets. What exactly does that mean?