Bonding primers range from solvent solutions that let cyanoacrylates bond polyolefins, to glass and paint primers for windshield urethanes, to corrosion-inhibiting primers that lock in a fresh aerospace aluminum surface until bonding. They are applied very thin, usually wiped or sprayed, and given a set flash time. Too thick a primer layer becomes the weak link and fails cohesively.
Primer has to flash ten minutes before the urethane bead goes on, don't rush the glass.
Primer only works at the thickness on the data sheet; a heavy, wet coat becomes a weak layer of its own.
Also heard as
- bonding primer
- surface primer
Do not mix it up with
- Activator: An activator speeds the cure of the adhesive; a primer prepares the surface so the adhesive can stick.
Related terms
Adhesion promoter
A chemical, often a silane, that links an adhesive to a surface by bonding to both.
Activator
A liquid applied to one surface to speed or start the cure of an adhesive placed on the other.
LSE
Low surface energy, describing plastics and coatings that most adhesives cannot wet or bond without help.
IPA wipe
Cleaning a bonding surface with isopropyl alcohol on a lint-free wipe just before adhesive goes on.