Products for surface preparation, such as primer and activator, are intended to improve the adhesion of the adhesive to the bonded surface. They are applied before applying the glue.
Why use Loctite activators and primers?
Some materials have low surface energy (e.g. Teflon PTFE). In order for the adhesive to achieve good adhesion to such a substrate, its surface energy should be increased - and wettability should be improved. One of the ways is to use a primer.
On the other hand, Loctite activators are used to initiate or accelerate the hardening reaction of the adhesive. They also allow the excess glue to harden. For some adhesives, the use of an activator is necessary for the adhesive to cure.
Which Loctite activator or primer to choose?
When joining difficult-to-bond plastics with instant adhesives, we recommend the Loctite SF 770 activator. It is applied before bonding.
Loctite SF 7455 is a general purpose cyanoacrylate activator for all substrates, we apply it after gluing - it accelerates the curing of the glue.