Epoxies, acrylics, urethanes and silicones fill gaps of a millimeter or more and cure through them. Standard cyanoacrylates and anaerobics need close fits, often under about 0.1 to 0.25 mm, and cure slowly or not at all in wide gaps. Gap-filling grades are thicker and sometimes need activators. Gap tolerance decides which chemistry suits real-world parts with sloppy tolerances.
Fit on these castings is a millimeter in places, so forget the CA, we need something with real gap filling.
Also heard as
- gap fill
- gap-filling ability
Related terms
Cyanoacrylate
A one-part instant adhesive that cures in seconds when trace moisture on a surface triggers it.
Anaerobic adhesive
A one-part liquid that stays fluid in air but cures when sealed between metal surfaces away from oxygen.
Bondline
The layer of adhesive between two bonded parts, and in shop talk the thickness of that layer.
Spacer beads
Small glass or plastic spheres mixed into an adhesive to hold a set bondline thickness under clamp pressure.