Acrylic, UV-acrylate and anaerobic adhesives cure through free radicals that oxygen scavenges. A thin surface layer exposed to air may stay tacky even when the bondline is fully cured, and anaerobics stay liquid wherever air reaches them, such as squeeze-out. Higher lamp intensity, specific wavelengths, nitrogen blanketing or surface-cure formulas reduce the effect.
Fillet's tacky on top but solid underneath, that's oxygen inhibition, more lamp power or a longer dose.
Also heard as
- air inhibition
Related terms
UV-cure adhesive
An adhesive that cures in seconds when exposed to ultraviolet or visible light of the right wavelength.
Anaerobic adhesive
A one-part liquid that stays fluid in air but cures when sealed between metal surfaces away from oxygen.
Squeeze-out
The excess adhesive that oozes out along the joint edges at clamp-up, read as proof the joint is full.
Fillet
The bead of adhesive left around the edge of a joint, which smooths stress at the ends of the bond.