A gummy bond usually means off-ratio mixing, poor mixing, an expired lot, cold temperature or, for moisture-cure products, too little humidity. Sometimes heat finishes the cure; often the joint has to be cleaned out and redone. Technicians press a thumbnail into the squeeze-out to check before load testing.
Squeeze-out is still gummy on the back side, I think the hardener barrel ran short.
Also heard as
- undercured
- soft
Related terms
Off-ratio
Describing a two-part adhesive dispensed with the wrong proportion of resin to hardener.
Marbling
Swirls and streaks of separate colors in a two-part adhesive that show it has not mixed thoroughly.
Cure
The chemical reaction or physical change that turns a liquid adhesive into a solid that carries load.
Mix ratio
The proportion of resin to hardener in a two-part adhesive, given by volume or by weight.