For the destructive cut-and-pull method of ASTM C1521, the inspector slices across the cured bead, runs a 3-inch cut down each bond line to free a tail, then grabs the tail and peels it back at 90 degrees. Good adhesion means the sealant tears cohesively or stretches past a set length before releasing. The tested spot is then resealed with the same material.
Field adhesion tests on the first drop all tore cohesively, so we're good to keep going with the same primer.
Seal a test length on each substrate on day one and pull it as soon as it cures, before a thousand feet of sealant go on with the wrong primer.
Also heard as
- pull test
- cut-and-pull test
- tab test
- adhesion pull
Related terms
Cohesive failure
A sealant tearing apart within itself while staying stuck to both joint faces.
Adhesive failure
A sealant pulling cleanly away from one joint face, leaving the substrate bare.
Primer
A thin liquid brushed or wiped onto a joint face or deck so the sealant or membrane bonds reliably.
Mock-up
A full-size sample of a wall, window or joint assembly built and tested before the real work starts.