Answer: calks

AnswerCrossword Clue
CALKS

Does some sealing (var.)

CALKS

Makes tight against leakage.

CALKS

Stops up crevices.

CALKS
Stops up (cracks).
CALKS
Uses oakum.
CALKSHorseshoe cleats
CALKSHorseshoe parts
CALKSGrippers on horseshoes
CALKSRepairs, in a way: Var.
CALKSPlugs air leaks