Wet-out
Wet-out turns up in 2 fields: adhesives, nonwovens. Here is what it means to the people in each one.
Wet-out in adhesives
How fully a tape's adhesive has flowed into contact with a surface, often visible through clear parts.
Good wet-out means the adhesive has filled the surface texture with no trapped air. Through glass or clear plastic it looks like a continuous dark, glossy area instead of a mottled, silvery one. Roller pressure, temperature, adhesive softness and dwell time all improve it. Poor wet-out cuts usable bond area and lets moisture travel under the tape.
"Wet-out looks patchy through the lens, roll it again with the hard roller and warm the part first."
Wet-out in nonwovens
Line and lab talk for how readily a fabric lets liquid soak in and spread instead of beading on top.
A hydrophilic topsheet or wipe base should wet out instantly, and a hydrophobic barrier layer should not wet out at all. Wet-out depends on the surfactant finish, the fiber and any contamination, and poor wet-out shows as beading, slow strike-through or patchy absorbency. Crews check it on the line with a quick drop test before lab results come back.
"Topsheet won't wet out on the drive side, the finish applicator must be starving that edge."