The industrial process of pulling a knitted synthetic garment, typically hosiery or socks, over a heated metal leg form to set its permanent shape. This thermal memory step occurs before dyeing and finishing. Preboarding prevents the fabric from shrinking, twisting, or wrinkling during the high temperatures of the dye bath.
Heard on the job
If you don't preboard these nylon stockings properly, they'll come out of the dye vat looking like twisted ropes.