Category: Stretching

Knit Loop Physics: How to Enlarge Fleece Safely

Sweatshirts and hoodies utilize circular knitting machines that create interlocking loops of yarn rather than perpendicular warp-and-weft grids. This structural loop architecture makes knit fleece inherently elastic. When dry, pulling on cotton fibers risks yarn snapping and rib cuff warping. However, when cotton is treated with warm water and a cationic surfactant (hair conditioner), the lubricating agent coats the cellulose chains, allowing the looped coils to slide past each other under outward tension. By pinning or weighting the garment until completely dry, the newly expanded yarn geometry is locked into place.