Heat-transfer vinyl is a thin coloured film with a heat-activated adhesive. The shape is cut from a sheet, the surplus is weeded away by hand, and the remainder is pressed onto the fabric with heat and pressure. What you end up with is a layer sitting on the cloth rather than in it.
It comes in matte, gloss, metallic, holographic and glitter finishes, and the crisp edge is its whole appeal — vinyl can hold a sharp serif or a clean number at a size no embroidery could manage.
Vinyl fails at the edges, and it fails from heat and flexing. The adhesive softens, a corner lifts, the lifted corner catches on something, and the lift spreads. Once a piece has started to peel it will not re-bond on its own.
Watch for:
Flex the vinyl gently between your fingers and watch the edges. Sound vinyl moves with the fabric; failing vinyl shows a hairline gap. A small lift on one corner can be re-pressed by someone who knows what they are doing, at moderate heat with a cover sheet. Cracking across the body of a shape cannot be fixed — it can only be replaced.
Where a garment carries a previous owner’s name or a studio’s number, factor removal into what it is worth to you. Vinyl can be lifted with heat and patience, but it often leaves a shadow on the fabric beneath.
Cold water, inside out, dry flat, never in a dryer. Never put an iron directly on vinyl — if you must press near it, use a cover sheet and work from the reverse. Do not fold a garment along a vinyl edge for storage; store it flat so the film is not creased. See Garment Care.