Flex or flock — the question comes up on every club order. Both are applied with heat, both last years, both come in every colour. The difference is settled by three questions.
Question 1: how fine is the motif?
Flex is a thin, smooth polyurethane film. It reproduces fine contours, narrow letters and thin lines down to about 3 mm stroke width.
Flock carries short upright fibres — velvety, visibly raised. Those very fibres eat the detail: below about 5 mm stroke width the contour blurs. A delicate crest belongs in flex; a bold shirt number may be flock.
Question 2: how should it feel?
Flex lies flat and is barely noticeable when worn. On a sports shirt that is the advantage — nothing scratches, nothing traps heat.
Flock feels velvety and is clearly perceptible. That is the classic club-shirt impression, which reads as more premium — lovely on a sweatshirt or a training jacket, rather unpleasant on a thin performance shirt.
Question 3: how will it be washed?
Both take domestic washing well, inside out and without fabric softener. Flex typically survives 50 washes at 40 degrees, flock about 40. Anyone washing hotter or more often — hospitality, care, trades — is better served by embroidery: polyester thread is boil-proof.
The special cases
- Dark polyester (most sports shirts) needs a blocker film, otherwise the fabric dye bleeds through and white turns pink after a few washes.
- Nylon and rain jackets do not take the usual press temperature — there is a special film for that.
- Glitter and metallic are flex variants with an effect, but more delicate: 30 washes at 30 degrees.
- Reflective exists in both families — sensible on running and work wear.
And if neither fits?
With photographs, gradients and more than four colours film is the wrong route — it becomes handwork layer by layer and costs more than printing. We say so beforehand instead of producing a run that pleases nobody.
The full film list with durability, substrate and wash figures is on the plotting page.