Glossary · Material

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Flex film (HTV)

A film for ironing onto textiles. A cutting plotter cuts out the design, which is then pressed onto the fabric with heat.

Explained in more detail

Flex film, known in English as heat transfer vinyl (HTV), consists of polyurethane or PVC, is typically 20 to 100 µm thick and has a hot-melt adhesive on the back and a transparent carrier film on top. The plotter cuts only the colour layer, not the carrier. The excess material is then weeded and the design is applied with a heat press or iron; for Siser EasyWeed, 150 °C for 10 to 15 seconds is specified. Each colour is a separate film layer, so photos and colour gradients are not possible. Besides smooth flex film, there are flock, glitter and metallic films.

Where does the term come from?

Flex describes the flexibility of the film, which moves with the fabric. In English it is called heat transfer vinyl, that is, vinyl for transfer with heat, even though many types are made of polyurethane.

In practice

• Mirror the design before cutting: the film lies on the mat with the glossy carrier side down.
• Pre-press the fabric for 5 to 10 seconds beforehand; this smooths out creases and drives out moisture.
• Whether you peel hot or cold is stated on the film's packaging.
• Cricut recommends washing only after at least 24 hours, inside out and without bleach.

Not to be confused

Flex film is not plotter film for stickers: vinyl for windows and stickers adheres without heat and is not mirrored. Flex film needs heat and is intended for textiles.

Frequently asked questions

Do I have to mirror flex film?

Yes. It lies carrier side down when cutting and turns over when pressed on. Vinyl for stickers, by contrast, is not mirrored.

Does flex film last on cotton?

Yes, flex film adheres to cotton, polyester and blended fabrics, including dark fabrics. If pressed poorly, it can crack or come off over time.