Heat press settings Celsius for UK crafters

Fabric

Poly-cotton blends

A 50/50 or 65/35 shirt is not halfway between two crafts. Vinyl makers list blends on the cotton row. Sublimation only dyes the polyester half.

Check the label before you pick a method. “Cotton rich” can be anything from a touch of polyester to a 65% polyester workwear shirt. The vinyl charts care that a blend is listed. The sublimation chemistry cares about the polyester share, and these sources do not print a minimum percentage.

HTV

Siser EasyWeed lists poly/cotton blends with cotton and polyester: 150°C (305°F), 10–15 seconds, medium, hot or cold peel. Garment Films’ chart includes mixtures of polyester and cotton on the same product rows as cotton, and it tells you to test. Use the standard, glitter or flock page for the film you have.

The polyester in the blend can still migrate into white or pale vinyl, especially if the shirt was dyed with disperse dyes or was itself sublimated. If a pale film shifts colour, treat it as polyester dye migration and look at a blocker, rather than pressing hotter.

DTF and sublimation

DTF is the full-colour method these UK guides actually name for blends. Xpres list cotton, polyester and blends together, with press examples from 150–160°C and a separate Garment Films FAQ range of 140–150°C.

Sublimation on a blend is a compromise. You can use the polyester time and temperature on a high-polyester shirt sold for the process, and you should expect a lighter result than on 100% polyester. A cotton-rich blend is the wrong blank. Buy a polyester shirt instead of fighting the chemistry.

Common questions

Should I average the cotton and polyester temperatures?

No. The HTV charts already include blends at the cotton figure. Inventing a midpoint is less accurate than following the film.

Why does sublimation look speckled on a blend?

Cotton fibres do not take the dye. Xpres say sublimation will not work on cotton. In a blend, only the polyester portion colours, so the print looks light or heathered.

Sources