Cotton-poly blends press like cotton — until the poly content climbs. On dark, high-poly blends, treat them more like polyester.
The number on your press is a suggestion. Presses ship miscalibrated, read differently across the platen, and drift over time — the panel can say 280°F while the print only sees 240°F. What actually bonds a transfer is the print reaching 280°F for 3–5 seconds at firm pressure. So you may need to set your press higher — often 300–310°F — to get there. Dial in your press once, then trust it.
Presses read differently and drift — it's not uncommon for even new heat presses to be off by 20% or more. Answer a few quick questions and we'll get you a good starting point to dial in from.
A 2–3 second tap flattens the garment and drives off any moisture. Our film no longer needs it to bond — but a flat, dry surface still gives the most even contact, so it's worth it in humidity or on a garment that's been sitting.
280°F · 3–5 sec · firm 90 psi. Heat and pressure settle the TPU into the fibers. Hit the number and lift.
Cover the design with a textured sheet and press again. It seats the adhesive deeper for wash durability and gives a softer, matte hand feel. Skip it only for rush or throwaway merch.
| Feel | Pneumatic (psi) | Manual dial (1–9) | What it looks like |
|---|---|---|---|
| Light | 20–40 | 1–3 | Paper slides out easily |
| Medium | 30–50 | 4–5 | Paper drags a little |
| Medium-firm | 40–60 | 5–6 | Firm tug to pull paper |
| Our spec — firm | 90 | 7–9 | Paper won't budge |
On a pneumatic press, set the gauge to 90 psi. On a manual clamshell, aim for a solid two-finger effort to latch, then confirm with the paper-drag test.
Closes at a slight angle, so thick seams take more force at the hinge. Great for flat tees — just latch fully for even contact.
The platen comes straight down for the most even pressure. Best on thick goods like hoodies, denim, and canvas.
Air holds identical pressure every cycle — set 90 psi once and every press matches. Ideal for volume.
Light-colored blends take the standard cotton setting — 280°F, 3–5 seconds, firm.
Dark or high-poly blends can migrate: lean toward the polyester approach (cooler, shorter) and test.
Tri-blends are thin — don't over-press. Firm but not crushing pressure keeps them from glazing.
A textured cover sheet on the post-press gives blends a softer hand feel.
| Symptom | Likely cause | Fix | |
|---|---|---|---|
| Faint halo on a dark blend | Partial dye migration from the polyester content | Lower the temp toward the polyester range and test | Finish |
| Press mark or glaze on a thin tri-blend | Too much heat or pressure for a lightweight knit | Ease the pressure and use a textured cover sheet | Finish |
Only in proportion to their polyester content. A light 50/50 is usually fine at the standard setting; a dark 65/35 behaves more like polyester and wants the cooler, test-first approach.
They're thinner and more heat-sensitive, so use firm-not-crushing pressure and a cover sheet, and test if the garment is dark.
Upload a design and our preflight scores how it'll press on blends — ink density, hand feel, and adhesion, before you order.
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