If you customise polyester t-shirts or sweatshirts through sublimation, you have probably encountered this problem: when lifting the press, marks appear around the outline of the paper. These are permanent marks that should not be present on a final product intended for a customer.

In this post, we explain why they occur and share with you a very simple trick that works better than traditional solutions.

Why do ironing marks appear in sublimation?

During the sublimation process, temperature and pressure are applied directly to the polyester. This fibre is heat-sensitive, and if the edge of the paper is well-defined, the fabric may be permanently marked. Sometimes the marks fade after the first wash, but they do not completely disappear.

What traditional solutions have been tested?

Before the trick we share below, the most commonly used solutions were:

• Place a sheet of protective paper or a thin cloth between the iron and the garment to reduce direct pressure.
• Use a Teflon pad on the lower base of the iron to soften the contact.

Both help, but they do not completely eliminate the problem.

The ultimate trick: tearing the edges of the paper

The technique involves tearing the 4 edges of the sublimation paper by hand, just before placing it on the garment.

Why does it work? Tearing the edges creates a smoother transition between the paper and the fabric, avoiding a straight line that defines the outline. Heat and pressure are distributed more gradually.

How to apply this trick step by step?

1. Print your design on sublimation paper, leaving a margin around the design (at least 1 cm on each side).
2. Tear all 4 edges of the paper by hand, avoiding a straight or guillotine-cut line.
3. Place the paper on the garment, as you normally would.
4. Iron at 200°C for 45 seconds with medium pressure.
5. Remove the paper and inspect the garment: there should be no marks around the edges.

Frequently Asked Questions

Can I tear the paper with a guillotine or scissors? No. A clean cut leaves a defined edge that marks the fabric. It is essential to tear it by hand so that the edge remains irregular and without marked pressure.

Does it work on all types of fabrics? It works very well on 100% polyester fabrics, especially the smoother ones. On pique or micro-perforated polyester (like sports jerseys), the result also improves, although slight marks may remain if the pressure is too high.

What if the design reaches the edge of the paper? You will need to leave a white margin for tearing. If your design is full bleed, it is ideal to print on a larger paper and then tear the edges.

Can I use this trick for sublimation on rigid materials? No. This trick is only for fabrics. On hard substrates like mugs, plaques, or keychains, there is no risk of edge marks from the paper.

Is it suitable for high-weight sublimation papers? Yes, but the thicker the paper, the harder it is to tear it precisely. Some professionals use a damp sponge to slightly soften the edges before tearing.

Ironing marks in sublimation are a common yet avoidable issue. By using this trick of tearing the edges of the paper, you can significantly improve the final result and offer a professional product without visible marks.

If you have any questions, share them with us in the comments. Our team will be delighted to provide you with answers and assistance. You can also contact our Customer Service department directly for additional help.

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