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GT-782 Cookbook: Advanced Menu
How to pretreat 50/50 shirt




********* Take Your Time and Energy to Print on the GT-782 *********

Pretreatment is inevitable for white ink. Print quality depends on pretreatment,but there is a very big difference in pretreatment on different types of garments and we have to control it.

There is a reason why 50/50 garments print poorly. On the average, cotton-polyester mixed garments are thinner than 100% cotton garments. Polyester fiber does not absorb water. Its surface is flat and smooth and there is no place to hold the Pretreatment and the white ink on the surface.
There still is a way to print on cotton polyester garments. Indeed it takes your time and energy, but it works. There is another advantage: the less amount of Pretreatment, the less drop of heat press temperature.

The volume of layers depends on the brand. From our experience, Fruit of the Loom 50/50 black is OK with two layers, Hanes 50/50 black needs three layers, Gildan 50/50 black needs four layers. Check if the surface is glossy, lay flat, like you pretreat on cotton material. Test before you print.

How to print good
Apply 1/3 amount of Pretreatment.
Cure with heat press, with high pressure (same as cotton garment).

First thin layer is made on the surface.

Apply 1/3 amount of Pretreatment.
Cure with heat press, with high pressure.

Second layer is made on the first layer.

Apply 1/3 amount of Pretreatment.
Cure with heat press, with high pressure.

Perfect layer is made.

Print data with maximum white ink: Mask White=5, Highlight White=2-3.




The reason why 50/50 garments are printed poorly
Let us explain how pretreatment works on garment step by step:

Remember that cured Pretreatment makes a thin film (the blue line in the above image) to prevent the white ink from sinking into the fiber. Compare the two images below; because the differences of materials and thickness causes difference in holding the Pretreatment.

--- 100% cotton garment ------ 50/50 garment ---


The capacity to hold pretreatment is different in different garments. As a result, cotton / polyester garments cannot hold enough Pretreatment, because of these differences, cured "Pretreatment film" by the heat press is not as well-produced on cotton / polyester garments compared to the 100% cotton garment.



Finally the print result will be as follows: White ink is stopped on solid pretreatment film and covers the surface on cotton garment. On the other hand white ink goes through the thin and weak Pretreatment film on cotton / polyester garment.


Now you can see what is wrong with the cotton / polyester garment and what should be done for it --- there is another way to success. It takes time and energy, but it can be done.

The key to this is to make a pretreatment film on the surface: pretreat a little, cure, and then repeat this to make a thin layer on the surface.

This "divide and rule" process is available even for 100% cotton garments, especially black T-shirts, which is necessary for whiter white.



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