You must be very careful when heat pressing 100% polyester tees and uniforms. If the press is too hot or the pressure too high, you are likely to leave glossy areas on the fabric. You may also experience indented lines on the shirt where the edges of the transfer paper or heat press material meet the fabric. The best option to avoid all of this is to use kraft paper as a cover sheet and limit the time and temperature as much as possible. Heat press material such as Siser Easyweed is applied at a lower temperature than most. Also, new cold peel ink transfers can often press at much lower temperatures.
When you decide on a specific heat press material that you want to work with, it is important to keep in mind that many materials will not work when they are layered in two or more color designs. Also, if the material is a cold peel, you will be forced to wait for long periods before heat pressing the second (and sometimes third) color. This is why I recommend the Siser Easyweed for two and more color designs. The Easyweed is pressed at a low temperature (305F) and peeled hot. Even more important, you can heat press the first color for only 2 seconds before peeling and pressing a second color. This speeds up the entire heat press process. Other benefits in heat pressing material this way include less shrinking of the fabric and protecting the fabric from color changing and other damage.
When cut properly, heat press material should not be difficult to weed. Numerous factors are involved including blade depth, force, speed, blade sharpness, and many more. If you follow each of these steps, weeding will be much easier and faster every time. First, make sure the blade depth is correct. The blade should only stick out of the blade holder far enough to cut the film and scratch the surface of the clear carrier. Test this by taking the blade holder out of the machine and cutting a circle in the heat press material using your hand. If the blade cuts through the material and the carrier, it is out too far. From here, put the blade holder back in the machine and adjust the force. This is where the test button on the cutter will help you. Test every 20 grams of force and see which force weeds the test cut the best. Once the blade depth and force are properly set, check the speed setting. You can cut fast with films such as Siser Easyweed. When it comes to glitters, metallic, and reflective, a slower speed is recommended. I have some other general troubleshooting to offer in regards to cutting. If the heat press material is cut but the cut lines look more like tear lines, check the cutter protection strip. If this is damaged, replace it and your cutting lines will be much cleaner. If it looks ok, check the blade. Perhaps it is dull and needs replacing. Finally, if all else fails, put a drop of oil in the blade holder. The blade may not be spinning freely. When it is not facing the correct direction, the cuts are typically very jagged.
A common problem when heat pressing uniforms is applying even pressure to the print. For instance, when a player’s name is a few inches below the neck, the neck can cause the pressure to read much higher than what it is. Additionally, this can cause discoloration on the neck itself due to the higher heat and pressure. Try utilizing a heat press pillow inside the t-shirt or uniform. This will allow for the neck to sink down into the pillow and give more pressure to the print itself. Now your print will wash better and the shirt will have no heat press marks.