When sublimating glitter flake vinyl, it is important to remember that the vinyl has heat-activated adhesive on the back side, which is why the vinyl has to be pressed on the shirt first, and then sublimated as the final step. Doing sublimation onto glitter flake is best on black 100 percent cotton shirts, on which sublimation ink doesn’t show up. Even if the printed sublimation design goes well beyond the glitter flake transfer, it will be invisible to the eye. White cotton shirts will work too, but keep in mind the ink will transfer a small amount on the fibers, therefore the sublimation design needs to be trimmed down exactly to the shape of the vinyl transfer or should be incorporated somehow in the overall finished design if it goes beyond the edge. It will have a faded look on the fabric and will slowly wash out over time.
After cutting and weeding your heat transfer design with the glitter flake vinyl (the “white” color is usually best for transferring color), we suggest only tacking down the vinyl on the shirt at first for about 2 to 3 seconds at 320 degrees so that the total pressing time altogether is as short as possible. Over-pressing vinyl mostly results in brittle vinyl that is prone to cracking easier and can affect the adhesive, but so far we haven’t seen any issues with this decoration process. Then, lay the printed sublimation transfer paper face down onto the vinyl and press at 380 degrees for 45 seconds.
-Kalina Mondzholovska, Coastal Business Supplies