Like Steve and Rebecca, I cannot recommend ordinary dyes for use on polyester. If you are happy with the pastel effects obtained by using cotton dyes to dye just the cotton fibers in a 50% cotton blend, they can look nice and last a long time (once all unattached dye has washed out), but the pastel look is rarely a tie-dyer's goal, and if there is any sort of fabric treatment that was applied in manufacture, it is apt to cause splotches, streaks, and even paler colors. PFD ('prepared for dyeing') fabrics or garments made of cotton, rayon, or silk are the best for tie-dyeing.
What I would recommend for polyester shirts would be to get
one shirt and do some tests on it, first. Do not use ordinary fabric dyes, since polyester will not bond to them, no matter what chemicals you use with them. Many common fabric treatments, such as permanent press or stain-resistant finishes, will prevent even the right kinds of dyes or fabric paints from working correctly. I have a suspicion that wicking-type finishes might not be a problem, but I do not know. It would be pretty awful to get an entire team's worth of shirts and then find that you can't do a thing with them.
On your polyester test shirt, you can try either special polyester dyes, or
fabric paints that are recommended for use on polyester. In your testing, try some Crayola
fabric crayons (you can often get these at Joann's fabric store or even Walmart)—do not confuse these with children's ordinary wax crayons!—to make iron ons, or buy some
Dye-na-flow fabric paint and use that for tie-dyeing (well, really, tie-
painting, since no dyes are involved). All of the Jacquard brand fabric paints are supposed to work pretty well on polyester, and Jacquard 's Dye-na-flow paint moves on the fabric somewhat like dyes do. Other brands of fabric paint may work, as well, but, in any case, be careful to run a small-scale test first, whatever you do. The binders used in some fabric paints do not stick as well to synthetics as they do to natural fibers (I learned this the hard way with DEKA silk paints).
Here's a link to my page on
Dyeing Polyester with Disperse Dyes. Except in the form of fabric crayons, these dyes are not available in your local crafts stores, only from a few dye suppliers such as PRO Chemical & Dye.
(I like 100% cotton for hot weather, too. Cotton has the amazing property of insulating only when dry. When wet, it almost completely loses its ability to stop heat transfer between you and the air. Damp cotton can really cool you off, by evaporation! This means that wearing cotton on a hike can be life-threatening if the weather unexpectedly turns cold and wet, but I love it for exercising near civilization. Polyester is now made with all sorts of high-tech finishes, for people who dislike the feeling of wet cotton, but it holds heat in very nearly as well when wet as it does when dry. I rely on polyester fleece for winter camping for the same reason that I avoid polyester in the summer.)
Paula
