this is the "recipe" that i found on the leatherwall. probably something similar here too, or maybe the same fella.
works great tho kool-aid offers limited colors compared to rit or others. someone mentioned this recipe was originally offered on a fly tying forum...so they outta last and deal with water well.
For those of you who process your own feathers for fletching, here is an easy method for adding color to them. I found a How-To on the net about dying feathers with Kool-Aid and decided to try it. So far I have made green and orange and the color transfer is very good. I have soaked them with water to see if the colors would run, and they are colorfast. Here is the link: Dying Feathers 101 from
www.ronnlucassr.com, a site for flyfishermen. You will need several packets of Kool-Aid in the color you like, and three bowls. Prepare one bowl for washing/degreasing. In this bowl put water and Joy liquid soap. Agitate the feathers in this and let them set while you prepare the other two bowls. The next bowl contains water and a dash of white vinegar with a couple of drops of Joy soap. The last bowl is a microwave safe, 8" x 8" dish 1/3 full of water with a splash of vinegar and a few drops of Joy soap. Into this bowl dissolve two packets of KoolAid. Transfer the feathers out of the degreasing bowl and into the water/vinegar bowl and let stand for 5 minutes. Transfer the feathers to the Kool-Aid dye in the microwave safe dish. Put the dish in the microwave and nuke it for 2 minutes, let it stand for two minutes, then nuke it again for two minutes. Remove it from the microwave and set it on a pot holder. Examine the feather. If it is too light, let it stand longer. The Kool-Aid acts as an acid dye, and it does not matter how much water you use. The dye in the Kool-Aid will transfer from the water into the feather. The water will actually get clearer as the feather absorbs it. If you cannot get a dark enough shade, remove the feathers, add another packet of Kool-Aid, and repeat the microwaving process. Once the desired shade is acquired, rinse well and dry the feathers.