Mark, your last sentance has flumoxed all those guys who want to tell you of their experiences using a different dye :D
I used Dharma Jacquard acid dyes for one batch of feathers. I have more colors and intend to use it again, just haven't had the chance yet.
Here are the directions I used from the Dharma website:
1.Fill a stainless steel or enamel pot with just enough hot or warm water for the fabric to swim freely, turn on the heat.
2.Add the dye powder to the pot and stir. Normally, in this procedure you would add 2 to 4% of the dry weight of the fabric in dye powder. For example, if you are dyeing 1 pound of fabric, use 1/3 to 2/3 of an ounce of dye.
3.Add the fabric that has been thoroughly wetted to the dyepot.
4.Raise the temperature to 185 to 200 degrees, just below boiling. Stir frequently.
5.Add ¼ cup of vinegar per pound of fabric. Try not to pour directly onto the fabric. Or add 1 Tbs. of Citric Acid per lb of dry fabric if you don't like the smell of vinegar.
6.Maintain temperature and stir frequently for ½ hour. Wash in Synthrapol or Professional Textile Detergent and warm water.
The vinegar went into the pot when it reached the right temperature and after the feathers were put into the dye mixture. After stirring and simmering for 1/2 hour I rinsed in plain water.
The only issue I had was the feather vanes seperating in the process. A friend advised me to get a zippered pillow case, put the wet feathers in that, and use the clothes dryer to dry the feathers. He said that will keep the vanes in good shape. I haven't tried it yet but I've got the zippered pillow case and will use it on the next batch.
Overall I was really happy with the results. I got a color that is not available from any feather manufacturer and it matched perfectly with the arrows I fletched.
I'm sure dyes like Koolaid work great but the range of colors in Dharma's acid dyes and the professional results can't be beat. They were also pretty helpful when I emailed with a question.
Guy