Dying Synthetics?

I can tell you that black tea and black walnuts don't do a great job on nylon and don't seem to faze polyester thread. Good luck with Rit dye.

Others on the forums have had success in dying nylon pack cloth.

I dyed a dyneema pack black. It worked great.

I too have dyed a pack. The nylon fabric took the dye, the polyester thread for the embroiderd logo did not. It most likely will take some dye. Probably will be splotchy. Could dye the fabric but wind up with contrasting thread too. Risky proposition.

I looked up how to dye polyester a couple weeks ago. You can dye it, but it takes a different type of dye though. The process is similar to using standard RIT dye(hot water, etc). Word of caution, everything I read said that polyester will not take the aftermarket dyes as well as nylon.

Ryan

I'll second what others have said. Nylon can be dyed pretty easily and the result can be nice. Polyester is very difficult to dye, and the result is often unsatisfactory. Dyeing polyester requires a solvent "swelling agent" that softens the fibers. The swelling agent smells awful, the odor is very difficult to remove (the fabric will smell like chemicals for a long time), and it permanently and significantly reduces the strength of the fabric.

I have tried idye poly forund at Jo Ann's. It worked out beter than rit dyes. I would consider using a black dye comboed with the color you want or maybe even doubling the color.