Message: Hello. I hope you can help me with my problem. I've never used a dye for anything except for tye-dying t-shirts in high school years ago. This time, it's not for fun. I bought a very expensive swimsuit last year, only to wear it twice. I hand washed it and layed it on a wooden drying rack(eeek!). I tryed using stain remover and pretreated it with Tide numerous times. I found that it only made it worse. I would love to be able to wear it again, if possible. It's 80% nylon and 20% cotton. I read that the blend is commonly dyed. The stains are still there, with lots of fading around it. Could you PLEASE help me. I need to know basically what brand, colors, and process to use. I'm thinking it would be a miracle, but I know it's got to be easier than I think.

It's not nearly as difficult as dyeing polyester, at least.

Nylon can be dyed with acid dyes, which are common and easy to use. You can actually dye nylon with all-purpose dye, such as Rit brand dye, because one of the ingredients is acid dye, although I would strongly recommend you avoid all-purpose dye for cottons. You can ignore the 20% cotton in your swimsuit. Rit works with nylon, if you add vinegar and use water as hot as the swimsuit can tolerate, preferably for an hour or more.

It's best not to try to produce a single color, because the stain will probably still show. Try to do a combination of a couple of colors. It'll be more interesting that way, anyway.

Acid dye requires the use of a mild acid, such as vinegar, plus heat. See the following for instructions, buying the dyes and auxiliary chemicals from the same site:
http://www.prochemical.com/directions/WF_ImmersionNylon.htm
http://www.prochemical.com/directions/WF_DirectApplicationNylon.htm (Hand apply a mixture of two or more colors)
http://www.prochemical.com/directions/OneShot.htm

Or, if you choose to use all purpose dye, see this page:
http://www.pburch.net/dyeing/FAQ/rit-tie-dye.shtml

If you use water that is not hot enough for optimal results, the dye will gradually wear off, but you can always repeat the process, if necessary.