Can you dye 100% polyester fire retardant fabric

poly is not known to take a dye real well..cottens work better. i have heard of a cold water dye and dying curtains in a bath tub.

Dying polyester is almost impossible. I have tried, even the Rit dye for synthetics didn't work. What about paint. Either fabric paint or mix regular paint with a fabric medium. It's something you add to paint when you want to paint fabric and keep the paint soft. You will find it in the paint section at the craft store. Look for Plaid brand or Decoart. Those are the only two brands that come to mind.

Polyester is colored In the Fabrication process... it is a NON-porous plastic, and will not absorb dyes. You MAY have some success with paint, but since it is in a family of plastics that behave like paraffin, it is more likely to shed any external colorant.

Hi Amy, Here's a link that should help: https://www.ritdye.com/2016/05/06/how-to-dye-polyester-synthetics-and-plastics-with-rit-dyemore/

Good luck!

Many, many years ago I wanted a Kelly green lace shower curtain, but there was no such thing to be found. So I bought an expensive white one and figured I would dye it. I read the instructions and it explicitly said it would not dye 100% polyester, but I figured they didn't mean me. So I dyed it Kelly Green, twice - only it turned out to be a spotty Dirty Grey, twice. In the end I painted it Kelly Green and I was happy. In the case of your curtain it doesn't seem likely that you are ever going to get Navy Blue dye to stick to 100% poly. Paint works but you have to do both sides and you would have a gianormous task ahead of you. Maybe you could mask it off in stripes and spray paint Navy Blue.