I really like to use silk as a dry fly dubbing so a while back I snapped up a lifetime supply of raw silk. I dye alot of furs and feathes for fly tying and I have alot of success with the standard acid dyes like veniards so I didn’t see any problem. Raw silk sucks up acid dye like a sponge but the problem is that the dye molecules move out of the silk substrate as easily as they move in and no matter how long I soak in acetic acid to try and fix the dye, it will just keep leaching out as long as I continue to rinse the dyed silk. A bit of digging turns up the fact that silk is a fibroin protein which is somewhat different from the keratin proteins which make up animal furs and feathers. People have been successfully dying silk for at least 5 or 6 hundred years. It’s hard for me to believe that I would need any really complex chemistry to do it at home.
Flyfshr, I also had the same idea as you and I got mylself a large amount pure tussah silk and ended up having the exact same problem as you. No matter what I tried the dye just would not fix. I used Veniards and another similiar dye. You may want to try Rit dye as it is recomended for silk along with other fibers. I have not tried to dye silk with Rit yet but I am planning on it.
Later, Jim
I think I’ve tried RIT with about the same results. Looking around the web I found a couple of sites where people were recommending cooking the dyed silk at high temperatures (like 275 F) to set the dye. I’m going to try that. After ruining some nice materials by getting them too hot, I try to be very careful to use just enough heat to get the dye to absorb into the material. I think I could cook the heck out of silk and I am going to try that and I’ll post my results.
Flyfishr, When I tried to dye the silk, I did try it a relatively high temperature but not boiling. Silk seems to be a tough fiber and I suspect it will hold up to the boiling heat. Maybe I will have to give it another try as well. Do you know what type of silk you have ?
Later, Jim
I think I have some tussah silk. If it is, it has been bleached because it is white. Last night, I dyed some with Veniards yellow dye, then I just pulled it out of the dye bath, dropped it in a can with a bit of vinager, sealed the top with foil and baked it at 275 for about an hour. It didn’t get to 275 because the vinager hadn’t evaporated when I took it out but after rinsing it thoroughly hardly any dye at all leaches out at all. The material I dyed last night would be just fine for dry fly dubbing and I think if I cooked it a bit longer and/or a bit hotter it would set completely. It looks like alot of heat is the secret to dying silk. All the dying sites I could find on the web recommend acid dyes for silk but nothing special was mentioned about setting the dye.