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YOU ASKED: I have some lovely 100% cashmere yarn I’d like to dye before knitting and am scared of ruining it. Should I use the scouring instructions for wool? I’d like to use aluminum acetate as I’m dyeing with cutch and like the pinks this mordant pulls out of this dye. Is this mordant safe for cashmere? If not does aluminum triformate also bring out pinks in cutch? Any cashmere dyeing tips are most appreciated. Thank you!
KATHY ANSWERED: If this is commercially purchased cashmere yarn, then a gentle wash/soak in warm water should be fine. You do not need to bring it to boiling with soda ash or anything as harsh as that.
I would definitely test the cashmere with aluminum acetate before you plunge in. Aluminum acetate sometimes changes the hand of protein fibers and could impart a sticky feeling. I haven’t had much of an issue with silk and aluminum acetate but I don’t know about wool or cashmere. If you do decide to use it, please also use wheat bran as your post-bath rather than calcium carbonate to avoid leaving a calcium powder deposit on the very fuzzy cashmere. Speaking from experience here.
I don’t have experience using aluminum triformate with cutch so I don’t know about using it other than it would probably preserve the soft hand of the cashmere. The color yield could be different as it’s quite acidic. Again, an experiment would provide you with important information.
YOU ASKED: Should I use tannin with my mordant when mordanting cashmere?
KATHY ANSWERED: You don’t really need tannin for cashmere because it’s a protein fiber and tannin is almost never used as a pre-treatment for protein fibers, only for plant fibers.
We have a table online that shows what we recommend for mordanting. You can lower the temperatures for mordanting or use a room temperature method, which will take longer but could help preserve the quality of the cashmere.
Here’s what I recommend for a general dye process for a very soft, delicate protein fiber where you want to preserve the hand feel of the yarn.
- Mordant with aluminum potassium sulfate at 12-15% wof. You can actually use it as a cold mordant if you leave the cashmere in the mordant bath for 2-3 days. Otherwise, bring to 130-140F for 60 minutes and let it cool in the mordant bath – overnight is ideal.
- If you are using a dye, keep the temperature low – between 130-140F. Again, because it’s a protein fiber and it already has a strong affinity to natural dyes and you are mordanting it, you can keep it at a lower temperature to avoid harshening the fiber. You may need to extend the dye time or allow the fiber to cool in the dye bath overnight.
- If you want to use 1-2-3 fructose indigo, it can be a mixed bag with cashmere as the calcium hydroxide in the bath causes both texture and washing issues because the fibers get a lot of calcium powder on them that is difficult to remove. You can try a very long vinegar soak afterwards to try to get rid of the calcium hydroxide deposit and see if that is satisfactory.
I hope this helps clarify for you. You are essentially using the standard protein fiber procedures but keeping the temperatures lower and slower.
You might also want to read:
MORDANT MONDAY: Silk, Cashmere + Heat
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FEEDBACK FRIDAY: This Week in Natural Dye Questions (iron on cashmere?)
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