We get mordant questions all the time at Botanical Colors so why not create Mordant Monday??? Got mordanting questions? Email [email protected]
YOU ASKED: I have several cashmere sweaters that are the most boring colors ever and I’d love to try over-dyeing. I have Orvis paste to scour with but wanted to check that the 180 degree hold for 30 minutes would also work for cashmere – I see sheep and goats on the website answer about scouring so I am assuming yes, but there is this little question in the back of my head – email to the experts it is!
KATHY ANSWERED: I think you can try a much gentler scour process. Cashmere doesn’t normally felt or shrink as it doesn’t have the same scale structure as wool, but there’s no reason to get it so hot as it’s a pretty clean fiber. That being said, I definitely felted and ruined about 50 cashmere sweaters for a customer, and our downfall was we did shibori (a lot of scrunching, pulling and stretching the fabric) and then heated up the dye bath and then agitated the goods. It was too much for these pieces.
I would do a soak in warm water using a bit of Orvus (not really sudsing at all). Maybe a teaspoon or two dissolved in hot water and then added to a tub or bucket of warm water, then add the sweaters. Then a rinse in the same temperature water and you can spin these in the spin cycle of your washer or let them drip laid out flat.
I would also mordant with the lesser amount of alum as it sometimes can cause stickiness. Anything between 8 and 10% is good. You can let it cure for several days or dye right away.
For dyeing, definitely start at room temperature and let the sweaters soak up the dye liquid, rotating it off heat for about 20 minutes. Try not to agitate in case the cashmere is sensitive to agitation. Then slowly bring up the temperature while rotating the goods. Keeping the sweater off the bottom of the dye pot where the heat congregates is important to avoid hot spots.
Have a great time and I’m very glad you are refreshing the cashmere in your closet!
YOU ASKED: I am wondering if you have a mordant method for silk fabric that does not require a heat source? (hot tap water is okay, I just don’t have access to a heat source at the moment )
KATHY ANSWERED: You can use aluminum sulfate or aluminum triformate as cold water mordants. The trick is to leave them in the mordant overnight or even for several days. A non-reactive bucket or storage tub works well and keep the tub covered so you don’t get dust or debris on the fabric. The mordant bath may be reused several times to save water and mordant.
Mix the mordant normally and then add to the container with enough water so the fabric moves freely. Then put the fabric in, press out any air bubbles and leave it, rotating it occasionally. Remove, gently wring out the excess mordant, do a quick rinse and then proceed to dyeing.