Saturday, July 17, 2010

Ye old Sig Vat

This winter there was a group decision amongst my weekly weaving students about the idea
of starting an authentic old-style indigo urine vat. I had first learned to dye indigo this way with
Norman Kennedy in 1975 when I was weaving traditional blue and white blankets. At that time
I was committed to using all handspun yarns and it seemed also appropriate to use the most traditional method of dyeing with indigo. Over the years I have switched to synthetic indigo, lye, and hydrosulfite but I had always hoped to one day go back to dyeing with the urine vat.
With so many willing collectors of the essential ingredient it was hard to pass!
Here is Alison adding her husband George's contribution. We decided to do a 30 gallon vat
so that we could dye substantial quantities and that is alot of urine! It took about three months
of six willing husbands peeing into plastic containers; by May we were ready for the next step.
I had saved about 4 pounds of a very fine lump indigo and for this vat we used about 12 ounces.
The indigo was put into a sock with a rock tied to the bottom so that the sock would sink to the bottom of the vat.
Here is Jackie adding the sock and indigo to the vat. At this point the smell is pretty strong (as shown by Pat holding her nose). Actually once the urine ferments the odor is basically ammonia.
The indigo then sits in the vat for a week or two. Notice the color is still very amber.
About every three days I would go and squeeze the sock to disperse the slowing dissolving indigo into the vat. The heat of late June and July here this summer was really ideal for getting the vat to work.
After another few weeks we were ready for the first dip. The amazing thing about a urine vat, as compared to a hydrosulfite vat, is that you can get a much greater range of colors...from pale blues to the darkest navy.
Here are our first skeins after only three dips. Now they just need to air out for about a month to get rid of the smell!


  1. SO smelly, but seriously, such a fantastic indigo vat, kate. i'm happy you followed through on the inspiration to do this!

  2. i have a indigo sig vat as well, and dont have any problems dyeing with it even when temps are in the 60Fs. i find that a castile soap works great for removing the scent without having to air things out. and i like that the vat doesnt have to be fed or tended much...but my family makes fun of me.

  3. @leFiligree...
    thanks for you comment and for sharing your urine vat experience with everyone. the castile soap rinse sounds like a fantastic idea! thanks so much for mentioning it.