Thursday, August 9, 2018

Dyeing Wool Interlock

As I write this post (Wednesday) it's the first day back to school for my oldest. Life should finally calm down to a routine, which includes more regular blogging! I have such a pile up of projects!

While my oldest is off to first grade, my middle will be starting her first year of preschool. She will be attending an outdoor forest school two days a week. She is extremely excited, but this mama wants to make sure she is properly clothed for the elements. My kids wear wool pants almost exclusively (yes, even in the summer, they wear wool shorts) so naturally my mind turned to wool when I was thinking about my daughter being outside. I decided to make some her some leggings from wool interlock. I knew they would be hard-wearing, and warm. She will probably still need some sort of rain/snow-proof layer on top, but I want her base to be nice and toasty.

Just before we moved, I ordered some 97/3 feltable wool interlock from Nature's Fabrics. It is 3% spandex for amazing stretch and recovery. There are instructions on the NF website for how to felt this wool (yes, on purpose!). Once felted, the wool is super dense, but still stretchy. It comes in a natural color so that it can be dyed.

This was my first time dyeing anything. I tried to read as much as I possibly could about dyeing before starting, as well as asking for help in the Nature's Fabrics Facebook group. In the end, I learned more by doing, which is not super surprising. The one piece of information that seemed the most important was that just any old dye would not be the most efficient for wool. Silk and wool are animal fibers, not plant fibers, so they require an acid dye like this one from Jacquard. I ordered mine from Amazon.

The amount of dye you need (it comes in a powder) depends on two things. First, the color you wish to achieve; and second, the weight of the fabric. For example, light colors such as yellow, grey, and pink do not require as much powder as dark colors like navy. Additionally, if the weight of your fabric is high, you need more dye. As an example, 16 oz of fabric dyed pink only requires .25 to .5 oz of dye, but 16 oz of fabric dyed navy requires up to 3 oz of dye. These ratios weren't exactly clear to me until I dug deeply into the directions from Jacquard (see page 2). Furthermore, I learned that other variables can effect the color (more on that in a bit).

In total, I have done 4 different dye sessions. Here is a brief overview of the methods I used. I purchased a stainless steel pot (cheapest I found was online through Wal-Mart) and wooden utensils that are only used for dyeing, not cooking. Rubber gloves were also useful to have, as well as tongs (I didn't have any for dyeing but I will be getting some!). I used Synthrapol, a special soap, for washing the fabric after dyeing.

Session One
Item: Already sewn wool/spandex interlock soaker 3 oz
Dye: 1/2 oz of 626 Navy Blue
Method: stovetop

If my math was correct, this amount of Navy dye with this size of item should have resulted in a true color. However, the soaker turned out to be almost black. I was dyeing it to cover up some staining and dinginess, so I'm fine with it, but I do with it were navy. I forgot to measure the cover before I dyed it but I do not think there was any shrinkage. The thread and tags, presumably being polyester, look tinted but not completely dyed. If you look closely at the inside back waistband in the photo below, that is the only portion that looks navy.

Session Two
Item: 1/2 yard of felted wool interlock (forgot to weight it!)
Dye: 1/2 oz of 608 Pink
Method: stovetop

I was absolutely thrilled with the way the color turned out with this piece. What was not thrilling was the amount of shrinkage (in length only). The piece had already shrunk significantly during the felting process (we're talking 10"+) and it felted another 3" while dyeing. After dyeing this piece I realized I did not have enough material to cut two legs for the leggings I wanted. I ended up ordering another bottle of dye in the same color to use on the other half yard.

Session Three
Item: Pair of light blue machine knit wool pants from Sloomb plus interlock scraps, roughly 16 oz total
Dye: 1/2 oz 638 Silver Grey
Method: stovetop

Due to the amount of shrinkage the previous time, I was reluctant to turn the heat up to near boiling. If I shrank the pants in length they were not going to fit my daughter. I kept the heat at medium. While it was successful in preventing shrinkage, this was the only time I had uneven dye. Either I did not mix it into the water well enough, or it was due to the lower temperature.

Session Four
Item: 1/2 yard of felted wool interlock (forgot to weight it...again)
Dye: 1/2 oz of 608 Pink
Method: stovetop

In an attempt to color match from Session Two, I did everything the same. Except that I forgot to add vinegar. Face palm. I do not think it affected the color although it will probably effect how well the dye sets. I was incredibly disappointed to see that the color was nowhere near the same as before. The shrinkage was the same, but the color was not. My only theory as to why, is the amount of water in the pot was different from one session to the next. The instructions simply say to make sure there is enough water for the fabric to move around freely. Nothing exact. I'm fairly positive I used more water during Session Four, and the color seems more diluted. I'm very frustrated that a variable like this could so dramatically affect the outcome and yet NOT be noted anywhere in the instructions.

Left, Session Two
Middle, Session Four
Right, Session Four and a Half

Session Four and a Half
Item: interlock scraps
Dye: remains of dye bath from Session Four
Method: stovetop

After removing my yardage from the dye bath, I tossed in some scraps of natural interlock (dry). I didn't heat it. I stirred it a bit. I did wash with Synthrapol after but I forgot the vinegar here too. These scraps turned out great although a lighter color entirely.

After all that dyeing, I was left with some really random pieces of fabric that I wanted to turn into pants. I attempted to copy a pair of interlock pants I already had, but I should've just used a pattern because I was constantly futzing with my version. With some fancy cutting and slightly off-grain maneuvering I got three pairs of pants from one yard+scraps. The grey pair was actually fabric that was cut for another project (a sleep sack) and I pieced it back together to make pants. They're just about the most ugly thing I've ever sewn, but since they're just going to outdoor preschool I'm not that concerned! The last pink pair, I prepared some cuffs for extra length and I'll add them when needed. Right now the hem is raw and they're plenty long enough.

Now I want to hear from experienced dyers! Does the amount of water matter as much as it seems? Any tips on even color? This was a fun experiment but I'm probably not jumping back into it anytime soon unless it's NOT with wool!


  1. Okay, so it definitely seems counterintuitive, but from everything I've read, the amount of water doesn't matter. The dye you put into the pot should theoretically end up in your fabric no matter what amount of fabric you have, which is why you're supposed to do things until the dyebath is clear.

    Sometimes blotchiness is because the fabric wasn't evenly wet to start out with--could that have been the problem?

    1. That does make sense! No matter how much vinegar I poured in, I never got a dye bath to run clear. And it’s definitely possible the batch that turned out blotchy wasn’t wet all over. Thanks for the help!


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