Thursday, March 1, 2018

Guest Post - Barbara S

In my weaving life, I learn something from every warp.  Sometimes the lessons are based in exploring different structures, techniques or yarns; other times they come from air-brained moments of inattention.  My latest adventure was a puzzle that required thought and analysis.
As a student in the Olds Master Weaver program, Level 1, one of my assignments was weaving a value gamp composed of six colours of woollen-spun wool. The goal was to complete a twelve-inch grid with each cell measuring two inches after finishing.

Using information from previous work with my chosen yarn, I forged ahead and produced a sample with five colours behaving predictably and one very long stripe that was not conforming in either warp or weft directions.

As my frustration grew, I recalled that, when winding the warp, the colours had not felt the same when running through my fingers. Some had felt smooth and fine while others gave the impression of being rougher and bulkier.  It was time to examine the yarns in more detail.

First, I checked the staple length of the fibres, pulling apart the strands and extracting small quantities of wool.  I found that the longest staple lengths varied between 1" and 1 3/4" depending on the colour.  These results were repeatable over three samples. Next, I looked at the fibres under a magnifying glass and noticed differences in the diameters of the fibres as well as the degrees of crimp.  The longer samples were greater in diameter with less crimp. Since we know that these differences can translate into variations in fulling properties, I hoped I was starting to decipher the puzzle.

Yarn from a cone is generally quite inelastic and needs to be wetted to awaken its resilience. In an attempt to discover any variations in how the yarns responded to wetting, I measured equal 15-inch lengths of all the colours, tied them together evenly at one end, and gently washed the bundle.  After drying, two colours were longer than the others by about half an inch. Interesting ...

As a final check, I measured each colour on a McMorran yarn balance, so that in theory I had the same weight of each yarn - 1/3,600th of a pound. My theory was that if these yarns had all been spun to the same yards per pound, the resulting strands should have been the same length - or close - given  my basic measuring technique and acceptable variation between processing batches in the factory.  The results revealed significant differences between sample lengths of different colours both before and after washing.

The measurement techniques used in these experiments are crude; nonetheless, they do provide an overview of what is happening with these yarns.  The results were enough to convince me that when the fleeces were selected and blended in the mill prior to spinning, there had been definite differences in the characteristics of the wool used.

As a final test, I purchased another cone of the problem colour from a different dye lot.  It worked!  The next sample finished with straight hemstitching and no wonky selvedge.

Lessons learned included the need to trust my own perceptions of a yarn, strategies for checking yarn collections for similar properties, and the importance of sample, sample, sample!


Peg Cherre said...

Lots of learning there, for sure. I rarely weave with wool, but bet there is lots to learn with my preferred yarns (tencel, silk, and cotton), too, but I must admit, I'm not that dedicated to do that much detective work.

Sharon Gardiner said...

Goodness Barbara, that is some good research and examination. Weaving can be unpredictable as much as we use our knowledge and experience to have the outcome expected.

Not long ago I had a similar sort of experience. 15 years ago I had made nice cuddly and soft blanket for the end of my bed. I loved the lightness and soft hand and feel for Sunday afternoon snooze.

When we were doing blanket projects at our guild studio on the 100" loom about 3 years ago I wanted to use the same yarn. I believe sett was similar and finishing was definitely the same. But the end result was not cuddly at all.

Then a friend used the same yarn for part of a blanket as I had sung its praises. Her experience was different yet again, even following the sett recommended by the yarn manufacturer.

We put all three out together for a comparison once her blanket was finished a month ago. All three were very different but same yarn manufacturer and supposedly same material and yardage. I haven't done the level of investigation as Barbara but this experience reinforces the need to sample even when using a yarn that you have used at other times.