I had a query this week regarding fulling yarn, and more specifically, whether Navajo-plied yarn could be fulled. I thought I’d go into the topic in some more detail here.
As you probably know, fulling (or felting if your fibre is just fibre) happens under a number of different conditions in greater or lesser degree. Temperature stress (e.g. rapidly altered hot/cold conditions), friction, agititaion and moisture all contribute to the permanent tangling of fibres which we call felting. You don’t need all of these conditions to create felt or full yarn, but two or more makes the act go faster.
So how does this apply to our yarn? Imagine you’re spinning for a project you intend to full, or alternatively, something you hope will wear really well and hold up under such conditions of stress outlined above.
Fibre content is naturally important. Two things which contribute largely to feltability are fineness and scale structure. Therefore, a fine wool, which has overlapping scales which will open and close with temperature changes and lock together under friction, will felt very easily. A coarse wool will still felt, but will take more effort. Fibres with very smooth scale structure, like mohair, or no scales to speak of like silk or superwash fibre, will be much harder to felt (although not impossible, especially fine fibres, so be wary in washing!).
Let’s say you’ve chosen your fibre. Knitter A, making the felted bag, has chosen merino, Knitter B, who wants her cardigan to stand up well to wear, has chosen a Blue Faced Leicester/Mohair blend. Think about the conditions required for felting - what techniques of spinning and plying are going to affect the success of these yarns?
Knitter A needs maximum tangleability. She doesn’t want to have to put the bag through endless cycles in the washing machine to finally achieve a result, one cycle would be great since she’s in a hurry and needs to get this bag done and dry for the birthday party she’s going to tomorrow (she’s deluded - felt dries slowly and it’s raining, but she has a hair-dryer).
For maximum tangle the fibres in Knitter A’s yarn need room to move. Therefore spinning a lofty, woollen, low-twist yarn is the key here. With plenty of air in the yarn, the fibres have space. They can move across each other and the scales can open and close, locking together. Low-twist plying and finally a large needle size - leaving more air and room between the stitches - will finish the job.
Knitter B used a soft airy yarn for her last sweater and it felted under the arms the first time she wore it. She’s a bit more cluey now and this time she’s going to use a firm, worsted-style drafting technique and create a smooth 3-ply yarn. She’s also going to add a bit of extra twist when she plies and then treat the yarn rather roughly in the finishing process. This will do two things - it will take that extra plying twist and turn it into bounce, and it will encourage a little bit of shrinkage, making it less likely for the yarn to shrink later after it’s knitted. Knitter B also chooses a needle size which will give her a nice firm, but not stiff, gauge.
So what’s the answer to our original question? Can Navajo-plied yarn be fulled? The answer of course is, it depends. Is the single spun worsted or woollen? Is it lofty and undertwisted, or a tight firm twist? Have you knitted it at a big loose gauge or a firm gauge? As you can see, Navajo-plying by itself really doesn’t have much impact on feltability.
Practical exercise: (You can tell me later whether you want me to include these!)
Choose a fibre that will felt, e.g. merino, and spin a bunch of little samples. Try a singles yarn, a woollen 2-ply, a worsted tight-spun 3-ply, a soft 3-ply… whatever takes your fancy. Knit swatches at different needle sizes and label them with loops of coloured yarn, throw them all in the washer for one cycle. What do you observe? Shrinkage should vary a lot, even though the same fibre was used for each sample.
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