My understanding is that one should block 100% wool by soaking in hot water and reshaping to dry, which will felt the fibers enough to keep its shape. Acrylic, on the other hand, does not felt, so instead you steam-block it and/or "kill" the fibers (ever-so-slightly melt them together) by holding an iron at a distance, so that it does not completely melt the yarn.

What if I am knitting with a blend of wool and acrylic? Assume this is a wearable article that I would like to remain soft.

(Steam blocking for wool is another method I've seen, but since this is done by placing the iron directly on a sheet/towel on the yarn, rather than holding it at a distance as for acrylic, I'm assuming that would not be a good idea for a blend.)

Some sub-questions I have about this:

  • How does the fiber content (say, 25% wool vs. 50/50 vs. 75% wool) affect what method(s) to use, and the result?
  • Is the acrylic method of steam blocking (from a distance) effective on wool?
  • Are there other blocking techniques that would work on both types?

1 Answer 1


Data point: I successfully blocked a mixed-fiber scarf by soaking in warm water! It was made of fingering weight yarn, content: 75% superwash merino / 25% nylon.

For an arbitrary mixture, the safest method would definitely be to make a test swatch and see how it responds... but since I don't always swatch, the next best thing is to try blocking in order of least to most potential for damage.

  1. Block by soaking and letting dry
    This will only be effective on the natural fibers in the yarn. This will not have any effect on the plastic fibers, but will not damage them either. In my case - 75% natural fiber - this was sufficient to retain the shape.

  2. Steam block
    This will affect both types of fibers, so it should be effective. The danger here is that you over-heat and melt the plastic fibers. This is permanent! So I would only use this if the previous step did not work, and on low heat. Wool and other natural fibers won't be damaged by that either.

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