How do you block acrylic yarn?

I just finished a beautiful Celtic Cable neck warmer with Lion Brand Heartland Tweed yarn, which is acrylic, and I want to make some for my friends for the holidays, but the only yarn I have is acrylic.

I’ve tried looking at various sources at how to do it, and they’re all telling me different things. Some sources tell me to steam block it, because that’s the only permanent way, while others say steam blocking is dangerous due to “killing” the yarn, and that wet or spray blocking is permanent for acrylic as well. Still other sources are telling me to blow dry it with a hair dryer or that you don’t need to block scarves.

What is the truth? How do you block acrylic yarn?

  • I don't block acrylic. I just measure as I go and make sure I'm keeping to the planned measurements. Note, putting a damp garment in the dryer is a nice refresher -- similar to the boost you get from washing and drying jeans that are feeling a bit baggy and shapeless after several days. May 31, 2022 at 9:05

2 Answers 2


Unlike natural fibers which can be blocked by simply shaping the item while wet, blocking acrylic requires heat. Many people try to wet-block acrylic the same way they would do wool, and they aren't happy with the results so they conclude (incorrectly) that there's no point in blocking acrylic. That's not true. There's simply very little point in wet blocking acrylic. The simplest heat-blocking method is to run the item through a washer and dryer. That's the easiest way, so I recommend trying that first. It should even out any slightly wonky stitches. If you're happy with the appearance at this stage, no further effort is required.

A more intense way is steam blocking. If done correctly, blocking improves the appearance of a knitted item. It smooths out minor irregularities in stitch size and overall makes the item look more polished and professionally produced. It can also prevent edges from curling. Here's how:

  1. Lay the knitted item out flat. Stretch, smooth and smoosh it until it's the shape you want and the stitches are nice and even. If it won't hold its shape on its own, use pins and/or blocking wires to hold it in place.

  2. Use a steam iron to steam it. Hover over the fabric with the iron, not touching it. As you go, pat the fabric gently to smooth it out (in areas where it wasn't already sitting smoothly).

  3. Once you're done, the blocking is permanent. Don't be scared off by the word "permanent;" it's actually a good thing because it means the gift is low-maintenance. Your gift recipients can toss it in the washer and dryer without needing to block it again.


  • Wash your item before steam-blocking it. A knitted item usually needs to be washed after knitting, because your hands aren't always completely clean when you knit (and even when they are they still have natural oils on them). If you steam block a dirty item, you can end up setting oils and stains into the fabric.

  • Knit a swatch from the same yarn (if you made a gauge swatch, just use that). Practice steam blocking the swatch until you get the hang of what distance to hold the iron from the swatch, and for how long to steam it. Actually try to over-block part of your swatch to the point of "killing" it - that way you know what it actually takes to kill acrylic, and you can avoid doing that. You'll find that it takes a lot more heat than you would expect to kill acrylic.

  • Irons often have some build-up of calcium salts in their steam holes, especially if you left water in it the last time you used it. The build-up will leave annoying little white crumbly bits on your beautiful knitted item. Run the hot iron over a towel to remove some of the crumbly bits before using the iron for blocking.

  • "Killing" acrylic is actually an intentional technique that is done on purpose sometimes. Usually for lace. It apparently gives the fabric a lovely drape, but removes all the elasticity. It's probably not appropriate for your cabled scarf, but keep it in mind if you decide to make lace someday.

  • Ravelry has some very helpful discussion groups about working with acrylic yarns, eg I don't care who knows...I love acrylic!.

  • If you love working with acrylic, consider investing in a steamer. They work better than a steam iron.


I haven't done a ton of blocking, but since I can't wear wool I've done mostly acrylic when I do have something to block. It's true that you may not need to block it, but that's not a general rule for all scarves. If the corners are curling or there are slight width changes along the length, I would try to block that smooth. The pattern may also say something specific about what you should be doing to it when you block it (say, in terms of dimensions).

I don't think any blocking is truly permanent, especially with acrylic. But you can get it to look a lot nicer with water and warmth. I've done it in two ways: steam from a hovering iron, and sprayed water warmed with a hair dryer and left to air dry. Both have worked pretty well and not injured the yarn.

For both methods, start by pinning your piece to something flat. I generally use my ironing board; I think larger pieces can be done on a bed if you don't have a blocking-specific surface.

For the first method, use your iron's steam-burst button with the plate of the iron about an inch away from the piece. You can get closer, but don't touch the yarn with the iron. I use the cotton setting because that's what my iron is always set to anyway.

For the second method, spray the piece with water. You want it wet through but not soggy. Use a hairdryer to warm it all up (and slightly dry it), and then let it air dry. You could also use the hairdryer to completely dry it.

In either case, wait until the piece is both cool and dry before removing it from the board.

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