Crochet, Knitting, Tutorial

How To Block Acrylic Yarn

Taking Your Acrylic Projects To The Next Level

I love to work with acrylic yarns for many reasons but the top two are because projects made with them tend to hold their shape well when finished and the yarn is generally inexpensive. However, it is difficult to get acrylic projects looking professional because you cannot block them in the usual way.

After many of my failed attempts I came across another method which has saved many a project and made them into a high quality finished piece which my customers have loved.

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Wash And Pin: Not Worth The Time For Acrylic Yarns

The usual blocking method I use is to wash most of my projects in warm water with a dash of Wool Wash (or other gentle detergent), towel dry to get a decent amount of water out (NEVER wring your project), pin it on a board and then leave to dry for 24 – 48 hours. This process usually allows the yarn fibers to relax and take the final desired shape of your project and takes it from home-made to hand-made in a professional dash of magic.

Unfortunately acrylic is the bane of this method and I have wasted a lot of time in trying to block out my work with my usual method: I should have learned from the first time that it wasn’t going to work. The reason it doesn’t work is because the warm water is not hot enough to get to the synthetic fibers to relax but if you put it on a hot wash you risk melting your project and having to throw it out.

“Blocked” Acrylic: Usual Method

Blocking Acyrlic
Usual blocking methods do not apply to acrylic yarns.

This shawl I made for my Mother from the “Dane Shawl Pattern” by Knit Jane Knit, available on Ravelry. I was having trouble getting the shawl to sit right on the shoulders and also when wrapped up as a scarf so I thought I would block it and see if that helps.

As you can see it doesn’t even look like I have done a thing on the shawl!  The yarn has not relaxed and so the gaps created by the lace pattern are still small and difficult to see. The edging around the shawl is not even and it looks bumpy rather than having a clear and defined pattern edge. Near the top of the shawl there are still bumps in the knitting where it has clumped together and it gives the shawl a denser look which I do not want.

Overall this was a waste of time.

How To Block Acrylic Yarns The Right Way

Bring out the iron and ironing board! You heard right,  we shall need the iron that is stashed away in the laundry room somewhere, BUT we are not going to actually iron our knitting. “Huzzah” I hear you shout!

The easiest way I have found to relax my yarn fibers is to put your iron on the highest steam setting on a medium heat (if possible) and hover about 1 – 2 inches away from your work; if you have to have your iron on the highest heat setting then increase the distance to about 3 inches so as not to burn yourself. The steady stream of steam (trying saying that fast!) heats up the little synthetic fibers enough to allow them to relax and get manipulated into the shape you want.

When I’m working a project in this way I make sure that I am stretching out the fabric with one hand just after I have steamed it. For smaller projects this works great and if you are quick enough you can do it with the larger projects but it does take a little practice.

If you have got a large blanket or even something with an intricate design then I would recommend pinning out your work in advance and then going over it with the iron and readjusting the pins to compensate for the fibers relaxing and giving you more ease to play with.

When you are going over your knitting you rarely need to stay in one place for more that a few seconds, otherwise you may burn yourself on the steam and also risk your knitting. However, if you are up against a detailed pattern or just have an area that is being difficult then I’ve found that coming back to an area after a couple of minutes and re-steaming and stretching it usually sorts out the issue.

Why You Should NEVER Press An Iron To Synthetic Yarns

Acrylic is not the only yarn you’ll come across that works well to steaming when blocking, generally most synthetic yarns work well. However, as I mentioned above if you are having difficulty with an area you should just go back over it again and NOT be tempted to press the iron to your work.

This will be one of the worst mistakes you will ever make with your fabric! Directly pressing the iron to your work will result in tears and frustration as the synthetic fibers begin to melt, get stuck to your iron’s plating and warp your stitches into something unrecognizable. At this stage there is little you can do unless you’ll be in a position to frog your work and re-knit the area that has been destroyed. I have only ever done this once and I ended up throwing out my project and starting from scratch.

If you are concerned about accidentally touching the iron to your work (I know kids and pets will often bump into you) then I can highly recommend a protective mesh cloth. I will often use one myself, especially if the yarn is under DK weight or if there is a lace pattern.

Steam Blocked Results

Relaxed synthetic fibers after steaming

A close up after the steam blocking process has happened shows that the gaps made in by the lace pattern are much further apart and much more relaxed. The fibers in the acrylic yarn have relaxed and set in their final place (before the next wash) allowing the pattern to be shown clearly with all of the detail showing through.

Steam blocked shawl

The shawl has now been blocked and as you see the pattern and lace gaps are a lot more noticeable. It’s difficult to see in the two photos but by blocking it out this shawl has gained an additional 25% in size. I’m really please with how the clumping at the top of the shawl has now dispersed and you can see the pattern really well at the top even from a distance.


Just a quick round up to recap on what we have discussed:

  • Traditional wet blocking does not work
  • Steam blocking with the applied heat relaxes the synthetic yarns
  • Direct heat from the iron will ruin your work

I hope you have now learned a valuable skill in taking your projects from home-made to professional finished pieces. If you have any questions or would like to share your experiences with steam blocking then please leave a comment and let me know.