Monday, August 08, 2005

To Block Acrylic or not to Block Acrylic, That is the Question

red heart acrylic swatch blocked with a steam ironI keep reading that it's impossible to block acrylic knits - that it will eventually spring back into its original knitted shape. Then other resources say you can block it by steaming, or "kill" acrylic yarn by ironing it.

I made a swatch of 100% acrylic Red Heart, in preparation for the Stitch-n-Bitch Big Bad Baby Blankent, modified to fit my DD's twin bed. I should've taken a before photo, but trust me, it was less than a perfect square. The seed stitch border warped at a looser gauge than the stockingnette squares that puckered like ribbing at the edges. I thought this to be the perfect time to test the acrylic theory.

The answer is YES, you CAN block acrylic knits. Though it flattens the knitting slightly, the result is a much smoother and softer fabric that now drapes quite nicely.

I used a standard Black and Decker home iron with 3 steam settings and a Teflon surface. The acrylic setting is the lowest temperature, but there's no steam available at that level, so I turned up the iron to the minimum temp setting for steam, in between polyester and cotton blends.

With the steam level set to medium, the swatch directly on the cloth covered ironing board, I took a deep breath, and VERY lightly touched the swatch with the iron, moving it circles, without letting its full weight rest upon the swatch, while slowly pulling the knitting into shape with my other hand. Then when the swatch felt slightly damp, I turned off the steam, and pressed the swatch a little bit more to dry it into shape, while still not letting the full weight of the iron press on it.

Whoever says that you can't block acrylic yarn, apparently never tried this method. This swatch now has perfectly square corners, and after 6 hours, has not crept at all back into its original knitted shape. I've never been a fan of Red Heart acrylic against my skin, but now it's smooth enough to be worthy. The key is not to press too hard, don't let it get too hot, work quickly, pull it into shape a little at a time, and iron it until fully dry. Above all, test your method on a swatch before trying this on a fully knitted project. My next test will be to throw it in the laundry, so I'll let you know tomorrow....


  1. I used this very yarn to make my daughter a poncho. I just can't see making a garmet for an 8 year old that has to be hand washed. I steam blocked it and it worked like a charm!! It was so soft when I was done and my curling edges were perfectly flat. Good luck on the blanket.

  2. Would you recommend trying this with a very old iron? I was just about to try this with a piece of knitting made from Super Saver, but I'm afraid of what will happen. Do you have any other recommendations for how to get the lumpiness/curling out of the piece? It's about 15" x 25" stockinette.

  3. Thank you so so so! much for this post. I found it trying to find out if its possibe. I'm so glad to hear to help it makes the final knitted product, drapy and smoother(as I'm currently knitting with acrylic yarn). I'm bookmarking this =D

  4. Thanks so much for posting this! I'm working out a star garland pattern in crochet and the edges were curling pretty badly. I was hoping I could block them as I'm working with an acrylic yarn.

    I put a dishtowel over each star and then gave it a good steaming. Now I'm letting them dry flat. We'll see how it goes...


  5. Thanks for this post. I'm now encouraged enough to try it out. I did a scarf with a nice pattern, so I hope it doesn't flatten too much. Of course, that'll still be better than its curling edges...grrrr...

    Thanks again. Merry Christmas!

  6. If you don't want to flatten your stitches, just steam them without touching the fabric with the iron.

  7. So, what happened after throwing it in the laundry?

  8. It stays blocked permanently.

  9. If you don't mind me asking you did it before you washed it for the first time and no pins or blocking wires are needed nor wetting the fabric prior to the blocking is needed either right?

    Maria B.

  10. That is correct. I just simply used a steam iron, with no blocking pins. I've only done this one other time with acrylic on a crochet scarf, and it turned out beautifully.

  11. I have never blocked anything but this time in making an afghan the pattern is a wave and all the waves parts are puffing outwards. It looks like it could be its final results but wondering since the right side waves puff out what side of it would I steam?

  12. Thank you so much. I just tried it on a scarf and it worked great!

  13. Going to try this as soon as I get a decent-sized swatch worked up. I can't crochet with wool - ITCHY! - and cotton yarn is just so blah looking. Acrylic is so versatile, too! After that, things get too pricey for me. Have you ever tried iron-blocking metallic yarn?

  14. I'm a very beginning knitter making my first piece. I've been using Red Heart Super Saver yarn to knit an afghan using a Knifty Knitter loom. I'm using two strands at a time for a nice full look. The larger pieces are ribbed, the smaller pieces (which will go in between the big ones, like stripes) are a stitch they call "fashion stitch", but which I've also seen called reverse stockinette. It's essentially ribbed, too.

    I just want to confirm that I am NOT supposed to block this with steam, because it's ribbed. I'm thinking of assembling the whole thing (sans fringe) and then simply washing on gentle in cold water (per directions) and laying out all the pieces on my bed to dry in the nice square shape I want.

    I really *do* want it to look as "finished" as possible, though. Is this as far as I can reasonably go?

    Thank you for any response you can give, and sorry if these are dumb questions. I really am a rank beginner.

  15. Marcia, I have not tried to block metallic acrylic yarns.

    Marcy, I do not have any advice to offer, other than try it and see what you like best.


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