Thursday, July 16, 2015

Is my paper shrinking?

OK folks, I measured before and after.  Paper does indeed shrink when it is ironed.  Even the fancy “paper piecing” newsprint-style paper whose manufacturers claim it won’t shrink and curl.  But here’s the kicker: it seems to go back to its original size after cooling down.

IMG_9863This week I needed some airplane blocks, and paper piecing cropped up again.  I had to choose between fussy templates, free-form plane blocks that would each be a little different (sorry, this layout will look better with uniform blocks) or the not-so-favourite paper piecing. 

What drives me nuts about paper piecing is that sometimes things don’t line up where they should, even though precision is the whole point of paper piecing.  If I sew exactly on the lines, things should be just the right size in just the right places and should line up just so when I join up pieced sections. That word “should” definitely doesn’t mean “does”.

While I was trimming along the printed seam allowances for the pieced sections of this plane, I noticed that the lines were not where I expected them to be according to my ruler.  The section was a rectangle, and should be 6” long, or 6 1/2” unfinished.  It was 1/16 of an inch short.  That’s small, but it adds up, and because the shrinkage was greater in one direction than the other, it messed just a bit with the aspect ratio of the design.

Today I printed the paper foundation and measured.  It was exactly the size it was supposed to be. Then I ironed the paper and measured again.  Ha!  It did shrink!  Can’t blame it on stitching puckering the paper, or any such thing, because there was no stitching yet.

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You can see I lined up the 1” mark on the ruler with the same line in both pictures, but that dark line on the far right is at the 7 1/4” mark before pressing, but about 1/16th less after ironing.

And, just to mess with my mind, here is the same paper after it has cooled and relaxed for about an hour.

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Really?  It’s back to the size it should be.  I tried this with a plain 3” square too, and got the same shrink-unshrink result.  Clearly there is some physics of materials at work here. I really don’t feel liked dusting off my physics degree (I do have one) so here’s what I am going to do: I will sew one seam at a time on my paper pieced units, and wait a nice space of time for the paper to cool and relax before I go sew the next seam.  Then I’ll see if my pieced sections end up the right size and line up “just so”.

While I wait for things to cool, I’ll just stitch up these cute little framed nine-patches for my alternate blocks.  These are NOT giving me any grief!

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18 comments:

  1. I have two daughter-in-laws that are pilots. I need to learn to make some airplane blocks; but they look difficult. Yours looks wonderful.

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  2. I guess that's why when I PP my DJ blocks they are always too small, so recently I have deliberately making them extra large on the outside of the blocks. Why did it take me so long to learn this lesson? It's not fair!

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  3. Okay, the shrinking and un-shrinking paper is kinda crazy. But I have also found a similar thing with fabric. Hot blocks stretch. So it is better to let them cool before squaring them up.

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  4. Who'd-a-thunk-it? This really messes with my mind! I know what you mean about the lines that should line up, NOT lining up; I had similar issues with my cow blocks, that are pp.

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  5. That is just plain crazy, but I'm glad to know this. If I run into similar problems while paper piecing, I will already know the solution!

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  6. I've had the same issues with paper pieced blocks not always lining up exactly perfectly as I thought they would - since that's the whole benefit of paper piecing, right? I always thought it was something I was doing wrong. Glad I'm not the only one.

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  7. Very interesting. I have done a lot of paper piecing. I usually piece all the blocks at the same time if they are the same. So that could be any number of blocks. Maybe that is why I didn't notice the shrinkage, because by the time I made it back to block one it had cooled down. Thank you for the information.

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  8. Gosh - very interesting, I'd never really considered THAT aspect of foundation paper piecing before. Sometimes I press and sometimes I don't - oh dear!!

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  9. I've never heard of that shrinking issue or ever seen it mentioned so your post has been enlightening. It's a good thing you noticed it.

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  10. When I paper piece, I use a wooden wallpaper roller (recommended by RaNae Merrill, see her website) for pressing the fabrics over after I stitch each one on. No iron, no shrinking, ta da! I do use the iron once the block is completely pieced but I let them cool before trimming the edges. I didn't know I was avoiding the shrinking, just like using the roller better.

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  11. That is one of the reasons I rarely paper piece. When I do I never sew through the paper I always fold on the sewing line and then stitch as close to the fold as possible without stitching the paper. The bonus is no paper to remove at the end.I glue with a washable glue stick the first piece to the paper to hold it in place.

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  12. Wow! I never realized that. Thanks for letting us know. The plane blocks are very cute. Can't wait to see it all laid out with the alternate blocks. Love blue and white.

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  13. Another reason (and the list is long, for me) to hate paper piecing!!

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  14. That is really interesting! I'm glad you tested it and let us know. I love the fabric you are using for the airplane blocks, the blue is really pretty and I always love fabric with stars.

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  15. After my first workshop for paper piecing, the instructor asked me what I had learned; my reply was that I learned that I never wanted to paper piece again. And I didn't even imagined a problem like yours could exist. Glad I'm not into that, right now anyway. I do love your airplane block and especially the fabrics! ---"Love"

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  16. Who would have guessed that the paper would shrink and then reexpand?? Paper piecing is not something I enjoy doing and haven't done much, but I will keep this in mind. Your plane is so cute!

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  17. THanks for this now I have a great excuse when my paper piecing goes wrong. It's not my fault the paper shrinks.

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  18. I wish I would have read this prior to doing that butterfly!! The block was supposed to be 12" when I finished it. . . it was 11.5" And I had some issues with things not lining up. I see them but decided to just move on and keep going. I see the not so accurate parts. I don't think Cally will ;)

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