shrinkage problem
 

I am starting to make a chevron quilt with precut layer cake fabric. The fabric was expensive and good quality so I am alarmed at what happened. i decided to lightly starch the 10" blocks with best press before I started sewing and after pressing three blocks, they looked off to me so I measured them and they were 10" x 9 1/2" I did one more very carefully, measured it before I starched and it was 10x10. pressed very gently and they still shrunk. Just glad I noticed before I did all the blocks. ANyone know why this happened.

I don't know but, I would say they are not cotton.

Fabric sometimes shrinks. That is the nature of the some material made of cotton.

Normally when fabric shrinks it shrinks all the way around, not just in one direction. What kind of fabric was this?

I believe all cotton fabric shrinks more lengthwise than it does crosswise (or is it the other way around) knowing this when you dampen the fabric and iron you will have more shrinkage one way than the other. I think it does not matter if it is "good" fabric or not it will shrink one way more than the other. Cheaper fabric may shrink more than better fabric.

Not really. I'm a pre washer and I measure before & after I wash & dry. If it shrinks, 99% of the time it's width of fabric (selvedge to selvege). If you start with a yard, you normally end up with a yard, but a bit narrower. I've been told that the fabric fibers really don't shrink, but the fabric is stretched during the printing process and when washed it returns to it's original dimensions.

It's cotton fabric and you applied the two ingredients that will make cotton shrink ... moisture and heat.

I am surprised it shrunk so much (1/2" in a 10" block is a LOT), and I'm also surprised that it shrunk only in one direction because it means that every piece in the block was set in the direction (ie all had the weft and warp oriented the same way). It wouldn't shock me if you were strip piecing as all the strips would have been cut in the same direction, but you were using pre-cut squares ... so every time you grabbed a square and cut it ... the weft/warp was oriented the same way.

If I were you I would starch and press all the blocks to get them all to shrink, then trim them down to 9.5" (or 9" if you can't trim one side without messing up the pattern).

Sorry this happened.

Thank you for explaining. I will be checking closer from now on.

I had a five inch square shrink one half inch in one direction. If that had been a 42 inch strip, it would have only been 37.8 inche after washing.

I have measured hundreds of pieces before and after washing them.

Some do not shrink at all. A very few have stretched. Most shrink some - usually more in one direction than the other.

I can not tell ahead of time what the fabrics will do.

I also had a stack of blocks that were about 10 x 10 before xoaking in hot water. Most of them shrank.

Some of the spendier lines had worse manners than some of the less costly ones.

Guess what???
............. you have just discovered one of the merits in pre-washing.
At least you know what you are working with and less likely to get surprises.