If I'm using pre-cuts, I don't launder any of the fabrics for that quilt and I don't use steam in the iron during construction of the blocks or top. That way, they're all going to shrink - but not until after the quilt is finished and laundered.
I'm pretty much giving up precuts though. I've found that I prefer laundering the fabric and then starching the heck out of it - it helps me keep the blocks precise.
I also like using the shot of steam when pressing open the seams, and if you do that to fabric that hasn't been washed, your block will shrivel and shrink, usually unevenly.
It's a lot of extra work, but at least I'm not pulling my hair out because the blocks are coming out different sizes. I've been using a lot of Civil War repros and there is a HUGE amount of difference in the shrinkage from one brand to another or maybe even from one line to another. I would lose the teeny little bit that's left of my mind to go to all the trouble with these CW quilts that I do only to have them come out of the final laundering looking all wonky and wavy.
