Roc-lon perma press muslin - seeking advice
 

I will be using Roc-lon unbleached perma press muslin (403) for backing several quilts and possibly for piecing, and am wondering about shrinkage and if I should prewash it. Would love to hear from others who have used this muslin.

(Also, per the Roc-lon website, there should be "2-3% Residual Shrinkage" which doesn't sound like much to me, but I dunno. Is that a lot?)

FYI, I'm using mostly precuts so not pre-washing my other fabrics. Also will not be prewashing my cotton batting. I'd like to not have to prewash the muslin, but keep hearing/reading that muslin shrinks more than quilting cottons. I want to end up with soft and crinkly, not distorted, quilts!

I'd probably wash if it's not a tight weave. Some Roc-Lon is tighter though. Keep in mind that on a 90" sq. quilt, 2% is almost 2" shrinkage.

My experience- washed some roc- lon "preshrunk" muslin in hot water- it shrank a lot. Mostly in one direction, but i do not remember which direction.

I would wash it - but I was everything washable before I cut it now.

Good points. It's a tight weave, but ... I think where I'm a bit at a loss is that I don't know how much most quilting cottons shrink vs muslin shrinkage. If there's a big difference between the two, I can see it being a lot more problematic.

I *think* that the perma press is preshrunk (the bolt label is not entirely legible), but I noticed that their website says the perma press should be a cold wash on delicate cycle and low heat to dry. Not what most of us put our day-to-day quilts thru, lol. Since I do have scads of the muslin, I think I may do a few test washes/dries at different temps and see what happens.

Unbleached muslin is one of the few things I prewash. I use of great deal of both bleached and unbleached muslin for blocks as well as backing and do not take a risk at unbleached muslin since it is not washed or treated the same way as bleached muslin.

That's interesting! I hadn't considered potential differences between bleached and unbleached muslin. Will be keeping this in mind, thanks.

I found out this the hard way, though shrinkage was not the issue. I wanted to use muslin for a quilt back. I normally don't prewash. I do spray baste. Whatever the muslin was treated with it cancelled out the sticking property of the spray baste. I started quilting and the whole back just wasn't stuck on. I thought maybe I didn't spray well so I "unquilted" and sprayed a second time. The same thing happened!! Ended up scrapping that back and using something else. Now, if the fabric I have chosen for the back seems treated or "sized" I wash it first.