Why would a LArmer request ...
 

request that the backing be pre-washed, but not the quilt top or quilt top fabrics? Won't they then shrink at different rates? I am puzzled.</SPAN>

no idea dosent make sence to me

She probably assumes that the top is already washed.

I agree. I would assume that everything is prewashed. The original sizing is hard on needles, messing up her (or his) work.

I'm surprised. I prefer for it to be consistent. Both washed, or not washed. I use a new needle for every quilt.

What type of fabric was the backing? I know batiks from Sew Batik recommend washing with synthrapol before using. Extra dye and wax used in the process need to be removed.

Not sure, but I'm thinking her machine may have a problem with unwashed backings. The sizing and other finishes may cause her machine to skip.

With moderate quilting, shrinkage of all the fabrics in a quilt will be controlled by the batting. That is, with moderate quilting, a fabric will not be able to shrink more than the batting shrinks. The only time different shrinkage rates become a problem is when the quilting is far apart.

Fabrics when washed alone will shrink at their own rates, as there is nothing to stop them from shrinking to their max.

I would go with whatever the front is. I would also ask her/him directly why they want it pre-washed. It's better to know what their purpose is than ours.

I agree I would ask!!!

If you're wondering ... ask the LAQ'er!

Amen! That's the only person who can tell you!

Definitely ask, because both should be washed, not just one layer, otherwise shrinkage may be uneven. In fact, I was just looking at some Pellon cotton batting in JoAnn's and they suggest washing it in hot water before use due to shrinkage.

Never heard of this. Hard to understand.I will be watching this one.

That's a new one by me! I have used many Long Arm pro's over the years and none have ever asked for the backing to be prewashed.
Do let us know what your L/A has to say as to why this is required.

I would do whatever she asks. I'm just glad she's there!

I bet that is the reason. she figured you had already prewashed your top. I imagine (andI've never longarmed before) that when they stretch the backing to quilt and it hasn't been washed, then it might shrink and draw up real bad, making the quilt look puckered. A longarmer's reputation is often by word of mouth and if the work looked bad agtter washing, it might fall back on her. That is just what I think. (That and a buck will get you a cup of coffee)

I am a longarmer and the only thing that I request for the backing is..make it 6 inches wider and longer than the top.
I don't do sheets because they are woven tighter than batiks and the needle has a hard time piercing the fabric..this results in skipped stitches and the LAR is very short tempered...lol.
If flannel is used...I don't like it pre washed...After the quilt is quilted and bound,you wash the entire quilt and it does not shrink like you think it does.

Also..please remove all selvages from the seams when a back is pieced..actually remove all selvages from all pieced fabric. The reason is because the selvage is so tightly woven after washing and drying the fabric the salvege dries in a very hard line,distorts the quilt and makes a puckered look down the seam

It doesn't make any sense to me. I would ask and if I didn't agree with the answer, I would go somewhere else. I don't prewash my fabrics before I quilt. I like the crinkle look of the quilt after it is quilted and washed.