Technique for aligning quilt top and bottom when they are exactly the same
 

A lady gave me a quilt top and bottom that are made exactly the same, so quilt could be reversible. I am going to have to attach some scrap material to the backing to be able to put it on my long arm. But don't know exactly how to go about trying to match up the blocks so when it is quilted it will look okay. One thought was to sandwich it using straight pins through matching points and when aligned use a basting spray to hold in place. This is a new challenge for me.

It is darn near impossible to line them up exactly on the LA. Also the back needs to be a mirror image. IOW say the top right corner block is a star and the top left corner block is a 9P. For the quilt on the back the top right must be the 9p and the top left must be the star. If not they will never ever line up. About the only way I know of to do a double sided quilt that the back and front are the same is quilt as you go on a domestic where you are quilting one block at a time. Virtually impossible to line up on a LA rack. I would not even consider doing one unless the design was an all over E2E and even then it is very hard to get the two to line up perfectly.

Okay thanks. She may just need to settle for E2E rather than a particular pattern for each block.

I agree with feline fantastic. Pretty impossible to line up and a custom quilt would likely be “off” on the back. E2E would be my preference in this case.

E2E sounds like the solution to me, too.

Yes, E2E--Feline has given a great explanation for this reasoning. If you client doesn't understand, take a magazine and roll it up tight for her to see that the edges do not stay perfectly matched--neither will a quilt.

I agree with everyone else. It is impossible that the two will stay aligned when longarm quilting due to rolling up on the takeup bar.
I would refuse to make it a two sided quilt, but would instead agree to make two quilts from the two tops. I understand that would cost her twice as much for longarm quilting two quilts, but there's a good reason what she wants to do is seldom done.
If she really is insistent on making this two sided quilt, she should baste and hand quilt it. Just mho.

I have quilted 2 double-sided quilts on the longarm.....one was 105x115. That one did have a corner that had "grown" but it was less than 1/2 inch and the binding balanced it out. What I found important was to have the bottom (backside) border of the quilt at least an inch oversized on the side and edge of the quilt that will be the last pass of quilting. That way if you get a little movement, you can trim. I added a matching fabric strip on those edges and the little bit that it moved on that corner (so there was a scant seam where I had joined them) was hidden within the binding. E2E is the only way to go and measuring for every roll of the fabric. Loading was very time consuming....had to be just right.

Marilyn

I made a two-sided quilt. One side was square blocks and the other was randomly placed rectangles. The lady who did the long arm quilting did a rambling design that looks good on both sides. I would suggest something like that, or as others have suggested, edge to edge.