Adding inserts in backing
 

I just finished the top for an I Spy quilt. II bought a solid light blue color for the backing. Then, I decided to use a darker blue for the binding (border and some accent squares are light blue w/ darker geometric pattern). As I have plenty of the darker blue, I decided to put a diagonal stripe (6" or so) on the backing. I've done the diagonal cut quilt back and like using that method. If I put the strip/stripe on the diagonal quilt, would the strip/stripe have to be cut diagonally as well?

bkay

If I understand the question, you are using what is sometimes called the Flynn method for making your yardage more square/wider by cutting on the diagonal and sliding down the pieces.

I would think that cutting the straight of grain inset would work fine if it was long enough. You might have to be careful sewing along the diagonal cut seam, so I would pin thoroughly.

If this was for garment construction, I'd probably advise to cut the bias so that everything would swirl nicely. You could cut it on bias like you were making continuous bias: cut Squares, divide on the diagonal, make a pennant (or I call it fangs) and sew the seam along the top.

Edit: I've really grown to like piecing backs. I do tend to use 1/2" seams and press open.

Thanks, Iceblossom, you understood perfectly.

For the part I said about "long enough" if your insert is cut on grain, you will have the triangular end to trim off on both ends. I think my natural (wrong-o mary lou!) reaction would be to measure the diagonal cut and use that for the length -- forgetting about the slide. No problems at all piecing the fabric for the right length either.

I would probably cut the insert on the diagonal - if i had enough fabric - so that the grains of the finished piece would all be going the same direction.

I think it would lay better.

Since this is the backing and will be quilted (as opposed to something that would hang, like a curtain) I don't think it would make any difference. I would go with a straight piece of fabric for the insert. Then I would be dealing with only one bias in each seam.