Diagonal Pieced Back -- Success!!

A few years ago I took a class with John Flynn.  And even though the class was on hand quilting, he gave us a handout for how to extend a single piece of fabric when you don't have enough to piece two vertical or horizontal segments together for a back.  I seem to remember seeing him demonstrate this on TV, too -- maybe on Simply Quilts.

I kept the handout, intending to try it someday.  And the day finally arrived.  My quilt, "Sand and Surf" (a/k/a Bob and Weave) is 40" x 53".  For the back I would need at least 48" x  59".   The fabric I wanted to use for the back was 41" x 80" (after cutting off the selvage for a friend who collects them) .  What's a girl to do?

Even though it was on my design wall in late October, I was having trouble understanding the formula and the drawing.  I decided this week's guild retreat would be a perfect place to spread this out and enlist the aid of some math-wizard friends.  Success!!

Sand and Surf on Diagonal-Pieced Back

First I'll give you my definitions of the unknowns in the formula:

Wq = Minimum width required for the quilt back (quilt width plus extra for quilt frame)
Wf = Existing width of the quilt back fabric
Lq = Desired length of the quilt back (quilt length plus extra for quilt frame)
Lf = Minimum length of quilt back fabric required

You can tell by our messy worksheet that we were struggling to put the right numbers in the right places.

Once we determined that we needed a piece of fabric a little under 2 feet long, we rounded that number up to 72 inches and cut the length.


The next step is to cut the back on the diagonal from corner to corner.  Donna says, "The easiest way to mark for cutting would be to snap a chalk line."  Doh.  We're at a retreat, Donna.  So we substituted a long tape measure for the chalk line and drew a line along that.

Donna marking the diagonal cutting line

BTW, isn't this a great retreat space?  It was late at night so the room is kinda empty.  Anyway, I cut along the line.

Libby cutting the diagonal

The next step is to slide the left side (from where I'm standing) up along the diagonal until you reach the desired width.  We had taped a tape measure along the edge of the table so we'd know when we hit the magic mark.  We marked and cut off the points that extended above and below the top and bottom edges and that's all the waste we had.

The last step is sewing the seam and pressing.  John recommends a 1/2" seam, so that's what I did.

Finished Diagonal Pieced Back

And that's my little tutorial for the day.  I hope you will try it.  You can always contact me if you have questions.

Linking up with Sara at Whoop Whoop Fridays.


To print your own copy of his technique for a diagonal-pieced back, go to John's website.  John states that this is the most efficient way to make the back whenever the needed width of the quilt back is no more that one and a half times the width of the back fabric on hand.  It saves fabric and instead of having a straight seam with the bulk of the seam allowance all in the same spot as everything rolls up, the seam allowance rolls up diagonally along the back.