How to replace a block in a finished quilt in 90 minutes or less

Last week I asked for suggestions on how to replace the bottom left block of this quilt. I got many suggestions, but the one I went with was provided by my mother, who is an experienced quiltmaker and has faced this dilemma before.

First we got out the seam rippers and took out the quilting stitches in the block and about 1 inch all around

this is my mother working in her quilting studio, unpicking stitches from the back

Then we unpicked the stitches holding in the block where it was joined by the sashing

Meanwhile, I fused the lightweight interfacing to the new t-shirt quilt block, and cut it to 13 inches square, 1/2 inch bigger than the old block

Then I marked the seam lines with a white pencil

Meanwhile, the old block is nearly out.

Here it is completely out, with the batting visible underneath. The seam allowances of the sashing are still turned under. We removed any stray threads.

Here my mother is holding up the block we removed, which belongs in another quilt. We were able to take it out without any incident, so it can be used full size. Note the lovely quilts in the background at left.

Then we took the new block and slid it in under the seam allowances, matching up the turned under sashing with the white seam lines

And then pinned it in place, placing pins every two inches to take up any ease

Next, I handstitched invisibly with a matching thread, pulling slightly with each stitch

Here it is the quilt. All it needs is quilting in the ditch and a few quilting lines to complete it.

So, if you ever find yourself with a finished quilt which has a block rotated the wrong way, or like me, the wrong block, I recommend this method. Total time from start to finish (except for the machine quilting) was 90 minutes.