Originally Posted by
quiltingshorttimer
Have had to take a seam in a couple of quilts I've done with wavey borders.
On a king size bargello I made for son's wedding, the borders where 10" wide and mitered (a free Jenny Beyer pattern)--she had you put all borders together first and then miter. worked fine that way. Also, borders cut from length of grain tend to stretch less---don't do many mitered borders, but any time I do borders that are 3.5" or more I always cut them length of grain--seems to help prevent waves.
I always cut mine with the straight of grain, and only the corners are mitered with any bias. I think I measured incorrectly, using the edge of the quilt, rather than the way Sprice menitioned. Thanks to everyone for thinking through so many reasons for this happening to being with, and for thinking of creative ways to correct it!