I trimmed the top and right side lime borders on quilt top and then applied the mango borders to those sides.
Then I auditioned the avocado border pieces on the design wall. I wanted the border to also have the tapered string look of the small "windows", but the outside of the finished quilt would have to be on the straight of grain. This meant that the inside seam would be on the bias. Here's how I did it...
I placed the border along a horizontal measuring line on the cutting board to keep it straight and then I placed the quilt top over it and overlapped them at the border. I made sure that the quilt was also on vertical measuring lines. This will make more sense when you see the next photos...
In this photo, the quilt overlaps the border by a few inches. In order to get the border on straight, I had to make sure that the border and quilt were at perfect 90 degree angles.
Once I knew that the pieces were straight, I used a couple of rulers to make a slight diagonal cut in the overlapping sections. And here's the result:
...a slightly tapered inner border, with a straight-of-grain outer border. As most quilters know, a bias edge outer border is a nightmare to quilt because it will stretch from here to St. Louis.
Whew! Okay, now the borders were on and they needed to be squared. I placed two sides on the cutting board lines (left and right) and laid out three square rulers along the top. Cutting along the edge of the flush rulers gave me a nice straight edge.
Be sure to always square each of the blocks in a quilt, then square the center of your pieced quilt, then square the quilt with the borders on. It's the only way to get a nice square quilt, which will save you hours of headaches as you quilt it.
I'm not totally thrilled with my sashing...it's not all perfect...but I'm happy with the finished product. Voila!