As you may have seen in my last post, I finished a UFO baby size quilt that had 2 bold colors meeting at the 45* line in 2 corners. I wanted to continue this into the binding, and finally got around to asking if anyone had a tutorial. I saw one, but it didn't specify how to make the join without a specific tool.
I'm more of the "Can this be done with a tool I have" kind of sewer, since it's not a thing I'll be doing often. I looked again online and found this video. Joyce Dean Gieszler does a good job of explaining, but specifies that she uses 2 1/4" binding, and a 7/8" square. I prefer 2 1/2" binding, so I tried a 1" square. I had another change, as well.
First, I was working with a fully trimmed quilt, so I couldn't leave the extra on the edges like she said. No problem, work with a trimmed project if that's what you have. There were no issues with this step for me.
Step 1. Prep your binding as usual. You'll need an extra 4-6" longer than usual for your top, in each color. Since mine was only 2 colors but each side was 49", I cut 3 strips of each color. The all blue and all orange corners will be a traditional miter, no special treatment. But if you want to do 4 different colors, make your pieces at least 6" longer than the side. I sewed my 3 with an angled join. pressed that seam open, and then pressed wrong sides together. The next photos are on sample fabric. The grey is actually backing from another project that still had batting attached, but it works for the demonstration.
Step 2. Mark 1/4" (or your standard binding seam allowance) on the corner, and put a pin where the dot is, to mark your start/stop point. I started the orange at the dot on the far corner, did the regular miter on the orange corner, and came to the last orange point, and stopped, and backstitched.
Start at that point to attach the blue (next color), with at least 3" off the edge. Be careful to not catch the orange in the seam, but get as close as you can and backstitch. Fold the orange up, out of the way.