Searching the ‘net for tutorials on corner seams is the worst. Most basic seams are corner seams anyway and that’s not really what most people are looking for when they’re actually doing a search. I stumbled on a page that reminded me of this weird/tricky technique to make a corner with two different fabrics and was absolutely essential in my Beach Coat.
Please mind that my corner in this tutorial is NOT a perfect corner– but for these purposes, it’s close enough.
In order to replace a square in a piece of fabric, as above, you must cut out a square in contrasting fabric the size of the original removed square… PLUS two times the seam allowance in both directions. Why two times? Because you’ll need ONE seam allowance to insert the square on two sides— and you’ll need an additional seam allowance to keep allowances even all the way around the piece. For example, your piece has 1/2″ seam allowance. You cut out a square that’s 4×4″. The replacement square must be 5×5″ (4×4 + 1/2 SA top + 1/2 SA bottom, and then on both sides)
In the middle picture I’ve pinned the white square onto the self fabric, with right sides together, seam allowances matched up and also drawn on. It’s not necessary to mark the seam allowances— but it’s recommended to at least mark them at the intersection— this is important to know where to start and stop.
In the right image, I’ve sewn up to the corner and stopped.
At this point, it’s important to clip your corners! In the picture on the left, I did NOT clip the corners, and you can see the weird pucker it’s got going on. Clip INTO the corner on both pieces. You can see that in the center image.
Go back to your sewing machine, drop the needle down back into the point where you stopped stitching before you clipped, and you’ll be able to turn the self fabric (pivoting it, essentially) to continue sewing the new square along the seam allowance. It’ll get a little weird for the corner section, but go slow and don’t fret and it’ll be ok!
In the image in the right, I show the completed corner. As you can see, both sides are clipped and pressed.
This technique is a little tricky at first so I definitely recommend making a sample or two (or three, in my case!) before working on your actual fabric. By the time I finished the Beach Coat I had done this eight times and only then felt semi-comfortable with it.
If you have any questions, please drop them down in the comments! I’d love to hear your thoughts!