Boxing Bag Corners
To box the corner of a bag you're going to line up your side seam and your bottom seam and pin those so that those seams are aligned, Next you're going to use a ruler with a 45 degree mark on it, in this case I'm going to make a line 1 ? inches down and you'll see I've lined that 45 degree mark up at the side fold here and I'm just going to mark across so we're marking an inch and half up from the corner and it's going to be a three inch line that I've marked. Then I'm going to sew on that line and trim off the excess right here and that's all there is to it. So now you see that's what a boxed corner looks like and it's going to give you the depth to the bag and a little more structure to the bag.