These fabulous instructions were put together by Trista of Olive Branch Baby – Thank you Trista!
Cut your layer(s) for the cover as you normally would. Here I’m making a single-layer windpro cover.
Lay some scrap under the side of the leg opening. You will cut one edge along the curve of the leg opening, and the other edge will be straight. Use a ruler and make the straight edge reach about a half inch past the elastic stretch point on the top and bottom. These are your gusset pieces. If your body has 2 layers, so would your pieces.
See above how the gusset piece goes a little past the teensy blue dots that are my elastic stretch points.
Now you’ll apply fold-over elastic (FOE) to the straight edges of the gusset pieces. I like to use a size smaller than what you’ll use on the cover body, so here I used 5/8″on the gusset pieces. Give it a good stretch as you sew it on.
Now to apply the gusset to the cover is a bit tricky. Line the upper edge of the piece with the edge of the leg opening, wrong sides together. The top of the elastic edge of the piece should align with the elastic stretch point on the body or be just a bit under it. See the angle of the piece in the picture, it’s perpendicular to the diaper body. Sort of.
Now you will sew the piece onto the cover. Start where you pinned it on the end, and go slowly, continuing to match up the edges as you go. Do a little at a time, match the edge, sew, match the edge, sew. Pinning doesn’t really help; it’s easiest to do it with your fingers. I used a regular straight stitch. You want a small seam allowance here, so sew close to the edge.
See how I am matching up the edge?
You’re almost done! See the pretty gussets!
Now you will sew on your fold-over elastic. You’ll do this just as you normally would. When you get to the gusset, that’s when you’ll be stretching the fold-over elastic, so go slow and make sure the gusset and everything gets inside the fold-over elastic.
See how I’m getting everything into the fold-over elastic?
You’re all done! Look at that purdy gusset!