The Spencer Sphere: Seat Cushion Cover Tutorial

Buy foam and cut into desired size. I'm making a window seat cushion, my piece of foam is 2' x 5' x 2".

Lay foam on the wrong side of the fabric and draw around the foam, use a pen or chalk that wont show through the fabric. I used a yellow marker, I could kinda see in on the other side. You will add side length and seam allowance when you're cutting.

Using my rotary cutter I measured half the width + seam allowance away from the foam line (drawn in yellow) and cut. My foam is two inches thick and I'm giving myself 1/2 inch seam allowance. So I cut 1.5 inches from the yellow foam line.

Then I mitered the corners. I folded each corner into a 45 degree angle and sewed a line 90 degrees from the yellow foam line.

I hate zippers, and every time I put one in I have to re-learn how to. So this is how I do zippers, but if you have a better way -- use it. I laid down my zipper and pinned the fabric where the zipper began and ended.

I sewed between the pins using a basting stitch. I then picked every third stitch so it would come undone easily.

I pressed open the fabric from where I just sewed and laid my zipper on the inside.

I pinned it in place, and used my machine's zipper foot to sew it in place. I back-stitched at the beginning and end.

Next I zipped it closed. Flipped the fabric completely over so the right side was up and started sewing the other side in place. You may want to place a few pins to keep everything in place. I had to unzip the zipper to sew at the very top of the zipper tape.

I then pulled the seam apart, here's where the picked stitches come in handy. That's how I put in my invisible zipper.

Finally, I pinned the whole thing together, pinning the corners first and working towards the middle, and sewed it together. Remember to open the zipper a little before sewing, so you can easily turn it inside out. And TA-DA a seat cover.