I cut my pieces though a bit bigger. I cut 4 pieces the long length at 18.5x 5 1/4 and the short length I cut 4 12.5x5 1/4 and the bottom I just cut the half inch seam allowance. The reason I make the height bigger is for the binding and trying to get the box around your machine. I ONLY hand stitch binding. :)
Once my pieces were cut I went and got my left over batting and matched them up and am ready to quilt. I did use decorator fabric and still quilted it because you want the stiffness come batting time.
Then I quilt on a diagonal line. If you are perticular you could use masking tape to help. I just eye it up. I don't use anything on the back. It's just fabric and the batting. That's what the picture below is showing you.
Once you have quilted all your pieces cut the excess batting off.
Now I have two sets of the same pieces. 4 long length, 4 short length, and 2 bottom pieces. You could obviously use cordinating fabrics I just didn't.
You take a long and a short side and facing each other you sew them together.
Once sew they will look like this. Reapeat this step so that you have a long touching a short and then another long touching another short. See picture below.
So that it will look like this when you are done. It will take on the shape of your box.
Then you pin the bottom like so and sew it and continue around until...
it looks like this. Do this with both sets that you have for your box.
The picture below is supposed to show you one box is inside out and one is right side in. One is for the outside of the box and the other is for the inside. You see where I'm going. Right:)
Then you start putting it together.
One on the outside and one on the inside. The inside one will seem bunchy. That's okay.
Make your binding. I cut 2 1/4. You could do 2 1/2. It's up to you.
Start in the middle of one the longer sides and put the binding around. I fit the binding first...
Then cut the 1/4 inch...
Then I take it off and sew it. Wow I'm sure you really needed to see this picture:):)
I finger press the seam.
Now your binding is a circle.
Put it back on your box and...
pin it all the way around.
This can be the tricky part. Sewing on the binding. But it you give yourself that bigger allowance and pin it - it's not so bad.