My conclusion. Not too hard to make. Just 3 straight lines to sew. Sounds easy right? And if you use a coupon, way cheaper than pail liners you can buy.
26 inches of PUL fabric (I found mine in the baby/ diaper section at Joann Fabrics)
36 inches of 1/4" elastic
Fabric: 5.94 (It is 14.99 regular price, so make sure you use a coupon!)
Elastic: I had this on hand, but would not be much.
1. Lay your fabric out flat with right sides together.
2. Pin down the long sides. Be careful to keep your pin holes near the outside. If you have a pin hole in the inside, it may leak. So, try to keep the pin as close to the edge as you can.
3. Sew down the sides with 1/2 inch seam allowance.
4. Measure your elastic to cut. I put mine around the outside of my pail liner to make sure that the elastic fit well. I then pinned the elastic and cut. My trash can is 12.3 gallon and I used 36 inches.
5. I then sewed where the elastic overlapped. I like to sew over this several times to make sure that it holds well.
6. Pin elastic to the top on the wrong side. I folded the elastic in half and put the folds on the seems of my bag. Pin so the elastic stays in place. The elastic will be smaller.
7. I then folded the sides in half. I pinned together the fabric and the elastic on the halfway point. The bag looks kinda messy at this point.
8. Start to sew close to the edge. See how the fabric isn't flat? Go to the next step.
9. Pull the elastic so that it is the same length as the fabric. Keep sewing. I did this for each of my sections that are a quarter of the liner.
When you are done, the top of the bag will bunch and fit nice and snug on the top of your diaper pail.
Don't want to make a pail liner? The Planet Wise Reusable Diaper Pail Liner works just as well!