Step 1 : cut your PUL
This is a piece of leopard print knit fabric that I had PUL'd awhile ago. I had this odd shaped piece that was too narrow to make training pants with. But it was the perfect size to make a Potette bag!
First step: cut a rectangular piece of PUL. 10"x27". If you don't want a drawstring on it, then you can get away with 8-9" for the width.
Step 2 : Sew one end
Leaving about 2" unsewn at one end, fold it in half and sew one end. You can use a serger or the sewing machine. I STRONGLY recommend a teflon foot if you are sewing a lot of PUL. That puckeriness of the stitching is what it looks like if you don't use a teflon foot. I have a teflon foot for my other machine, but it was in the shop.
If you are not making a drawstring, don't leave anything open, just sew the whole side.
Step 3: Iron the seam
One nifty quality about PUL is that if you iron it, it will adhere permanently to itself. If you are putting a drawstring into it, iron the whole seam (or just the opening part if you used your serger) so it is flat. The most important part to be ironed is the open part (that makes it look like a Y)
Step 4: Pin the bottom
Fold the left side and the right side inwards, making each side look like an M. Pin the folds so it stays in place. There is no exact science to it, about 4" of folding on each side is adequate...
Step 5: Sew the bottom
I used my serger here, but you can also use your machine. Sew along the bottom to close it up so the folds stay.
Step 6: Top hem
Fold the top of the bag down about an inch. Pin it in place, and zig zag along the edge of it (PUL doesn't fray, no worries there!)
Step 7: Insert drawstring
I couldn't find our rope, so I found an old shoestring. (Note to self: go buy some rope). Turn the bag right side out. Thread your drawstring through the whole top of the bag, and tie it.
Step 8: Put it on the potty!
Here is the wet bag on top of the potty. It fits the top great, and there is no need to hook it on the potty elsewhere.