1. Linen fabric (for outer bag and strap)
2. Lining fabric (for inner bag)
3. Non-fusible woven interfacing
Making a Water Bottle Bag Step by Step
Now, you should have two fabric tubes as shown in the photo.
After that, pin the round lining fabric that you made onto the bottom of the lining fabric tube as shown in the photo and sew along the round edge. Repeat this step for the outer fabric tube. Once you have finished sewing the two bases, turn the outer bag right side out. Automatically, the inner bag will be fit into the outer bag.
Lastly, make a long shoulder strap with the linen fabric. The length of the strap would be your desired measurement. Align the top edges properly and pin each end of the strap between the layers at the appropriate position. Sew the top edges together with a 0.2cm seam and sew a triangle at where you inserted the strap ends.
A simple water bottle bag is done.