This is a post for Isabel. She likes the masks I recently sent her along with some fabric to make her own, so this is a step-by-step lesson aimed at her. If anyone else finds it useful, that's great.
1. Cut out the pattern. I use this one. It fits me exceptionally well. The 3/8" seam allowances are included.
2. Trace the pattern onto your pre-washed batik fabric (it's the densest cotton) using tailor's chalk and cut out three pieces from doubled fabric. You will end up with six pieces in total (each piece below is actually two pieces). I like to make one set out of a contrasting lighter fabric that will become the lining.
3. Sew the long curved edges, then clip the curves.
4. Press the pieces open with the seams to one side. Press the seams in each piece in the same direction. It will all work out, trust me. Then layer them in this order.
5. Pin the layers together and sew the top and bottom. The top is the longer curve. It's pretty obvious.
6. Turn right side out so that the right side of the lining is showing. At first you'll think there's no way this will fit through the side openings, but struggle for a minute and suddenly it'll go. Press everything nice and flat.
7. Edgestitch the bottom. If you wear glasses all the time, go ahead and edgestitch the top. Your glasses will shape the top edge around your nose.
8. If you don't usually wear your mask with glasses, you can insert something like this.
This is the plastic-covered piece of metal (I assume it's metal) from the Stonemill bread I buy at Loblaw. It's perfect for this purpose. Insert it into the top edge and edgestitch as shown below.
9. Turn the side edges under about 1/4", then about 3/8". No need to be precise. Edgestitch in place, backstitching a few times at the beginning and end where the elastic will put some strain on things.
10. Cut lengths of elastic. I use special mask elastic that I purchased from Fabrications. I cut 9" lengths because the elastic will shrink after washing. I use a blunt tapestry needle to thread through the side edges. You could use a small safety pin if your side openings aren't too narrow.
11. Tie off the ends. I recommend washing the mask before wearing. Everything will shrink a little, which for me results in the perfect fit.