Car Windows Screen Cover
Then sewed this closed with a sewing machine or by hand.
My actual screen was sewn with the machine but the sample above is done by hand.
It was only half way through the real screen that I realized the problems I was having with the bobbin were because the magnets were pulling the metal bobbin out of place. I changed to a plastic one and had no more problems.
You can not just sew straight around the bias tape because the magnets will slide along the channel and group together (did I mention these are amazingly powerful magnets for their tiny size?). I made channels for the magnets by stitching across the bias tape every time I came across another magnet.
In retrospect, I might have done better to do the second sewing by hand. Between the bobbin shifting and tangling the thread, the magnets shifting along the tape and having to change sewing direction several times for each magnet, nice quick long hand stitching might have been faster and less frustrating. If you do not have a sewing machine, you could easily stitch it all by hand.