I’m not sure I’ve ever felt the need to start an article with a disclaimer, but I do today. Pandemics and viral infections are deadly serious, and I lay no claim to being any sort of expert in how to protect myself (or you) from airborne, or otherwise, virus. I do know enough to know when it’s time to seek out superior wisdom though, as should you. In this case, I looked here for design input on how to make a mask, and here for information about what fabrics are actually useful for the purpose of personal protection. The latter source is comprehensive, but the takeaway is that a 100% cotton t-shirt is an acceptable compromise between stopping virus and allowing you to breathe (both factors are important).
Given that a t-shirt is the most acceptable and available fabric to make a mask from, I dug out a white Uniqlo t-shirt in quite a heavy fabric. White tees are stain-magnets, so it’s not uncommon to have one available for upcycling. One size large should make about 8 face masks, so it’s good value. And that’s really all you need, apart from a sewing machine and some thread. You could even hand sew them at a pinch.
To get the elastic or strips of fabric through you can use a safety pin, or darning needle (easiest). Once threaded through, check mask for fit and adjust fastenings for size. Sew or tie them in place and hide the splice inside the seam for comfort and tidiness. And you’re all done!
Now, that was making one from t-shirt alone. As shown by science, a single layer of t-shirt gives almost as much protection as a double layer, so there isn’t much gain in going the extra mile and doubling up. The extra mile though, that is what we do around these parts, so I couldn’t help myself from making a second mask. For this one, I added a layer of tweed for a more swaggy look. You could do the same with other fabrics, but it’s a good idea to test whether you can breathe through it first.
To do this I cut a square of tweed the same size as the t-shirt (I added a cm to make it 23x22cm,), laid one on top of the other and sewed almost all round the edge, leaving a gap so it could be turned inside out.