Which materials should you choose?

There are a few  things to consider:

• Firstly, what do you already own? Taking unneccessary trips to the store is not the aim.

If you look at the ranking (here) of different materials you will find that tightly woven cotton (pillow cases, cotton popeline, etc) and vacuum cleaner bags are your ideal candidates for DIY mask making. I would advise against dish towels because it will get unneccessary bulky and hard to breath through. I prepared a handy chart for you to make your decision as clear and easy as possible.

• Secondly, the theorie around how a mask is constructed. As you might have already read (here) there is no functional use of double layers. Which is actually great, because it means that you can choose your inner layer for comfort, while the outer layer is for function. I would recommend using a layer of viscose because it's light and breathable and soft against your skin. A cut up T-shirt will work as well, but will be way hotter (summer is approaching..) and thicker. As you will ideally also use a filter material, it might get a bit thick and hard to breath through.
• Your layers will be: 
• outside: cotton fabric
• filter: optional but highly recommended
• inside: soft viscose challis
• -> to simplify the mathematics: only the layer with the highest percentage counts (in the example the vacuum bag material wins out)
• Important: Only use natural fibers! They will be able to withstand the highest temperature of your washing maschine without shrinking. Artificial fibers are also a breading ground for bacteria and don't absorb moisture, which will be very uncomfortable to wear.

• BTW: you don't need to worry about the vacuum cleaner bags disintegrating in the wash. I tested them thoroughly (soaked them in cold and hot water over night and even boiled them in hot water to see it they would dissolve.) They will hold up :)

• If you look at how a real FFP mask is constructed you will see that the main point of importance is the nose. Namely that no air gets in or out around your nose (the fit everywhere else is easy to achieve).

As you can see the mask is tapered in at the nose

There is a wire to form it to your individual measurements

And there is a spongy rectangle for tightness (and comfort?)

So what we are aiming to recreate is a mask with optimum fit and from the ideal material (that you already have at home or can order online)

Jump to the handy flow chart!