Filter Mask

thingiverse

This is a more efficient and faster build than before. It's also more comfortable for people who don't like having straps around their ears. Print two MaskInserts & MaskSnapFlannels. Other parts are optional, but they allow for more material thickness and are suitable for use with tee shirt fabric. You'll need filter material (I prefer tee shirts) and less than 30 inches of 1/4 inch elastic strap. Cut a rectangle of filter material about 25 cm x 15 cm. Fold the edges in a fan pattern, bend around the sharp edge of the insert, and hold it all in place while sliding the snap over it. If you use thicker filter material or double up with tee shirt fabric, you may need to increase the scale of the snap. Stretch the elastic to pull the mask over your head. The upper band angles high over the ears, around the back of the head, and the lower band goes below the ears, around the back of the head. Adjust the elastic through the buckles and snip off any excess. This mask seems to fit all the heads in my family, so I'll be testing it under working conditions. I've added a quick release buckle for those who don't want to mess with their hair or other personal grooming. Print two females and two males, cut the elastic straps in half, and insert the buckles at mid-point so they rest at the back of the head. The buckles are small, so I reduced the print speed to get them to come out nicely. As of 4/20/2020, paper filters work well for 1-2 hours but can degrade under heavy workload due to moisture. We've tried flannel and cotton tee shirts, and I prefer tees. However, my son complains about his breath fogging his glasses with this style of mask. To address this issue, I'll upload a clip that fastens to the outside of the filter and hugs the curve of the nose. On 4/21/2020, I uploaded the nose clip, which can be heated in shallow water for 30 seconds and bent into shape around the nose. Put the clip on the outside of the filter and insert pins to hold it in place. This design keeps the plastic away from the skin for comfort, and if the clips deform after a couple of days, simply reheat them and reshape. This design works well for various face shapes and sizes, and replacing the filter and reassembling is relatively easy. So, I'm sticking with this design for my family. As of 4/23/2020, I had one set of filter clips weaken over repeated use (including heating and reforming once). However, the clips have a limited lifespan, and I replaced the filter on my own mask about four times without any issues. On 7/13/20, this design still works great, and I use it almost daily.