3M half mask pre filter

thingiverse

I have a 3m half mask, but as everyone else I'm running low on filters. To make them last longer and improve the look of my mask, I designed a pre-filter to fit in front of it. The original 3M filter still does all the work, but the pre-filter helps keep it clean for a longer time. Since the seals on this type of attachment aren't perfect, you'll always need an original main filter installed. Before installing the pre-filter, please check your seal. Install the 603 adapter, main original filter, and dust cover on your mask. Put it on your face, then use your palms to completely cover the holes in the dust filter cover. Breathe in - if there's no leak, you're good. If there is a leak, it means you're not protected by the original main filter. This is a DIY device that hasn't been tested properly or certified. 3M's original parts are always the best choice. They did an amazing job designing the filtration system. My design is only for when you have no other option and understand the risks involved. After use, consider the pre-filter and the rest of the mask contaminated. Handle it as such. Disinfect all parts regularly - don't wash the main original filter, though. Doing so will reduce its filtering capabilities dramatically. The design is optimized for use with 2 layers of cotton t-shirt fabric, which should capture about 70% of 1 micron particles, thereby lowering filter exposure by three times. My source of information on materials and filtration is Smartairfilters.com. As a base for this design, I used the Dust Filter Cover from vyrobca. Use PETG or ABS for this one - PLA could break and leave you vulnerable. The 603 3M adapter also comes from vyrobca, or you can use an original 3M if available. You'll need an original P2/N95 or P3/N99 filter as well. The rest can be printed or found at home. Place two sheets of fabric (2 x cotton shirt piece, or similar thickness) on a flat surface. Put the pre-filter body in the center, with the slot on the bottom side. Wrap the fabric around and fasten it with the pre-filter lock. Fit it onto a Dust Filter Cover. It requires some force to fit it on, so do it while your filters are not attached to your mask to prevent damage to the connection. Depending on the fabric you use, you may need to scale PreFilterLock for a better fit. If you wish to scale PreFilterBody, be careful of uneven changes in the gap between it and Dust Filter Cover. I strongly suggest that you also install an exhaust filter so you don't spread the infection. Either the original design by alphaa or my remix, which makes it tighter, should work well. I use additional unwoven cloth between the mask and adapter for a better seal. I had to reduce supports heavily, especially for Exhaust objects and PreFilterBody. Use PETG or ABS - PLA is weak and porous. The Dust Filter Cover is crucial for the seal, so always check if it printed correctly with 100% infill. Lastly, I want to thank vyrobca and alphaa for creating such great and helpful designs. You should also check out their designs that don't need an original filter. Wish you all good health - hope this helps.