Round Cartridge to 3M Adapter - Respirator

thingiverse

This allows you to keep using your old style round cartridge with respirators that are getting harder and harder to find and nearly impossible right now. This adapter enables you to fit modern 3M oval cartridges which are much cheaper and more effective anyway. It prints in two parts, the little retention stem can be super glued on, and it keeps the rubber valve in place. They have been separated to make printing easier for most people. You can take the rubber valve right off the previous setup and put it on this one, or buy a new one. I've also included an adapter that lets you use a 3M P95/N95 cotton filter with your respirator without the need for a full vapor filter cartridge. Since the current covid-19 situation isn't about vapor filtering, this is the perfect solution. You will need the 3M clear covers which are super cheap - just a couple bucks. I don't recommend printing these as they can be very difficult to remove, and it's much cheaper to buy them instead. I chose 0.1mm resolution because this is the recommended layer height to avoid tiny gaps that could hurt the effectiveness of a printed part for a respirator. PRINT THE GASKET AND SEAL IN TPU (TWO OF EACH). Supports: For the Adapter file, you will need supports from the build plate and at the top for the filter lock tabs. The inside of the model does not require supports, save yourself cleanup time and use a support blocker there. Also, save yourself a headache by only printing supports around the hole opening for the 3M N95 filter file. The rest prints perfectly fine with bridging. UPDATE: Design has been improved to make it stronger and fit the seals better. As well as making it easier to print, it's now in two pieces that will need to be super glued together afterwards. The cross hatch part with the nub goes facing inside the mask - if you do it backwards no air will flow. Do not glue that side...the sides you glue together are the ones facing the print bed. I will post updated pics soon. UPDATED: The seal has been made thinner to make it easier to use. If you find it is too thin for you, you can make it 0.25mm thicker or vice versa - it's only a small disk and very easy to modify.