Functional P100 Half Face Respirator

thingiverse

This resizes the Geminus mask for three sizes and adapts it for use as a real respirator with Honeywell cartridges. These cartridges are currently fairly available and are reasonably priced through most major suppliers like Grainger. This MUST be printed in PLA for proper use as the low temperature deformation of PLA is required for fitting. The mask size is based upon the distance from the top of the nose to the bottom of the chin and does not correlate with weight. After finding the best approximate fit, dip the mask in 140F water for 30 seconds. This gives approximately 5 seconds of pliability in which it can be molded to the face. Attention is needed to apply force evenly across the face and in particular to forming the seal around the nose. Pressure needs to be applied gently as a forceful reshaping will result in a mask with an unnatural fit. If the initial fitting is asymmetric or uncomfortable simply reheat and try again. In the 60 masks I have made, three people needed around 8 attempts to get it right but they were ultimately fine even with repeated thermocycling. The cartridges can be fixed in place directly with HOT melt hot glue or by gluing the adapter plates in place and then screwing the cartridges in place. I will work on bayonet style adapters when I get a chance. If there are other styles of cartridge that people want adapters for, please let me know. Note: Three cartridges are used rather than 2 to improve the breathability. Honeywell cartridges are tiny and are more restrictive in air flow than any other brand but they are the most available. If they are available I recommend the Moldex cartridges. For a more comfortable long term fit, the thinnest 1/2" weather stripping can be applied to the rim but this often results in the nose being too tight. If that happens the nose can be reheated and once tat mask is pressed to your face, the nose will accommodate the padding nicely. I recommend 1/2 elastic for the bands or underarmor mini headbands. The bands must go side to side not up and down or in an X. The adapter plates are not integrated with the mask because the deformation when fitting the mask warps the threads.