Functional P100 Half Face Respirator

thingiverse

This resizes the Geminus mask for three sizes, adapting it for use as a real respirator with Honeywell cartridges that are readily available at a reasonable price through major suppliers like Grainger. To ensure proper fit, this mask must be printed in PLA due to its low temperature deformation, which allows for a precise fit. The mask size is determined by measuring the distance from the top of the nose to the bottom of the chin, not weight. After finding the best approximate fit, submerge the mask in 140F water for 30 seconds, allowing it to become pliable for about 5 seconds. Apply gentle pressure evenly across the face, paying special attention to forming a seal around the nose. Avoid applying too much force, as this can result in an unnatural fit. If the initial fitting is asymmetrical or uncomfortable, simply reheat and try again. In my experience, three people out of sixty needed around eight attempts to get it right, but they were eventually fine even with repeated thermocycling. To secure the cartridges in place, you can use hot melt glue or attach adapter plates first and then screw the cartridges into position. I plan to work on bayonet-style adapters when I have the opportunity. If there are other styles of cartridges that people would like adapters for, please let me know. Note that using three cartridges instead of two improves breathability. While Honeywell cartridges are available and easy to use, they can be restrictive in airflow. If possible, consider using Moldex cartridges for a more comfortable long-term fit. To enhance comfort, you can apply 1/2" weatherstripping around the rim of the mask, but be careful not to make the nose too tight. If this occurs, simply reheat the nose and press the mask against your face, allowing it to accommodate the padding nicely. For the bands, use 1/2 elastic or underarmor mini headbands that go side to side, not up and down or in an X pattern. The adapter plates are designed separately from the mask because the deformation during fitting can warp the threads.