For an experiment, I drilled holes in my old and unnecessary Cara mask. I didn't like it because the air passing through these holes makes too much noise for me. So I won't be drilling holes in my beloved AirTouch F20 mask.
As soon as I spent one night with
a closed exhalation (the one on the right side in the photo), I realized that I was not getting enough oxygen and immediately ordered
a knee with an open exhalation (the one on the left side in the photo). I tried sleeping with my knee open that night but was disturbed by
a lot of noise from the air + I woke up in the middle of the night to
a hurricane in my mask. The air leakage from the open exhalation knee was too strong. I carefully read the topic and understood that there is
a seal under the plug in the knee of the closed exhalation, which prevents the air from going out. I picked it up but without the seal the air noise became unbearable. Then I guessed to install the seal from the disposable mask from the middle of my knee. And it worked, now I
have enough air flow from the mask so I don't breathe my own CO2, and I don't hear too much noise. In my personal opinion, in the knee with open exhalation (on the left in the photo), the air flow is too strong, and in the knee with closed exhalation (on the right in the photo), the air flow is too weak. With the width of
a strip from
a disposable mask, I can adjust the air flow I need. It is necessary to connect the edges of the strip in
a circle from below, where there are no holes. Because if you connect the edges of the strip where there are holes, you will hear an unpleasant squeak.
I also noticed that in the F 30 mask, the holes from the middle of the mask seemed to me to be smaller in diameter, or that mother's hole from the outside of the mask. Perhaps this structure of the hole allows you to get rid of excess noise when the air comes out.
