07-21-2024, 03:01 PM
Sharing my observations on refreshing old f30i masks
Hi All,
I used to do hazmat. We also use silicone masks. While we replace masks every year or so, we don't really have to. They last more or less indefinitely so long as they're taken care of. So why do CPAP masks fail? Because they're designed to from what I can tell. So I got annoyed. Thought I'd share my results to save others the effort of repeating experiments. Not positive this goes here so please move it if it doesn't.
Someone on here stated that masks could no longer be boiled because many of them now contain plastic. This is not necessarily true. I use f30i masks, which have a large plastic section. Not all plastics melt at 212F/100C. I tried boiling an old f30i. First in a baking soda only solution for about an hour, which didn't melt but also didn't make it seal again and then in a water/baking soda/dish soap solution for around 3 hours (I actually forgot about it but let's pretend I meant to do that.) Which didn't melt it but also didn't make the mask go back to sealing correctly.
Figured it couldn't hurt to try pressure cooking the mask since it already didn't work. Worst case I had some melted plastic in a steel pot that I might have to power tool out. Put it in a baking soda only solution in the instant pot for 10 minutes on manual with manual release @ 20 minutes with the pot a bit under 1/2 full. I don't know how long it will last as I only tried that yesterday, but it seals like new again. And, obviously, didn't melt. There's no visible change to it after being put in the pressure cooker. Will endeavor to post updates, including negative results.
Another thing I tried, since I mostly get leaks around the nasal area, was to reinforce that area with 00-20 silicone (super soft silicone, similar to that used in the mask, think squeezing a gummy bear.) That did work, however my nose was a bit sore in the morning, nothing too terrible but less than perfect, as the reinforcement made the mask slightly less flexible. I used 5ml (3ml wasn't enough) of 00-20 silicone and held the mask in place (upside down and tilted a bit forward) by cutting slots in the sides of a medium sized yogurt cup. While there are glues that will help silicone to stick to silicone I didn't use any, just cleaned the mask with soap, rinsed it with water, dried it and applied liquid silicone. If I was doing it again I'd pressure cook it in baking soda and just rinse it off with water as I think the soap may have formed a film that interfered with the bond between old and new silicone. In my case that was actually a good thing as it makes it possible to pull the new silicone out and try again or just pressure cook the mask instead. Would probably last about a week if I kept using it before the new silicone falls out. If pressure cooking doesn't continue to work I'll revisit this, maybe try to find some silicone even softer than 00-20 or just try to apply the silicone to the inner part of the nasal channel rather than filling the whole thing so it's a bit more flexible.
My next idea, depending on how long a pressure cooked mask lasts, is to use an oven at various temperatures. Since I'm concerned about that melting the plastic the thought was to take a deepish loaf pan, fill it with water, and position the mask such that only the silicone nasal portion is above the water line. Then bake at temperatures starting around 250F to see if I can get the same shrinking effect people get with their silicone phone cases but just on the nasal area that's leaking. So long as the plastic part of the mask is below water it will never exceed the boiling point of water, but the nasal portion that's above water should be closer to the temperature of the oven. Positioning would be a challenge and I planned to hold the mask in place with 3d printed supports using magnets adhered to the bread pan, though a similar effect could probably be attained by running thin metal wire (solid stripped ethernet wire or just fishing line if it can stand being boiled) through the exhaust holes in the mask and attaching that to weights if you want to try this and don't have a 3d printer. The same idea could be done with a heat gun (or a torch if you're more confident than I am) in case the boiling water in the oven lowers oven temps too much. That would take a bit more finesse and might produce less reliable results. Still, if the mask is trash anyway may be worth a go. Again, haven't tried this, it was just the next idea.
Another thought is to use the glue (I think spirit gum) used in costuming around problem areas before bed. Which is likely a lot cheaper than buying a new mask each month, given how little of that glue would be required for just the nose or just contact area around the cheeks/chin or wherever your mask leaks when it fails. Haven't tried that and no idea how hard it is on the skin. Would make removing the mask at night a real pain. Personally I drink through a ptfe tube I shove up under the bottom of the mask so as not to take it off, but if you do remove yours it'd be a pain.
Anyone have anything that works better for them than the ideas I've listed here?
I used to do hazmat. We also use silicone masks. While we replace masks every year or so, we don't really have to. They last more or less indefinitely so long as they're taken care of. So why do CPAP masks fail? Because they're designed to from what I can tell. So I got annoyed. Thought I'd share my results to save others the effort of repeating experiments. Not positive this goes here so please move it if it doesn't.
Someone on here stated that masks could no longer be boiled because many of them now contain plastic. This is not necessarily true. I use f30i masks, which have a large plastic section. Not all plastics melt at 212F/100C. I tried boiling an old f30i. First in a baking soda only solution for about an hour, which didn't melt but also didn't make it seal again and then in a water/baking soda/dish soap solution for around 3 hours (I actually forgot about it but let's pretend I meant to do that.) Which didn't melt it but also didn't make the mask go back to sealing correctly.
Figured it couldn't hurt to try pressure cooking the mask since it already didn't work. Worst case I had some melted plastic in a steel pot that I might have to power tool out. Put it in a baking soda only solution in the instant pot for 10 minutes on manual with manual release @ 20 minutes with the pot a bit under 1/2 full. I don't know how long it will last as I only tried that yesterday, but it seals like new again. And, obviously, didn't melt. There's no visible change to it after being put in the pressure cooker. Will endeavor to post updates, including negative results.
Another thing I tried, since I mostly get leaks around the nasal area, was to reinforce that area with 00-20 silicone (super soft silicone, similar to that used in the mask, think squeezing a gummy bear.) That did work, however my nose was a bit sore in the morning, nothing too terrible but less than perfect, as the reinforcement made the mask slightly less flexible. I used 5ml (3ml wasn't enough) of 00-20 silicone and held the mask in place (upside down and tilted a bit forward) by cutting slots in the sides of a medium sized yogurt cup. While there are glues that will help silicone to stick to silicone I didn't use any, just cleaned the mask with soap, rinsed it with water, dried it and applied liquid silicone. If I was doing it again I'd pressure cook it in baking soda and just rinse it off with water as I think the soap may have formed a film that interfered with the bond between old and new silicone. In my case that was actually a good thing as it makes it possible to pull the new silicone out and try again or just pressure cook the mask instead. Would probably last about a week if I kept using it before the new silicone falls out. If pressure cooking doesn't continue to work I'll revisit this, maybe try to find some silicone even softer than 00-20 or just try to apply the silicone to the inner part of the nasal channel rather than filling the whole thing so it's a bit more flexible.
My next idea, depending on how long a pressure cooked mask lasts, is to use an oven at various temperatures. Since I'm concerned about that melting the plastic the thought was to take a deepish loaf pan, fill it with water, and position the mask such that only the silicone nasal portion is above the water line. Then bake at temperatures starting around 250F to see if I can get the same shrinking effect people get with their silicone phone cases but just on the nasal area that's leaking. So long as the plastic part of the mask is below water it will never exceed the boiling point of water, but the nasal portion that's above water should be closer to the temperature of the oven. Positioning would be a challenge and I planned to hold the mask in place with 3d printed supports using magnets adhered to the bread pan, though a similar effect could probably be attained by running thin metal wire (solid stripped ethernet wire or just fishing line if it can stand being boiled) through the exhaust holes in the mask and attaching that to weights if you want to try this and don't have a 3d printer. The same idea could be done with a heat gun (or a torch if you're more confident than I am) in case the boiling water in the oven lowers oven temps too much. That would take a bit more finesse and might produce less reliable results. Still, if the mask is trash anyway may be worth a go. Again, haven't tried this, it was just the next idea.
Another thought is to use the glue (I think spirit gum) used in costuming around problem areas before bed. Which is likely a lot cheaper than buying a new mask each month, given how little of that glue would be required for just the nose or just contact area around the cheeks/chin or wherever your mask leaks when it fails. Haven't tried that and no idea how hard it is on the skin. Would make removing the mask at night a real pain. Personally I drink through a ptfe tube I shove up under the bottom of the mask so as not to take it off, but if you do remove yours it'd be a pain.
Anyone have anything that works better for them than the ideas I've listed here?
