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Thread: Rental masks are crap. How can we do better?

  1. #1
    pewpewpew vijil's Avatar
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    Rental masks are crap. How can we do better?

    My local field use Switch FS masks with thermal lenses. When they get moisture between the panes (which they all do), they fog up in use. The fog can't be wiped off, meaning the punters are just having to put up with it. It's the #1 complaint I hear from punters about their day playing. Not the pain, not the money, the masks.

    I had the same problem with my (brand new) vents lens, so I put it in a hot water cupboard overnight to get the remaining moisture out, then superglued the seal all around. I also sealed up using blutack where the bridge of the nose joined the goggle part. So after a bunch of warranty-busting I ended up with a mask that's very fog proof compared to most. Even on hot humid days in the bush after rainfall it's never given me issues.

    I've suggested that course of action to the local field, however I have to ask - why is this a problem in the first place? The issue seems to be that the lenses aren't actually sealed and the thin foam used isn't keeping moisture out. Sometimes we even see paint getting between them.

    Can somebody in the know explain why the lenses aren't just airtight sealed from the factory? Perhaps with a plastic welded or glued plastic gasket rather than the foam? Is there an air pressure issue for air frieght? Or is it just difficult/expensive?

    I bring this up because, again, it's the #1 complaint here and probably a huge turnoff for potential repeat customers.

    That and the foam gets gross. Maybe it should be sealed/covered with something you can just wipe to clean.
    https://www.instagram.com/vijil/
    I draw guns and spaceships and bunnies

  2. #2
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    Polycarbonate has a high moisture vapor transmission rate. You can't really seal it. You need to vent it.

    The best solution would be a snap in gasket full of desiccant that can be regenerated in any oven before play

  3. #3
    pewpewpew vijil's Avatar
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    So I had no idea that water can get through plastic. That's interesting.

    I take it there isn't much in the way of good alternatives that aren't glass.
    https://www.instagram.com/vijil/
    I draw guns and spaceships and bunnies

  4. #4
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    There's something like aclar which has insanely low mvtr but the desiccant is a much better engineering solution. I think it would work great in this application. Generally the dew point would be at zero degrees. It only takes something like 90c to recharge a silica desiccant.

    All polymers have nonzero permeation to all gas solutes. There's some interesting games to be played with the thermodynamics of it.

  5. #5
    pewpewpew vijil's Avatar
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    So you're suggesting a mask with a double strip gasket - probably the outside one being much the same and venting as they currently are, while the inside line is a dessicant. Throw the whole lens in the oven to reset. It would be interesting to see how often you'd need to do that (you'd hope that without baking it would perform much the same as any other thermal lens)

    I've often also wondered about the potential of superhydrophobic (nanomarketingBS) coatings, though most antifog is instead hydrophilic. Could antifog coatings between panes help? They'd last a while.
    https://www.instagram.com/vijil/
    I draw guns and spaceships and bunnies

  6. #6
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    Philic coating would help, yea. There still isn't a perfect solution for that, though because water has such high cohesion and surface tension (contact angle, or film spreading, is a 3 phase energetics problem). That's why the scuba solution is soap - surfactant changes the surface tension and acts on the condensate itself, rather different than what any solid coating can do.

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