Fog-Free Mask Hack Solves Mask Versus Glasses Conundrum With Superb Seal

If you have worn a mask and glasses together for more than a quarter of a second, you are probably annoyed that we don’t have a magical solution for foggy lenses. Moisture-laden air is also a good indicator of where unfiltered air is escaping. Most masks have some flexible metal across the nose bridge that is supposed to seal the top, but it is woefully inadequate. The Badger Seal by [David Rothamer] and [Scott Sanders] from the University of Wisconsin-Madison College of Engineering is free to copy during the COVID-19 pandemic, even commercially. It works by running an elastic cord below the jaw and a formable wire over the nose to encourage contact all around both mouth and nose.

You can build your own in three ways. Each configuration is uniquely suited to a different situation. The first design is the easiest to make and should work for most people. The second is best for folks who need a better seal on the lower half of their face, like someone sporting a beard. It can also have ear loops, and that means your 3D printed ear savers have another use. The Madison campus of the University of Wisconsin also has fun with lock cracking and graphene experiments.


Badger Seal takes its name from [Bucky Badger], the school’s mascot. There was no animal testing for this project, but if you can fit a mask on a badger’s face, you can name it whatever you want.

Thank you for the tip, [cyberlass]

35 thoughts on “Fog-Free Mask Hack Solves Mask Versus Glasses Conundrum With Superb Seal

  1. Maybe this is just the shape of my face, but I put on a paper mask with wire at top, as supplied by my company, bend the wire to fit my nose, then sit my glasses on top of the mask, just over the edge. The mask stays put and doesn’t vent upwards. I work with all these people who after ten seconds of talking their masks drop down below their noses and they have to keep pushing them up. The only person I’ve convinced to try the glasses-on-mask thing was all “hey this works great I wish I’d tried this a month ago.” But he has a somewhat similar shaped face to mine. It’s possible people with very little bridge to their noses wouldn’t do well with it, I’m not sure.

    1. Odd, I have the opposite problem (as does the polystrene head in the thumbnail) that my masks ride up and press against the bottom of my eyeball. A sensation I abhor.
      This device might be an answer to that.

    2. Depends greatly on the size and shape of the eyeglasses frame. This method works with the shape of my sunglasses, but with my normal glasses, the mask forces them farther away from my face, which negatively alters the focus.

    1. Makes sense based on my experience.

      I use a large cotton bandana (with lots of stray fibres in the weave), folded in half diagonally to form a triangle, then tied around at the back of the neck, a la stage-coach-robber. I like the larger filter area, for reduced velocity for a greater dwell. (The part that hangs down over the face to one’s chest can also be tucked into the top of one’s shirt.) This had some fogging of glasses, sometimes mild, sometimes severe.

      So I tried folding the top/long edge over 1/2″ a few times first. Seems that’s dense enough to prevent airflow through the folded portion and thick enough it acts like a gasket against the face, as now there’s no fogging.

      So I’d guess you’re getting a same/similar effect due to the density of the seams along the top?

  2. Many/most disposable masks have elastic ear loops to hold the mask against the face. They also tend to have a malleable wire already built-in at the top. The idea is, the wearer folds the mask in half to mark/pinch the nose portion and then bends out the sides to allow the mask to be placed. The better disposable masks have the nose-wire area already attached with a piece of non-adhesive “tape” which is “pused” up against the face to help cut down on the “fog”.

    Real surgical masks have a tie that goes over the head and a separate tie for the back of the neck. Similarly, these masks have a wire and typically the non-adhesive tape or some other means of reducing/eliminating the fog effect. On my masks, I use 3M Transpore tape to seal the area above the nose and side to side under the eyes (basically one piece of tape almost from ear to ear across the bridge of the nose and pushed down under the eyes). Naturally, surgical masks are not appropriate for everyday use outside the operating room.

    As a last resort, goggles are available on which drops of anti-fog solution can be applied prior to surgery to avoid the fog effect (same stuff scuba divers use on their masks). Spit can work in a pinch.

    3M Transpore Tape …

    1. +1. FINALLY. Often it’s a mix of miscable mineral oil and aloe or the hand lotion that used to be found w lanolin.. starts w a G methinks. Brain dead tonight. Is also in said stuff for motorcycle riders shields and anti-windshield fog lotion / towelettes. Spit or 1890’s rocket science. Choose.

  3. I made a 3D printed plastic nose strip, carefully fitted to my nose bridge (it took seven prototypes), and glued it instead of the metal strip on the cheap eBay KN95. It feels like it eliminated most upward leakage. I then cut the ear loops and joined them with rubber bands behind the head for a tight fit without ear pressure. That improved the fit even more. Finally, I put a 3D printed buckle on the lower strap for ease of putting on. It’s a fair amount of work per mask, but I reuse them on a weekly schedule (letting time do the disinfecting), and it now feels like there is no leakage (but I don’t have the equipment to test).
    When I really want to be safe, I wear an N100 or P100 respirator (with valve covered). But I am a lot easier to hear in the KN95s, so I use them when teaching.

    1. [apologies for the hijack, but the exhaust port filter reminded me of this, which might be useful to others]

      I bought 3M 61/62/6300 half-face respirators for an upcoming airline trip. To filter the exhaust port, I found these on Thingiverse, printed a couple of them, and can verify that they are a perfect fit and work well. I use 2″ circles cut from a disposable surgical mask in the filter.

  4. My glasses fogging up is my pet peeve with the mask thing. Another peeve is the ear loops of any mask wanting to pull off my hearing aids every time I pull them off in un-needed areas. going to try a 3d print to make my glasses arms take the place of my ears and see what that does for me.

  5. Rub a thin film of liquid dishwashing soap on both sides of lenses. Takes just a drop worth. Let dry. Buff to clear using tissue. Reapply as needed. A great anti-fogging treatment.

    1. Be careful with Dawn(TM) dishwashing liquid if you have metal frames, it could dissolve them over time.
      (This from my S-i-L who nearly lost the setting of her engagement/wedding ring as the prongs weakened.)

  6. The idea that people should be homebrewing or buying unrated commercial masks is now absurd. It was fine 3 months in but we’re now most of the year into the pandemic and *still* production of actual effective masks hasn’t been increased. We need Ameritech and 3M getting 10+ year government contracts to make proper N95 and normal people getting them in addition to health workers; not all this.

    Yeah, this particular modification is great and it is needed for the masks to be effective in protecting you. It’s not just about glasses fogging. But we shouldn’t have to do this. This is serious, life risking stuff. We don’t make our own seatbelts, we should not be making our own masks.

      1. “We need certified masks not those Chinese made ones[…]”

        In addition to homemade masks, I’ve bought Vietnamese masks, I refuse to buy one from the country that “gave” us this virus.
        Having China profit from the damage they caused is one step further than I’m willing to take.

        I’ve also cut back my Banggood purchases as well.

    1. This seems exactly right, though I suspect that N95s are primarily designed for protecting the wearer rather than others. I expect you will generally get a better seal to the face at inhalation than at exhalation. So some modification for better two-way protection may still be called for, especially in cases where one is breathing hard, say during physical exercise.

      1. This ^^^^

        These masks are for protecting the wearer, not those around them. They were never designed to filter exhaled air/droplets (and in fact, most quality masks have an bypass exhalation valve for this very reason.)

        1. BTW, I’ve always wondered if the exhale valve isn’t a weak point in the protection of the wearer? I would expect that some contaminants will enter as the valve diaphragm switches from open (exhale) to closed (inhale). Maybe it’s not an issue, since the first part of the inhale cycle will mainly pull in air that has just been exhaled, and that is the part of the cycle that will close the valve? I guess this is all part of the 0.03% pass-through rate of an N100/P100 mask?

    1. I recognize that configuration from another product. Any excuse to buy donuts is good. The double wire bag closure is visible in this link. It must be a fairly commonly used device.

      The wire in disposable masks does not hold its shape well enough to create a seal on my face. I cut one apart the other day and found it to be a “twist tie” like one would find managing a cable on a new electronic device of pretty much any sort. Two things work against it: 1-the plastic on the outside of the wire is always trying to straighten it out so it doesn’t stay contoured to my face, and 2-the pressure from the elastic ear loops is also trying to straighten it out.

      I’m not actually into customizing disposable masks, but for the first time in my life I seriously considered getting contact lenses. When working in a 65F server room, I just have to take my glasses off. Fortunately, I can still see the screen well enough to get by for quick stuff, and I’m usually in there by myself so can take off my mask and leave my glasses on if I have to really see detail on the screen.

      I have wondered if a custom die in a small press with heat-setting capability might properly press and subsequently hold the shape of the twisty-tie inside a disposable mask. I’m banking on the pandemic to be over before I get around to testing that concept.

      Maybe just a boat load of little white donuts and some VHB can solve my disposable mask woes.

    2. Hacker fuel. Whole bean or ground, coffee in those foil bags comes with a stiff band like we’re on to here. I just cut the whole top of the bag off and dump the whole beans into the daily grinder.

      I have been using a N95 cup formed mask, repaired with elastic cord. The rubber bands break at the staple. While grungy it’s comfortable in public as it’s fits like an old pair of shoes. I will save and try the stiffer band, but if I fit it good no fog. The baby shampoo trick might be useful in the winter with regular glasses.

      1. in regards to “grungy”

        I’ve machine washed a few N95 masks to get a few more uses out of them.
        (I use one of those zippered mesh bags to keep the elastic/rubber bands from tangling with other clothes and the agitator.)

  7. Wow. I’m impressed. The dedication it must have taken to get the fog tube to come out of the person’s mouth without running over the facial area disturbing the seal. I wonder if it was done pre or post-mortem. It kind of reminds me of Jeepers Creepers.

  8. You know…. If you shape the metal wire in your mask to the shape of the part of the face it sits on, the bridge of the nose and the cheek bone area, you can achieve a good seal. I have to wear safety glasses at work and I only have the fogging issue if I don’t have my mask seated properly. Not trying to dis the idea but if your using your mask correctly fogging isn’t a problem.

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