There’s no way I’m the only person who has had this idea. But I don’t see a lot of talk about it, so it seemed like it was worth exploring.
Breath masks are not 100% good for anything, we are told, and viruses are much smaller than most filters catch – but the mask might catch inbound or outbound droplets and that could make all the difference. 0.3 microns is the upper end of useful, and that’s the range HEPA (High Efficiency Particulate Air) filters are designed to catch. So, I believe that puts HEPA filters into the “might be useful” category.
That’s a central air recirculating system filter pack; there’s a huge stack of them for sale at the hardware store, $20 a pack. It’s a .3 micron filter (but the packaging is a bit dodgy about how well it is expected to perform at that size) It’s designed to catch pollen, cigarette smoke, very small bugs, and droplets that some virus sufferer coughed into the air near you. I’ve used these filters before, for a bunch of things (filtering silver nitrate before I switched to my vacuum filtration system with the bucholtz flask) – they’re just hot glued into the cardboard frame and you can de-frame them in seconds.
After that, you grab your glue gun and some string and you have a HEPA mask.
The air conditioning filters are really great to work with because they have a mesh of fine aluminum wire embedded in the layers, so you can shape it and it’ll keep its form. I realize it looks like crap but the air was only coming through the filter and not around the edges. So, that’s a win.
There’s another good source of HEPA filters and that’s vacuum bags and vacuum pre-filters. This is a pre-filter from my old Filter Queen(tm) vaccum that died and was gotten rid of years ago. Naturally, I still have the pre-filter because I’m a packrat.
I feel a bit bad about this; I really just threw it together. A bit of hot glue on the top, and glue the sides to the bottom, then add a string. I appear to have misplaced my nazgûl cloak, so I just wore the jacket I was wearing while turning some wood – everything was covered in dust. So I dusted my old glasses (those are not what I normally wear) and hat and set the camera up with remote and flash sync. I was lazy with the mask, too – it’s held on with nice big dabs of spirit gum. It’s literally glued to my face. Surprisingly, with all that surface area and the very light filter material, it was very comfortable except I kept banging my “beak” into things.
A friend of mine who is involved in a “maker space” says that a bunch of the crew have been making cloth filter masks for workers who need them. Now, they are going to have pockets where you can slip a piece of HEPA material from wherever you can find it.
I hope things don’t get so bad that I want to wear a mask to the grocery store or something like that. But, if I do, I’ve got a really nice full-face 3M chemical mask that I used to wear when I was mixing up collodion (ok, mostly when measuring out cadmium bromide) – it’s got activated charcoal chemical filters on it now but I could easily hot glue some folded HEPA material over the inlet area of the filter bodies. I also have a powered filter mask that I wear when I’m grinding lead off of wrought iron, but the fan motor makes a weird whine and it’s like having an air conditioner attached to your face – no fun in the winter.
Back in the day, I would have painted my entire backdrop sweep a nice charcoal gray to make the picture more somber, but it seemed like a waste of a half hour and a half gallon of paint just for a throwaway shot.
Spirit gum is funny stuff. I believe it’s just pine tar in ethanol. It’s got to go back deep into theatrical history. A lot of the time, these chemical formulations are hit upon and they endure far past what ought to be a sensible time. For example, why are they still using gutta percha for root canals, instead of some kind of nice, neutral, gooey silicone? When I was doing wet plate photography, I made my own varnish the way they did in the 1860s, by dissolving gum sandarac (sandalwood tree sap) in everclear – you can’t buy process ethanol in Pennsylvania because of the stupid quakers – which I had to buy down in Maryland when I visited my parents. Anyhow, it was nice to smell spirit gum again, it’s been a while.