Build Your Own Face Mask and Shield From a Soda Bottle

Gray-haired man with a clear plastic face shield

Mark Sanders

Industrial designer Mark Sanders shows us all how.

UPDATE: Some readers are complaining about our calling this device a respirator, which is defined as "a masklike device, usually of gauze, worn over the mouth, or nose and mouth, to prevent the inhalation of noxious substances or the like." I have removed the word from the title as it was causing confusion. The designer, Mark Sanders, is an experienced industrial designer who has worked on medical products. However, as we noted at the end of the post previously, this is not a tested device and is equivalent to a cloth face mask that you can also make at home.

Everyone is coming around to the idea that maybe masks or face coverings are a good idea. According to the Washington Post, new guidance from the Centers for Disease Control will recommend them. "In light of these new data, along with evidence of widespread transmission in communities across the country, CDC recommends the community use of cloth masks as an additional public health measure people can take to prevent the spread of virus to those around them."

Meanwhile, in the UK, industrial designer Mark Sanders of MAS-Design (known to TreeHugger for the Strida folding bike) is in isolation with time on his hands, and a big supply of PET bottles from his favorite ginger beer. He put on his Apollo 13 cap (let's make a CO2 filter out of all this stuff in the spaceship!) and designed a combo face mask and filtering device that anyone can make. I asked for some background and he gave me an essay, so in his own lightly edited words:

I've been seeing a lack of 6 foot distancing on paths, and in shops, etc. Also seen the use of both masks and visors worn by medics splashed all over TV. PET is a wonderful material, optically clear, very strong, far too good and useful to be wasted for just recycling. So limiting myself to household tools. for example scissors and items like Scotch tape, rubber bands. I dived into our un-emptied recycling bin and found about 8 PET bottles, then set about 'playing' with them.
Mask cutout in amber-colored plastic
Mark Sanders
I knew that laid flat/developed, the diameter of the (2 Liter) PET bottle would be enough to make a visor, but would the neck end also fit and seal around the chin/mouth? It took about 4-5 attempts with scissors, to get the universal ‘chin’ shape, and was surprised that it turned out to be a small ‘heart’ shaped 70mm x 50mm cut out at the end of the vertical cut in the cut-in-half the bottle. I knew it fitted as with the top on when sucking in, it sealed and it fitted both me and my wife (I’m long-faced, she is wide and small-faced). All the time to work out the best ‘heart shapes’ to seal, I was taking pictures to be able to see what I was doing. We found it almost stayed on its own, but elastic around the back of the head through 2 punched holes secures well. With a nice visor and down-facing ‘air-hole.’
The next challenge was stopping the virus to leave or enter ... at first, I imagined things in and around the neck / screw top of the bottle eg a simple bubble valve – filled with say soapy water – to allow air through but not virus, but this wasn’t so practical.
Bar chart comparing effectiveness of mask fabrics
Smart AIr CC BY 2.0
Next tried cotton in various forms, wool, scrunched up, etc stuck into the neck but this restricted air flow – A filter needs AREA to be effective. So I googled ‘ DIY masks’, most were sewn up and are labour intensive, but stumbled on an article and research which explored how filtration of various fine weaves of cotton (pillowcases), T-shirts compared to surgical masks. It showed that 2 layers of cotton (with enough area to get flow) gave almost the same filtration as a surgical mask. I Imagined tea towels dangling down from the bottle's neck, held by elastic bands – which apart from looking very odd and unappealing, puffed up like lungs when breathing. This is a possible solution, but the designer in me wanted something a bit more elegant than a ‘tea towel bib.’
Two masks with hoses
Mark Sanders
This lead to finding some old hosepipe, and PCV tubing and using the stuff we ALL have on our person, our clothes, as a large surface area filter !! I like this filter solution, although there are other solutions (e.g. as above and whatever others can think of... this is 100% ‘Open Source’ ) ... that does not need a piece of pipe. A friend, Norbert, in Australia, followed the instructions and used an old bike inner tube; he said it was OK but I worried about collapse on suction. The hose can be put down a shirt at the front or, if the hose is cut longer, around from the back.
The bigger the diameter, the better - for ease of breathing 13mm / 1⁄2” internal diameter is minimum. The more flexible the hose is, more comfortable it is to wear. The end of the hose is best cut wavy, along with more hose stiffness is best to avoid ‘sucking skin’ / sealing. (End of the hose can be stiffened with more sellotape.) There is enough leakage at the side and back to prevent steaming up, it is fully adjustable – with a rubber band and if necessary scissors to trim the sides, the breathing tube is best kept away from armpits which, obviously can be steamy and fruity.
Mask without hose
Mark Sanders

UPDATE: Mark shows a version with the hose made from rolled-up leftovers from the PET bottle, so all you need for this version is Scotch Tape to hold it all together.

I wanted a mask/visor that could be made in about a minute – eg for the basic version, without the hose. Other ideas to be explored by anyone – in the spirit of open source’ are making ‘hose’ or extended neck, from a rolled-up section of the unused half of the PET bottle, anything to get air from under clothes. Bearing in mind this is meant to be a quick, simple, super-easy to make, DIY, open-source “Hack” for Zero cost, using up ‘waste’ with the potential of being made, DIY by anyone, in millions ...... rather than a ‘Medically certificated’ mask and visor, It seems to work really well.

The full instructions are posted on ISSUU here.

Woman demonstrating clear plastic face mask with hose
Mark Sanders

There is a lot to like about this design. You can actually see the user's face, which is a plus in countries where people are not used to seeing others in masks. It acts as a full face mask so that it becomes almost impossible to touch any part of your face. Being plastic, it is easy to clean and disinfect. And it upcycles those PET bottles into something useful and valuable.

Just be careful with the scissors! And TreeHugger has not tested this and, as Mark notes, it is not "Medically certificated".