With all the DIY masks on the market right now, I can’t help but wonder how well DIY masks really work, especially compared with the traditional disposable medical masks we are all more familiar with – you know the ones that cannot be found now for love or money.
To be sure, something is better than nothing. Especially if your goal is to block your own droplets from potentially infecting others. We are all potential vectors of Covid-19, after all. Even if we are asymptomatic, we could be carriers like Typhoid Mary. This is the #1 reason I wear a mask. For YOU.
But I’d also like my mask to provide some benefit to me. I have to be honest – I don’t think the masks I am seeing many people make, wear, and sell, do much to protect the wearers. How can they when they simply do not filter? I’ve seen people wearing masks that I can only describe as decorative, they are doing so little to protect. A Costco checker at a store I visited a couple weeks ago, was wearing a colorful cotton crocheted mask that I could clearly see her lips through. That one wasn’t even protecting others from her potential coughs.
For the past few weeks I have been making, donating and selling reusable cloth masks and I have tried to make ones that are effective at both blocking my own germs from spreading AND filtering out potential germs in the air around me. I’ve been using the blue shop cloth that was mentioned in an article by Business Insider. But I did not test it myself.
Since we needed a homeschool activity this week, we decided to devise a test to see how well our masks, and masks made from other common materials, filter.
Mask Making Materials Tested:
- Two layers of quilting cotton
- One layer of Zep Brand “blue shop towel”
- One Disposable “Hospital Grade” Procedure Mask
Materials Used for Testing:
- Flour – Similar particle size to dust, much bigger than Covid-19
- Cornstarch – Very small particle size, more similar to Covid-19
- Vaccum Cleaner
- Black Socks (to show whether white powder makes it thru the mask materials)
For this experiment we started by ensuring our vacuum easily sucked up both flour and cornstarch, when unobstructed.
Next we tried sucking up both flour and cornstarch thru a black sock. The vacuum had little trouble “inhaling” both the flour and the cornstarch thru the sock. This was important for two reasons. This showed us:
- Socks (and similar knit materials) do little to nothing to block particles from getting through
- A black sock could be used to “show” whether white powder was getting through the other materials we were testing. We included a black sock as a bottom layer in all the subsequent tests.
For the next test we tried out two layers of quilting cotton. This is similar to many of the masks being sold and donated right now, or to a doubled bandana. Our first test was with flour. We attempted to suck up the flour thru the two layers of cotton. If the cotton material was working, we would not see any flour on the sock that covered the vacuum nozzle under the cotton.
We were surprised to see that in fact no flour got thru the cotton material. The cotton was doing an excellent job of blocking the flour.
Next we repeated this process using the cornstarch, which has a much finer particle size – more similar to Covid-19. Unfortunately, with the cornstarch, a significant amount of white powder got through the two layers of cotton.
We repeated the test with our blue “shop towel”. The shop towel blocked the flour entirely and was more effective at blocking the cornstarch. A very small amount made it thru.
We repeated the test two more times – with medical grade masks and with a sandwich of the two cotton pieces and shop towel. These two tests were the most “successful” – you had to use a large magnifying glass to detect the amount of cornstarch that made its way through either of these.
It’s important to note that cornstarch particle sizes vary – and can actually be even smaller than Covid particles.
Was this a thorough and comprehensive test? No. But it was a quick and easy way to really understand how different materials work better/worse as filters, and how not all masks work the same. But the ideal material is not letting the finer particles through… That much is clear!
Our conclusion was that not all materials make great face masks. In particular, socks, legging and t-shirt materials may be dangerous if used without an additional filter inside. They may be giving people a false sense of security.
It was gratifying to see the masks we have been making, performing so well. Although we had read the studies about blue shop towels, we really just took them at face value (pun intended). Seeing is believing!
You can repeat this experiment at home with your own masks and materials. Try out a coffee filter or a pillowcase. It’s an interesting and timely homeschool activity. Let us know what you discover!