DIY masks can block coronavirus. Here are tips before you sew

At first they said not to bother with masks; they didn’t work, they said.

The messaging has changed now, with studies showing that even masks sewn by hand block half the coronavirus-sized particles blasted your way.

President Trump said on Friday evening that we should wear masks in public now, as the coronavirus begins its surge. (He will not wear a mask, however. "It's only a recommendation," he said.)

If you have access to surgical masks (not the coveted N95 masks; this is the lesser version), those should be your top choice.

The DIY mask is the last resort, but those who have studied these masks agree that they are far better than nothing. The scientists also find that you must still wash your hands vigorously for these to be effective – this is not the time to go lax on handwashing.

Given this, we researched the best materials for masks and have embedded mask-making tutorials below.

Materials best at preventing coronavirus from penetrating:

1. Surgical mask
2. Vacuum bag
3. Dish towel
4. Car shop towel

Surgical masks are three times more effective at blocking a bug than homemade masks, according to an article in the journal Disaster Medicine and Public Health Preparedness.

But we assume you are here because you can’t get a surgical mask. Next best are vacuum bags and dish towels, but those are hard to breathe through.

Scientists therefore recommend a 100-percent cotton shirt or pillowcase. The cotton shirt prevents roughly half of coronavirus-size particles from penetrating.

Dr. Peter Tsai of the University of Tennessee recommends car shop towels, which are a strong, tightly woven fabric.

Don’t use paper towels and wet wipes. Viruses sail right through those.

Silk and scarves are the least effective materials … but again, better than nothing. (And when they say better than nothing, they mean MUCH MORE EFFECTIVE than nothing.)

And this excellent tutorial from The New York Times. (Note: Since this story published, a seasoned sewer told us that she failed twice at making a mask from this pattern. We are leaving it here with a warning that this has its critics.)

Before you start, some tips:

A mask should be snug, covering the bridge of the nose to below the chin.

“Some particles in aerosol form may enter from gaps between the mask edge and the face without going through the mask body,” writes Dr. Tsai, who invented the technology that makes the filter media of the N95 face masks. Tsai works at the University of Tennessee.

But! Don’t sweat fit too much. Any barrier helps.

Pre-wash the shirt, and wash it after every use. A study out of Vietnam showed that medical providers who did not wash their cotton masks fared worse than those who wore no mask because of the bacterial buildup in the masks.

From an open source Facebook group dedicated to making protective equipment: “Use a mild detergent without a lot of fillers, HOT water and NO dryer sheets or fabric softener. The pre-wash removes the finishes and other chemicals the manufacturer puts in the fabrics before selling. Use the long cycle on your machine and then throw fabric into dryer to shrink it up.”

And finally:

Some medical providers are using paper clips to connect the elastics behind their head, because the elastic over their ears is painful.

Wash your hands before taking off your mask, and then wash your hands after taking it off. That's the moral of this story: Keep washing your hands.