Monday, May 25, 2020

My Personal Mask Design

I've worn masks a lot during my career. I inspect refinery equipment and work in a chemical environment. Fit and comfort for all-day wear are a big deal for me. Thus, following standard principles, I made my own. I kinna figures this would last some months, which it has and will.

I've been asked to post details, so here we go. I know there are a million posts out there.

The real plus of this design is that there are no leaks. They call it a duckbill mask. It may look odd, but the fabric is away from you lips, speaking is easier, and there is more fabric for easier breathing with good filtration. The pattern came from a doctor.

It should be worn high on the bridge of the nose for best fit. This can be a problem with glasses, but I can get it to work (I had not properly adjusted this one yet).

Chin fit is also important. Watch for gaps under the jaw. Tighten the elastic as needed--it is adjustable for a reason.

  • Cut 3 pieces to the pattern (see below). You will actually fold it on the narrowest side, so it comes out looking like a fat hourglass. I cut the fleece with a hot knife--it's a sailor thing.
  • 1 layer fleece (comfortable, maintains shape, and very important, helps with sealing) and 1-2 layers fine sheeting (filtration). Lay them on top of each other.
  • Seam down narrow part of hour glass. This just keeps them in place.
  • Fold it on the seam and seam the edges together and trim with hot knife--it's a sailor thing. Of scissors and flame. It won't fray much. Leave at least 1/2" hanging out near the long edge; you will need this to attach the elastic.
  • Cut a piece of aluminum roof flashing ~ 1/2" x 4" and center this inside one of the long hems. This will make the bridge of the nose stiffener.
  •  Hem the long sides. These will bear on the face, so fold the edges under. This also provides support and creates a thick, wide sealing surface.
  • Melt holes for the elastic in the outside hem allowance using a hot nail. This is why the seams are flat and wide.
  • Thread the elastic. 1/8" cord or 1/4" flat. Tent pole shock cord is perfect. One goes under the ears, the other over the head. By using one continuous shock cord it is more adjustable and easier to don.
  • Carefully bend the nose piece to fit. In fact, nothing is as important as making sure there is no edge leakage. A leak is N-zero. By keeping the stiffener thin and flat it works with glasses, a common complaint.

Although it should washed now and then, they will self-sterilize if not worn for 10 days. Leaving them in the sun is also helpful. So make several and don't go out every day. Then you don't need to wash them too often.

Here is a good video that shows a similar mask made from a HEPA vac filter. I did this, but it's not very comfortable and is not washable. But it is an excellent design.

Here is the pattern. However, I add 1/2 inch on the sides for hem allowance and 1 inch on the long sides for hem and to tuck in the nose stiffener.

I did not sew on the elastic to the mask. One long loop threaded through the holes (melt with hot nail) is easier and more adjustable. The cord is tied with a double fisherman's knot so that I can easily slide it to take up slack, should the elastic stretch or for different size heads.

It's probably not far off N-95 or may be there. Yes, the masks are primarily to keep your own spit, but why not do it right?

I've made a dozzen of them, for my wife and I, and for my 90+ parents. 

Yeah, it's doofy looking.  Too many people choose masks for appearance or because they "look" medical. This works and stays in place through any activity. Good for mowing the grass and shop work too.


Of course, this is why you wear a mask: 

No comments:

Post a Comment