Sewing Instructions for COVID-19 Masks

There are a variety of YouTube videos that instruct people how to sew their own masks:

Example 1: UnityPoint Health sews the Olson mask

Example 2: Maker's Habitat: Simple DIY Mask

Example 3: Atlantic Health: How to Make a Facemask

Example 4: Adafruit: Sew a Simple Facemask

You also search videos on how to use a sewing machine, like this primer.

Step 1: Source Materials

There's a range of possible fabrics and, although some are better than others, the general consensus is that any face covering is better than nothing. Here are some common household materials along with an approximate rating of how effective they are at filtering:

Be cognizant, however, that--generally speaking--as a material increases in filtering ability, it decreases in breathability, making it more difficult to breath normally for the user:

There's some limited evidence that the common blue shop cloth can filter 95% of .03 micron particulates, which--if true--makes it comparable to an N95 NIOSH-rated respirator.

Therefore, because other items are too bulky or reduce breathability excessively, my initial recommendation is to use a tight-cotton blend fabric doubled layered as the base fabric--preferably using high thread count or antimicrobial fabric. Additionally, you should sandwich a double-layered blue shop cloth between your mouth and the facemask as a second layer of protection (shop cloths are available at these retailers: Amazon, Home Depot, Walmart, Lowe's, Advanced Auto, AutoZone) If possible, you should wash the fabric mask after each use and discard the blue shop cloth between each use.

At Cornell, Cayuga Medical has provided volunteers Halyard Sterilization H200 Wrap (available for purchase here) and we are using two layers, along with a softer tissue layer made of a lighter grade of sterile wrap. Sterile wrap can be safely laser cut for rapid scaling of production. Made in the USA, it doesn't currently have any known supply chain shortages.

Step 2: Cut Fabric: Layers to 7" x 7" Squares and Straps

You might notice that the third layer--which goes in contact with the face and is softer--is slightly larger (approximately 7.5" square). We cut our sterile wrap using a laser cutter, making the edges harder and slightly irritating, so the softer layer protects the user. We used one layer of the same material to cut long straps (approximately 36") that will be tied together behind the user's head to secure the mask.

Step 3: Sew a Line Down One Side Near the Edge

Ultimately, you're going to have three parallel lines sewn across the square, as in the diagram below. The first line will be approximately between 1/8" & 1/3" from the top edge (Sew Line 1). The second line (Sew Line 2) will about 1/3" to 1/2" below that first line. The space between these first two lines will create a sleeve through which semi-rigid wire can threaded through. This wire will later mold tightly around the user's nose. The The final line will be approximately between 1/8" & 1/3" from the bottom edge (Sew Line 3).

Sewing Pattern Illustration

Pro-Tip: Chain-Sewing

To maximize productivity, don't just sew one at a time. Line up about 10-or-so squares, and sew straight down all the edges all at once. This is known as flagging or chain-sewing.

Chain-Sewing

Step 4: Sew the Second Line

Similar to the first line (Sew Line 1); sew this second line (Sew Line 2) about 1/3" to 1/2" below that first line. These parallel lines create the sleeve for the wire.

Step 4: Sew the Third Line

You might have to flip the pattern over to sew line three along the bottom edge (Sew Line 3) as in this photo:

The final product should be a chain of these fabric squares:

Step 4: Separate each square and insert metal wire into sleeve

If your squares are linked from the chain method, snip them apart.

You can use a wide variety of malleable metal inserts. This photo shows a small sample of the material we used.

Simply slide a four-inch-or-so section into the sleeve:

Step 5: The Fold

Place the top end of the fabric-square (the side with the sleeve and metal insert) on the edge of the table. Most of the bottom section of the square will be hanging off the side of the table, but have approximately the top 1 & 3/8" of the fabric firmly on the table as in this photo:

Using two hands--one on each side of the fabric--and four fingers on top of the fabric and table, press the fabric hanging off against the side of the table with your thumbs as if you're going to pinch it, creating a right angle in the fabric. With the side (thumb) section of fabric (approximately thumb-width; it doesn't have to be exact), slide your thumbs up towards the top of the table, creating a roll--or fold--in the fabric. Slide this fold under the 1 & 3/8" top section on top of the table and move the entire mask further onto the table in preparation of repeating this technique further down:

Repeat the step above twice more to create three folds altogether:

Sterile wrap has a certain amount of "memory" in that it creates and partially holds a folded line once pressed. This characteristic is very advantageous as most common fabrics, like cotton, might need to be iron-steam-pressed to hold the seam.

Step 6: Stitching the folds and attaching the straps

While using one hand to press your fabric against the table and hold all the folds in place, use your other hand to grab the strap in the middle. Align the middle of the strap long the edge of one side of the fabric directly across the folds:

Splaying your fingers wide across the piece and using significant finger pressure, press the folds together to maintain the design and keep the strap in position. Lift the entire piece--while maintaining the shape--and place it on the sewing bed in preparation to sew the strap on. Drop the sewing foot on to the piece, pinching the strap into place, and sew a line along the strap--affixing the strap onto the mask and stitching the folds into place:

This is what the strap should look like:

Pro-Tip: Backstitching

To prevent this seam from unraveling, backstitch at the beginning and end of the sew line:

Step 6b: Attaching the other strap

Remove the entire piece from the bed of the sewing machine and grab another strap. Place the middle of the new strap along the other edge, pressing the folds on that side into position. Rotate the piece and perform the same process as in the previous step on the other side to affix the other strap and stitch the folds together:

Step 7: Trim of excess threads and you're finished!