This will be the basis for the vacuum cleaner bag pattern, but THIS mask can be made now, with cotton (for maximum laundering potential) to use as a stand-alone community mask, or as an N95 mask cover to help extend the life of masks for medical personnel.
The vacuum bag pattern will not be sewn.
Sewing through a vacuum bag destroys its structural integrity by introducing around 200 .5mm to .7 mm holes into fabric that’s supposed to filter down to .01 microns. A millimeter is 1000 microns, so a hole .5 mm wide permits 50,000 .01 micron particles to march through abreast. Don’t do it!
Do not waste bags learning this, because the supply chain for vacuum bags is smaller than the supply chain for medical masks and construction masks.
This also applies to any medically recommended fabric, like surgical drapes. Don’t put holes in them unnecessarily. If your hospital system is asking for sewists to make masks from drapes, follow their directions precisely.
And if you notice something is wrong, like they’re asking you to poke holes into mask fabric, speak up! Just because a doctor is an expert at medicine doesn’t make them an expert in materials science! They’re tired, they’re overworked, so be their extra eyes and safety check.
The vac bag mask will be up as soon as I’ve got durable adhesives. But do not sew them. Do not. There is no safe way to sew them, and this is not a case of the perfect being the enemy of the good. It’s destroying a potentially lifesaving material through not understanding it, and giving the medical workers using them a false confidence in a material that will not protect them.
These one piece masks will fit OVER an N95, which keeps the N95 cleaner and allows them to be used longer. The fit will be tight, but all masks should fit tight, because a loose mask leaks air.
Multiple layer cotton masks will filter around 70 percent of aerosolized particles and are sufficient for community protection. This is considerably more protection than being barefaced.
Drafting the Mask pattern
This is the image for the pattern. You can download it and print it at 100% scale.
With a caveat: your printer will probably cut the edges of the image off. For the most part this doesn’t matter — just use a ruler and continue every line to the edge of the paper, then cut out the triangle.
Or you can draft the pattern relatively quickly. This time, we’ll use use the 8.5″ x 11″ measurements. The A4 metric process is similar, but the measurements differ.
You will need:
- A sheet of copy paper
- A precise ruler
- Pencil and eraser (sharp mechanical is best)
- A protractor or a quilting ruler with the 45° angle marked is useful, but not essential.
Orient a piece of 8.5 x 11 inch sheet of paper in LANDSCAPE in front of you, so it is wider than it is tall.
Draw two lines, bisecting the paper: one from the middle of the long edge to the middle of the opposite long edge, and one from the middle of the short edge to the middle of the opposite short edge. The middle of the long edge is 5.5 inches from a corner; the middle of the short side is 4.25 inches from a corner.
At the top of the page, draw a line along the long edge ⅝” inch from the edge. This is your seam allowance.
Repeat at the bottom edge.
On the horizontal middle line, measure 2.5 inches outwards from the center (where the middle lines cross.) Make a tick mark, A. Repeat for the right side. Mark that one B.
Measure 1 inch up from the bottom left corner of the page, on the left edge. Make a tick. Label this one C. Repeat for the bottom right edge; label this one D.
Measure 1 inch down from the top left corner, on the left edge. Make a tick. Label this one E. Repeat for top right corner; label this one F.
Draw a straight line from tick A to tick C.
Draw a straight line from tick A to tick E.
Draw a straight line from tick B to tick D.
Draw a straight line from tick B to tick F.
Check your angles. The angle ACE should be 94° at A, and 43° at E and A. Also for triangle BDF.
Measure ½ inch inwards from the left upper corner of the paper. Draw a straight line down to the angled line. Repeat for each corner — this is fold over seam allowance for casings.
Cut out the triangles ACE and BDF.
This is the shape of the pattern.
Each mask requires at least TWO of these.
These are much easier 3 and 4 layer masks than pleated masks.
If you are in the A4 paper world, draw the center lines, but adjust the measurements:
Tick marks A and B are 7.5 cm from the center. C, D, E, and F are 3 cm from the edge. G, H, I and J are 5 cm from the center line.
All seam allowances are 1 cm. Your angle will be slightly off of 90° and your mask will be a little longer and narrower, but if you ensure your angles match on both sides of the center line, the mask will be fine.
Cut at least 2 pieces from your fabric.
Fold the casing hems towards the center; press.
Stitch down all four on each piece of fabric.
Lay at least 2 pieces together, right sides together, wrong sides out.
If you’re using 3 layers, it’s right side up, doesn’t matter, right side down. If you’re using 4 layers, it’s right side up, doesn’t matter, doesn’t matter, right side down.
Stitch both long sides with a straight stitch, using a ⅝”/ 1 cm seam allowance.
Place a pair of twist ties, a piece of pipe cleaner, 4 inches of coated copper wire, or 4 inches of brass or copper jewelry wire on the top seam allowance, matching the center of the mask to the center of the wire.
Zigzag over the wire. Repeat for the bottom edge. Turn right side out, press the seams. Now this mask can be worn in either orientation.
Stitch down the long sides again, using a ⅝”/1 cm seam allowance. This is the casing. (Sorry, this picture is out of order. This step can be done at any time after this point.)
Fold the bottom up to the top, on the center line, with the side you want out to the world on the inside. The two angled edges should meet. (You can wiggle these a little. Fabric is forgiving.)
Set your sewing machine to a 4 mm wide, 1.5 mm long zig zag (or a wide, fairly tight zigzag if your machine doesn’t speak metric) and sew both angled edges near the raw edge. Do not sew over the folded edge of the casings.
Turn right side out, thread twill tape, elastic or fabric ties through the casings, or proceed to the Jersey headband instructions. Trim any dangling threads.
The one piece mask is finished.