- Certified fiberglass-free HEPA filter (or fiberglass-free MERV-16 if HEPA is not available)
- Spunbond polypropylene or clean non-woven reusable grocery bags made from spunbond polypropylene (not coated reusable grocery bags)
- Thin spunbond from hair nets or shoe covers
- Citric acid (or lemon juice)
- Low temp hot glue and gun (high temp hot glue tends to melt HEPA filters and spunbond too much)
- File folder fasteners for the nose piece (not needed if only make cloth mask insert)
- ⅜” elastic, two pieces 11” long (not needed if only make cloth mask insert)
If you would like to see more detail, click on the images below to see larger versions.
Spray citric acid-water solution (¾ tablespoon of citric acid to 1L water) onto fabric. As long as you do not feel irritation while wearing it, you can spray as much as you can to improve performance against viruses. After spraying, dry it in a ventilated room.
If needed, remove the HEPA filter and flatten it. Gently fold the HEPA filter in half and use the template to cut the folded filter into the mask shape (solid outline on template). HEPA filters often contain fiberglass and appropriate precautions are needed such as wearing a mask and protective clothing. Seal any holes in the HEPA filter.
Fold Spunbond in half, placing the template edge along the fold, and cut out the outside layer of the mask (solid outline on the template). This is the outside layer of the mask.
Repeat step 3 using thin spunbond polypropylene that was sprayed with citric acid.
Now, for the inside layer of the mask, fold spunbond in half placing the template edge along the fold. Cut out using the template including the extra ⅜” line at the top of the image below (this included area is also labeled in the template).
Assemble the 4 layers aligning the edges. The inside spunbond layer has ⅜” strip that will be folded over later to ensure only spunbond makes contact with the face.
Glue the outside edges ensuring a tight seal is made leaving the top edge where the nose piece is added open. Press the edges together to ensure the layers are glued well.
Take two file folder fasteners and bend the ends over so they are 6” long to form the nose piece. Use a round handle of a tool to pre-bend the nose piece.
Place the nose piece under the outside layer and glue in place.
Fold the ⅜” strip from the inside layer over the top and glue in place.
Staple the elastic across the top edge at the corners using two staples in a cross on the inside of the mask. Repeat on the opposite edge.
Glue and press the sides of the mask together.
While wearing the mask, bend the nose piece to form a tight seal. It is important to make sure the mask seals and that the nose clip holds the mask in place.
Mask User Seal Check
Alternative nosepiece material options listed with preferred at top:
- File folder fasteners
- Pipe cleaner
- Nite Ize Gear Ties or Foam Twist Ties
- Aluminum foil folded up
- Wire- 12 gauge copper craft, 16 gage steel,
- Paper clip
Elastic/material used to secure mask to face options:
- ⅜ inch elastic cord
- ¼ inch elastic cord
- Elastic from socks