Introduction: PPE Face Shield
Our local hospitals are very short of Personal Protection Equipment (PPE), particularly face shields (visors). Here is a design which can be made in minutes and in batches of 100.
As you can see in the photos, it has a vent at the top where the foam stands away from the skin. (I really do need a haircut don't I?) The vent helps prevent fogging.
If you don't wear a mask over your nose and mouth then the shield is OK. But when you wear a mask the shield fogs even when you sit still. Fogging is much worse if your mask doesn't have the little bit of metal that clips over your nose.
So I added foam stand-offs to make a vent for your breath to escape. It helps a lot. There's no fogging if you're working normally but still fogs a little with more exercise. I'm told by a nurse that commercial shields fog up only if the mask is not sealed properly over the nose. Otherwise they're fine. Some shields do have vent holes at the side because of the design of the mask.
Maybe a vent is bad because it allows greater ingress of body fluids. It's your decision. The nurse reports that the shield is only there for splashes into the faces rather than full protection from aerosols. (That comes from the P3 mask.)
Step 1: The Build
The sheet is A4 acetate transparency film. Punch 4 holes with a paper punch. I put them at 5cm and 12cm from the center line (That's how my 4-hole punch is measured.)
A4 transparency film should be available from any office stationery store or search eBay for "A4 transparent film". For instance:
The yellow padding at the top is 5mm camping-mat foam. It's the sort of thin camping-mat foam you really don't enjoy sleeping on. You local camping store might help. (All our non-essential stores are now shut.) Or search eBay for "camping mat". For instance:
Cut a 30x300mm strip of foam. Glue the stip onto the transparent sheet with good quality double-sided tape so it covers the holes you punched.
Punch holes through the foam to go through the holes made by the hole-punch. I used a leather-punch. Burning holes with a soldering iron is also good. The heat seals the edges - but it really messes up your soldering iron bit.
I used a total of 119cm of elastic. 5mm wide flat elastic sewing cord is ideal. I happened to have a reel of 8mm elastic. It's red with a frilly edge - quite stylish.
Thread the elastic through the holes. I guess you could use a large darning needle rather than a leather-punch.
The straps over the top of your head help hold the visor up. They should cross on the top of your head. The ends of the elastic are sewn or glued onto the back-strap.
Add a cord stopper toggle at the back of the head so you can adjust the tension in the elastic for different people:
If you want to add vents - which I recommend - cut eight 30x30mm squares of foam. Glue them together to make four pairs - each 10mm thick. Then glue the four squares onto the foam strip equally spaced. That will make a 10mm gap through which air can escape and helps prevent fogging.
Your face shield is now finished. It's a lot tougher than I expected it to be. A4 transperency film feels flimsy but I've crashed into it a few times when I forget I'm wearing it and try to drink a cup of coffee. Yes, it's so light and easy to wear you forget it's on.
If you're making them for other people to wear, take precautions not to cover them in germs. Work with a mask and Nitrile gloves. Clean your work surface with disinfectant. Take the materials out of their packaging only when you need to. Store the finished masks in a sterile bag such as an unopened bin-bag. But these masks are not expected to be 100% sterile - the nurse who puts it on will already be covered in who-knows-what.
If you're supplying them for others to use, print the line drawings above that show how to fit them.