Disposable blue masks have become iconic on faces and unfortunately, littered about the streets. The ubiquity of disposable masks is helping fight the pandemic, but all these single-use plastics have an environmental toll as well. This is a simple project demonstrating how to turn waste PPE into other covid-fighting safety materials. Also I just liked the kind of meta-idea of turning old masks into new mask accessories!Here's a video overview of the whole thing https://youtu.be/Yh32g7X9QNMI have been wanting to remix some of the many amazing projects people have come up with to fight Covid-19, and wanted to find a way to make use of existing materials that would otherwise be discarded. After some experimentation, I found out that some garbage PPE already can serve as raw material for new PPE!
Since this project started, there have been many others turning Polypropylene masks into things via injection or extruder molds (e.g. this bench). And they generally just toss the whole mask in. I think this is fine in bulk quantities, but if you are making thin sheets like us, that mysterious middle layer seems to make them much more fragile. so watch out!
Since we started this project, we have come across many better ways to consistently heat up the plastic. Now instead of just a hot plate, we moved to a panini press, and then a t-shirt press. Each of these you can get for 100-200$ and the ability to squeeze your plastic more consistently does wonders!
I have been wanting to remix some of the many amazing projects people have come up with to fight Covid-19, and wanted to find a way to make use of existing materials that would otherwise be discarded. After some experimentation, I found out that some garbage PPE already can serve as raw material for new PPE! There are many ear-saver designs but most of 3D printed or laser cut from brand new material. For this project I remixed one of the designs from the NIH https://3dprint.nih.gov/discover/3dpx-013777 and just made it a little more durable with the face design for using Polypropylene.
For those who just want to get to the meat of this How-to, here's the basic recipe:
Slice up a mask and keep the two outside layers (throw away the middle)
Heat the layers between parchment paper at 200C/400f
Fold and Reheat the Plastic to desired thickness
Laser cut your design into the plastic sheet
Materials and Tools
The supplies you need are pretty simple, and my hope is anyone can do this at home!
Old, discarded masks
Let sit for 2 weeks, or dunk in alcohol because they might be gross
Laser Cutting Files (Samples attached)
I used an electric skillet
You could also use an oven or toaster oven
Concept: Thermoplastics + 3 Layer Masks
Most of the standard, blue masks you see have three layers. The pictures above show examples of melting down each of the three layers and how they come out.
The two external layers are made from what they call "Melt Blown Polypropylene." This means in a factory somewhere, they have a bunch of polypropylene they heat up, and squeeze through a whole bunch of tiny holes while blowing air at them. This creates this nice random, static-y, fluffy material with VERY SMALL HOLES that is good at stopping particles and liquids.
The mask factory takes sheets of this fluffy polypropylene and slice them up to make the two exterior layers of your normal blue mask. These layers are hydrophobic and the main goal seems to be to keep your fluids in with you, and keep others fluids out. A cool thing about polyproylene is that it is a THERMOPLASTIC. This means you can melt it, put it in a shape, re-melt, and re-shape, (almost) as much as you want! This is how things like 3D printing work! It's also how plastic recycling in general works (Like all the great projects with the fine folks at https://preciousplastic.com/ ): you chop up certain types of plastic, melt it down, and re-use to make other projects.
Inside Layer (Problem Material!)
The center sheet is some kind of other material. It's hydrophillic and made to absorb moisture. The concept seems to be that any wet stuff that makes it through the outer layers gets absorbed in this layer. This is also why this layer tends to get mold and gross if you keep re-using the mask. This center layer is also the one that gives us some problems. We can't just melt down all three layers of the mask together, or we end up with a weak, brittle plastic.