Question about mylar

[BlueHairedLass]

I'm looking to start producing these for my local healthcare team in St. Marys, ON. I was wondering if acetate transparency sheets might work instead of mylar? Sorry if this isn't the right place to ask this question, I'm new to Github and didn't know how else to make contact.

[tareko]

Great place to ask the question.

Short answer is: We haven't tested it and can't vouch for it. Is it not possible to find mylar at a local art store or something?

tarek : )

[BlueHairedLass]

Thanks for the quick response! I'll look into sources for mylar.

[kliment]

One thing I'll add to that - cellulose acetate (transparency sheets) are hydrophilic and retain water and water droplets for a long time, whereas PET (mylar) does not. Based on this I would recommend against acetate unless you have no choice. If you do use acetate, note it may not survive disinfection as many solvents attack it.

[kliment]

I just checked and heat resistant (meant for laser printers) transparencies are in fact made of Mylar! Only the normal (cheaper, not laser printer safe) ones are acetate.

[BlueHairedLass]

That is great information. I'm a little out of my league here, but I'm trying to do this research myself because goodness knows our doctors and nurses are busy enough!

[tareko]

Thank you for the insights, Kliment!!!

[ValerieORoat]

Hi Tarek
I'm collaborating with a Covid-19 Test Lab and hospital in Madrid, and I came across your face shield. This is my first time in GitHub. How long would you say it is advisable to use the masks made using your design and Mylar (including disinfection) before disposing of them?
I also found this Mylar equivalent https://www.m-petfilm.de/en/hostaphan-polyester-films/

[amashari]

Hi Valerie,
We have not done long term testing. As far as we know right now, if you follow the decontamination procedure, you can keep reusing them as long as there is no obvious structural problems. The mylar will get scratched and cloudy over time, at which point it will need to be replaced (just the mylar screen). We don't have data right now in how many cleaning cycles a typical mask will tolerate.