Is there any risk involved, if hospital staff choose to re-use these ear-defenders by cleaning them?
Will alcohol react with either material?
1) After some months cleaning PLA earsavers, they cope nicely with Chlorine, alcohol (ethilic or isopropilic)and a mix of IPa and peroxide, but don't left then inside your car, they lose they shape, so don't heat sterilizing.
2) I use a pla printed UVc box and seems to be coping nicely too.
Refer to this video by CNC kitchen: https://youtu.be/txrXX0CQHhU
If you skip to 12:20 you'll see the graph showing how the strength of different materials is affected when the parts are submerged in IPA (isopropyl alcohol) for a number of hours.
PLA is virtually unaffected whilst ABS seems to lose some strength.
I know it was not mentioned by the OP, but I think that PETG was what some groups were requesting for the prusa sheilds (some were also OK with PLA, but preferred PETG). Interesting results in that video though, seems that PLA would be a better choice based on the testing. I could not find the video he mentioned on how they did with UV though. I know that PLA on the spool should not be exposed to UV if it can be avoided, but not sure about the final printed parts.
I haven't done any scientifically rigorous experiments with UV but in my experience having printed lots of transparent PLA parts for the garden that spend all day outside in the sun, they get destroyed after a couple of weeks. I suspect opaque PLA or PETG might resist UV better but I haven't tried that yet.
Thanks, I have not used PLA outdoors yet (only ABS and PETG), and probably will not knowing this info.
Thanks all for replying, and for all the info.
According to the healthcare professional I'm donating these ear defenders too, their cleaning product is Chlorine based. I guess worst case they get a little snappy/floppy after a while.
DesignSpark / RS were asking for both PLA and PEG in their National 3D Printing Society initiative.https://www.rs-online.com/designspark/do-you-have-a-3d-printer-you-can-help-to-fight-covid-19
"Material - The plastic visors must be printed in either PLA or PETG.
No other plastic is currently known to be suitable.
They can be printed in any colour.
All parts will be sterilised before they are given to NHS front line staff. However please follow the recommended guidelines where possible to minimise the risk to all involved."
Thanks again all,
That makes sense. Its just one datapoint but I've cleaned about 100 of those ear guards in PLA and PETG soaked in a bleach solution according to the CDC info here (https://www.cdc.gov/coronavirus/2019-ncov/community/organizations/cleaning-disinfection.html), followed by a water bath, rinse and then drying, and did not notice any negative effects on the plastics, they seemed to be unchanged.