how to deal with old filament
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@mrehorstdmd I am not printing printer parts in PLA -- sorry if I was being unclear. I am reasonably fine with PETG parts, but I'm gravitating towards ASA more and more.
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I also have problems with the PLA becoming brittle inside a PTFE tube. It's different between different brands. EasyPrint from 3D Prima is worst I have, It's enough for it to be left half a day inside PTFE and it's broken in several places.
Generally all materials get brittle when they absorb moisture and I dry even my PLA for better end results. -
problems again, opened 7+ year old box of ABS ... behaves like crap .. does not crumble like PLA but it's rather unprintable ... 24h in dehumidifier at 70C, did not help, still unprintable.... I don't get it, was never exposed to UV, in original vacuum bag with desicant, no water... also does not print like wet filament it just behaves weird - poor layer adhesion, mega warping, curling out of the nozzle...
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At the start of the covid-19 pandemic I used several old rolls of eSun ABS that were never stored properly to print faceshields. I did dry them before using as insurance policy, and had no single issue with them. Printed like new.
The advantage of ABS was that I was able to heat all the faceshields I printed to 80C, making sure that no virus was alive on the shipped parts.
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@DaBit this was also eSUN and also ABS ... only around 8 years old I think and it was in the pile with PC and PA so that's why it was unnoticed for a while
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This looks similar to a problem experienced in the UV ink print industry when printing older new media vs fresh new media ( both never used and in sealed bags) plastizers in the older media migrate to the print surface causing unexpected print results .
Turns out PLA uses all kinds of plastizers as well and they also can change wildly over time depending on what plastizer is actually used , which may explain what your experiencing
I went down a rabbit hole of info , this one was an interesting read
Printability, Mechanical and Thermal Properties of Poly(3-Hydroxybutyrate)-Poly(Lactic Acid)-Plasticizer Blends for Three-Dimensional (3D) Printing
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@DigiD said in how to deal with old filament:
Printability, Mechanical and Thermal Properties of Poly(3-Hydroxybutyrate)-Poly(Lactic Acid)-Plasticizer Blends for Three-Dimensional (3D) Printing
The article you point to seems to indicate the plasticizers were needed in the PHB/PLA mixes, which are extra-biodegradable mixes. In those mixes, they behaved badly without plasticizers. I didn't see anything in there saying pure PLA has plasticizers. As far as I know it doesn't. Anyone an expert on this?
On the other had, I have had a few spools of PLA go completely brittle. It's been more a problem with 3mm diameter filament, which is already very stiff, and I think a bit of differential embrittlement of the outer shell makes it useless.
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@mendenmh I would bet the PLA+ blends have more plasticizer.
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I have some 11 year old natural PLA from bitsfrombytes, 3mm dia, that you can't unspool
.. it does not crack as easy as some modern old PLA but is hardened so much you can't uncoil and straighten it .. I did manage to print with it using a heat gun to heat it up while unspooling but is a manual process acceptable for test only, not for actual printing; it's only total of maybe 500g so not really a big deal (when I remember how much I paid for it it hurts) ... but this last issue was with ABS. Not sure why this happens. I seen few times in videos of ppl like Tomas or Joel that they mention "these are old spools of filament that is unprintable" so they too have the issue of - after some time on the shell filament is unusable, but why ?!Also, what's weird, as I already mentioned, I have pieces printed out of PLA that are 10 years old and still are totally ok, never became brittle?! Why does filament becomes extra brittle and week while printed part does not ?!
