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PLA Get's Brittle  

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Bob
 Bob
(@bob-2)
Reputable Member
PLA Get's Brittle

I'm curious whether others have seen what I've seen.

I've noticed that when PLA ages it gets brittle.  I've had some spools of PLA that I've had for years and printed with to the end.  The very first spool I got with my Prusa I3 Mk2 printed my first prints with that printer, but also was used to print my first prints on my Ender 3 and my Prusa Mini.  If you know the release dates of the Mk2 and the Mini you'll know that covered about 4 years.  When I'm done with a roll I store it in a large ziplock bag with dessicant to reduce the filament getting wet.  This has been mostly successful for me with PLA at least, PETG seems a bit more of a challenge as it gets more stringy with age which I believe is due to moisture.

Anyway, what I've noticed is that while my PLA may not show classic signs of excess moisture as it ages, it does get brittle.  I try not to print brittle PLA with my Mini as I've had problems with it feeding, my I3 (now a Mk2.5s) eats it just fine and the prints look pretty good.

I'm curious if others have experienced brittleness in their PLA.  I'm also curious if they find the entire roll goes brittle or just sections.  I can't say for certain, but it seems like only the outer ring of filament gets brittle and the stuff behind it is more flexible, but I haven't had enough samples to really verify that.

I'd like to hear what others think.  Is this a sign of moisture or something else.  What do you do when you find your filament brittle?

Cheers

-Bob

Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit

Posted : 20/01/2022 7:07 pm
Tracy
(@tracy)
Trusted Member
RE: PLA Get's Brittle

For me this is always a sign of too much moisture in the filament. Whenever it breaks by simply unrolling it, I stick in a food dehydrator for 3-4 hours and that fixes it.

Posted : 20/01/2022 7:36 pm
Bob
 Bob
(@bob-2)
Reputable Member
Topic starter answered:
RE: PLA Get's Brittle

Interesting, the odd thing is I don't see the other artifacts of moisture like stringing or bubbles, or other surface artifacts on my prints.

Cheers

-Bob

Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit

Posted : 20/01/2022 7:49 pm
jsw
 jsw
(@jsw)
Noble Member
RE: PLA Get's Brittle

I've only seen one case of wet/old PLA not being printable after a good session in the Ninja Cooker set on dehydrate.

This was a partial spool of FilamentPM silver-gray, (respooled from a 2kg spool by me) apparently the same stuff as the Prusa (non -ment) PLA that's included as a sample with new printers.

I found it in the corner of the spare bedroom, having been exposed to room air for well over a year.  It was so brittle that it snapped when unrolling.

I gave it two dehydrate cycles, but on closer inspection it had hairline cracks in it, which caused it to break when used.

I still have another partial 1kg spool from the same 2kg master spool, which is stored in the dry box, and is still perfectly fine.

Look closely at the photo below and you will see the hairline cracks that I am talking about.  I just trashed that one.

Posted : 21/01/2022 12:40 am
Crawlerin
(@crawlerin)
Prominent Member
RE: PLA Get's Brittle

Rumors have it it has something to do with light (either natural or UV). I do not remember anyone doing any tests on that.

Posted : 22/01/2022 7:57 am
Diem
 Diem
(@diem)
Noble Member

It's wet.

Cheerio,

Posted : 22/01/2022 8:01 am
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