Brittle filament

I purchased new filament: https://www.amazon.com/gp/product/B01EKEMUEK

I used it once, and observed that it created a hard glossy finish, unlike the filament I had been using before. I actually kind of liked the result. However, I observed right after a print, the filament was "cracked" about 5 inches above the extruder. When I tried to straighten it out, it broke right off. So then I started breaking off little pieces, by bending them back and forth 2 or 3 times, and realized the filament seems "brittle".

Is this normal for some filaments? In retrospect, I just re-read the advertisement on the Amazon page, and it says it is "Vacuum sealed in desiccant." I now remember when opening the package that while it was sealed, the package was not tight around the contents, like when something is vacuum sealed.

If this is "bad" or deteriorated, I still have a couple of days to return it.

I've found that my filament behaves in a similar manner, as if there is a contaminant entering from the filament end. It seems to be necessary to do as you have done, snap off pieces until the snapping ceases. I've found that if I leave a spool on the machine for any extended period, it will snap on its own, just sitting there. It's not really amusing to hear, but I've come to recognize the sound. Just today at lunch, I heard my current spool, out for only one day make that characteristic click/snap and it's broken a few inches clear of the extruder. Your reference to lack of vacuum is a key. It's not out of the question that the filament was on the shelf for some time and the vacuum is no longer. If you can snap pieces to get to non-snap filament, you'll probably be okay.

Personally I'd want to return it for a replacement or refund, from your description it sounds like the package had already been openrd if the vacuum seal had gone.

But like Fred said, perhaps you could see how far into the reel you get until you get to some good stuff.

So this makes me wonder, if time (which doesn't seem relatively long) deteriorates it, is that what will happen to the products I make with it?

The items you construct aren't going to be 1.75 mm or 2.85 mm thick and will have strength from the design, the layer adhesion and other factors. Things will break and if left in sunlight or exposed to heat, can fail. I have a PETG carabiner printed perhaps a year ago and the designed-in spring isn't quite as springy any more, but it still keeps the scissors hanging safely.

I suppose painting will help mitigate deterioration ?

When PLA is exposed to moisture for too long it gets brittle.. The roll is bad, if you can contact the manufacture they will probably replace it. All filament absorbs moisture and the results are different depending on what material it is, PLA get brittle, petg, abs and nylon get full of craters where the moisture boils out when melted

https://3dsolved.com/why-does-pla-fi...%20recommended.
https://www.bcn3d.com/the-causes-of-...-pla-filament/

When I first got my printer I bought this filament: https://www.amazon.com/gp/product/B093PTTFPJ It seemed to work fine, however I observed that there wasn't a strong bond between layers, and it didn't take a lot of force to break off sections of a part if they were small enough. I just assumed that's just how it is with 3D printing with PLA, like maybe it is more designed for models than parts that are going to be used in an assembly.

When that roll was running out, I bought this one (the brittle one referenced in the OP) and the first thing I noticed was that the parts were much stronger, and didn't break easily. I was quite pleased with that.

I am hoping that the strength characteristic isn't a factor of what also caused the brittleness, and that I don't lose the strength characteristic if I get a new roll that isn't brittle.

Don't know if you are in the UK but I tend to buy my filament from
https://3dfilaprint.com/product-cate...pla-filaments/

If there is ever a problem there is a phone number to call and emails get answered.

For the USA, I can recommend Matterhackers for good stuff. Their build series PLA is the lowest price and the quality is quite high. I've not had to call, but probably can, as they list a number in all correspondence. The email response is very good too. True customer service and good products and good prices.

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Originally Posted by fred_dot_u

For the USA, I can recommend Matterhackers for good stuff. Their build series PLA is the lowest price and the quality is quite high. I've not had to call, but probably can, as they list a number in all correspondence. The email response is very good too. True customer service and good products and good prices.

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Thanks, I'm giving them a try.

it really varies from roll to roll and manufacturer and colour to manufacturer and colour.

I have some pla filaments that if left on the machine overnight, will have broken between extruder and roll by morning, and some that can be left almost indefinitely without any breakage.

One of the problems is that there is no legislation on what additives go into 'pla' filament.
We have absolutely no idea what anyone puts into their mix and no legal way of finding out.

And also the colourant has a significant effect on all aspects of the the filament.

Then there's each persons 'workshop' enviroment. Temps and humidity vary, so a filament that for one user has no issues might cause problems for someone else.

I find with pla, that if it gets brittle, it tends to only be the first 8 - 10 inches or so.

Also, brittle pla snaps at the first bend.
Normal pla will take several bends to snap.

So it sounds like there is nothing wrong with the original posters filament.
It was just that first outer layer that was brittle, all the 2-3 bend stuff - was perfect :-)

You have to bear in mind that pla - while beaing seriously durable, is also very hard, so it won't flop around like nylon or abs. Stress it enough and it will snap.

But if it doesn't snap on the first bend - then use it, it's fine :-)