Educate me on PLA (and other materials) and water absorption.

[soofle616]

I've seen it posted many times that PLA needs to be stored in an air tight container. Some have even mentioned storing it vacuum packed and/or with desiccant packs, all with the end goal of preventing it from absorbing moisture from the air. Now I'm aware that nylon is a plastic that has a tendency to absorb water from my experience with italian motorcycles and they're frequently plastic tanks so I'm not ignorant that such things really do happen. I do have some questions regarding the effects of that absorption though.

in the case of a nylon fuel tank, water gets absorbed and will cause the tank to swell, often to the point that it no longer looks or fits properly and in extreme cases to the point that mating parts no longer seal correctly and leaks develop. Will PLA printed parts do the same? Will they expand and/or distort when exposed to humid environments? To the properties of the material change at all (strength, rigidity, etc.)?

I'm aware of the printing problems that come with using "wet" PLA but I'm far more concerned about the finished part rather than the raw material. Basically I'm trying to decide if it's worth buying some spools for a couple projects I have in mind or if I should stick with ABS for it's moisture stability. What about the other materials out there for FDM printers. Which ones have moisture related issues?

[ssayer]

Depends on where you live, I guess. In SE Michigan (USA) and in the winter time, I've had a spool out for about 4+ weeks printing on and off with it without a hitch. It prints 1000% better than ABS. If I want to do something for outdoors (at least once I've finished up the ABS that grateful relatives and friends have mistakenly bought me), I'll take PETG any day...

[soofle616]

Thanks, but again, I really don't care about printing issues. I'm far more concerned about what happens to the part AFTER it's been printed.

[ssayer]

You aren't being very specific. PLA: In the house (or at least out of the elements). ABS/PET: Outside...

[soofle616]

My original post asked if PLA specifically and other materials in general will swell/distort or if the material's properties would change, post printing, if it is exposed to a humid environment. Inside or outside isn't really relevant in the context of "a humid environment" but if that level of detail is needed then the answer is both. Some parts will be inside and subject to humidity. Some parts will be outside and subject to humidity. Some parts will be inside AND outside and... subject to humidity. So the question remains if the material will absorb enough moisture to alter the parts appearance, size, or properties when exposed to a humid environment.

[JohnA136]

PLA does not do well outside! It will distort and deform if left in a hot car.

[richardphat]

PLA does not do well outside! It will distort and deform if left in a hot car.

Pretty much, with warm/hot water it is quite fun to twist them.

[soofle616]

That's more the sort of answer I was looking for. Thanks.

[postmahomeson]

pla is a thermoplastic it stands for poly lactic acid ( lactic acid is known as milk acid it's as simple as mixing vinegar and ordinary milk which you can get from the grocery store) , the composition depends on the location wikipedia said" in americain ( north america we use corn starch ) , in asia they use tapioca plant parts such as the roots, chips or starch), the rest of the world uses sugar cane " which is all normally bio plastics which is safer but pla requires complex industrial processes which is said by the same guy as http://green-plastics.net/posts/76/q...astic-project/ , ) but it's actually making vinyl ester which is a plastic based off of carboxyl acid which is found at #.http://en.wikipedia.org/wiki/Carboxylic_acid/ which uses animo acids ( which is the enzymes just like those found in plants and animals including fatty acid aka lard) 2-furoic acid (c5h4o3) vinyl ester can also be seen as a sacred plastic because the 2 - furoric acid which part of the word chemically sounds like a fluoride which it's is like a fruit of spirit , spirtually fertitle , enriched with grace oil aka olive oil which is like a magic tonic , and vinegar made of mother of vinegar a mother of grace which is havens wife ( the kings and queens sworn on all life aknowlegements because they are possessors in this case the good guys but the undead risen permethus of greece the possesor of the devil has also mentioned it but it could be ether and to stop the bad guys from eliminating the element of peace there's a symbol it uses the tao cicle with a orbit called the amulet of revoltution of the satellite of the sky of spirits to protect the earth and it's protection against a univeserial post industrial dark age ( which i do not know why heavens wife not in the bible ) the vingear in vinyl ester is a symbol a heart of love of spirtiual contact terminal passage to ward off evil , and a conductor of the energy of spiritual contact it's perfect for amulets and idk why it's not used in the ancestor 3d print thing i think that's what your Probbaly looking for eh

[3DPBuser]

PET might be best:

http://3dprintboard.com/showthread.p...ighlight=smell