Tough PLA and saltwater

[Rocket 1]

Hello all.  I have some parts that will be submerged in seawater for 24hrs.  Does anyone think Tough PLA would be inappropriate for this?  Does it absorb much water/dissolve/change properties?

 

Thanks in advance!

[Smithy 1,136]

I have no experience, but I think it also depends if the part is only used for 24hrs and after that you throw it away or if you will use it afterwards also. 24hrs in seawater should be no problem I think - but I only guess!

[P3D 46]

Judging from the very mixed experiences that turned up on a quick web search on this issue with pure PLA (ranging from "will crumble in no time" to "absolutely no problem") it seems to depend very much on the exact composition of the PLA filament.

If you can't test and want to stay on the safe side, CPE or a similar material (XT, NGEN, generic PETG) would be the way to go IMHO - at least if it is pure salt water, with chlorinated (swimming pool) water it can be a different story, judging from the chemical resistance charts I found for PETG.

[Rocket 1]

Thanks.  I guess I just need to print a part and submerge it....CPE is probably the way to go, its just I'm very new to 3d printing and like being in my comfort zone of plug-n-play with tough pla and an S5...

[geert_2 556]

I have no experience with tough PLA, but from standard PLA (Ultimaker blue) and PLA/PHA (colorFabb) I have made sifts which are sitting in the drain of my laboratory tables. In one year they got a little bit duller, but they did not decompose (what I originally expected) and did not crumble apart (what I also expected).

 

So if only for a short time, I wouldn't expect any problems.

 

If you have sea water available, just make a couple of test prints and let them sit in it. And give feedback, so we also know.  :)

 

 

[Rocket 1]

For the record, in case anyone is interested, I had the Tough PLA in seawater for a week and no problems.

[Smithy 1,136]

Thanks for the information and reporting back!

[geert_2 556]

On 11/1/2018 at 5:28 PM, Rocket said:

For the record, in case anyone is interested, I had the Tough PLA in seawater for a week and no problems.

 

Yes, feedback on the life of materials is always very welcome. Thanks.

 

If you would have the opportunity to submerge models for a longer time, preferably of different materials, I would suggest you do so.

 

PLA is supposed to be bio-degradable, it should decompose into lactic acid and then further into CO2 and water, but I think it will take a long time before it completely vanishes. A big unknown is at which point it becomes too brittle to be functional?