Question about newest Blog Article on Waterproof 3D Prints

Question about newest Blog Article on Waterproof 3D Prints  

Active Member

Thank you very much for this very interesting article ( Indeed I am currently working on a projekt where waterproof prints are a plus.
Can you please clarifiy a bit more about your tests results regarding PETG being waterproof or not? Quoting from the blog article "Other tested filaments (HIPS, Nylon, PETG, PLA, PVB) leaked significantly more" and referring to Prusament PETG Information Website ( who states "Because of the very good layer adhesion, the PETG prints are suitable for waterproof applications".
I'm confused about "leaked significantly more" and "suitable for waterproof applications". Or does it really all come down to perimeters and layer height?

This topic was modified 1 month ago by LaForg3
Posted : 01/05/2021 1:58 pm
Honorable Member

I don't think the author reads the forum.

The best place for this sort of question is in the comments section of the blog page.

Waterproofing is mostly a function of how continuous is each layer of filament, the plastic doesn't leak but the structure leaves small gaps.

For some smaller prints, especially those with simple shapes, it is sometimes enough to turn off retraction.  This does have side effects on print quality so you will have to trade off the relative advantages.


Filament Settings > Custom G-code > Start G-code


M900 K{if printer_notes=~/.*PRINTER_HAS_BOWDEN.*/}200{elsif nozzle_diameter[0]==0.6}15{else}30{endif} ; Filament gcode


M900 K0 ; Turn off retraction



This post was modified 1 month ago by Diem
Posted : 01/05/2021 6:14 pm
Active Member


Thank you very much for your answer. I will give the retraction setting a try. Seriously, I didn't know I can comment on blog articles using this account 😀

Seeing Facebook login I left the show (too early).


Posted : 02/05/2021 6:08 am
Dan Rogers
Prominent Member

I can attest to the M900 K0; instruction.  I print fishing lures that need to float and not get water logged after being dragged at  20 fathoms in sea water for an hour.  If you don't turn off LA, you get lures that float for about 20 minutes, then fill with water, and then leach salt for months.  It's fun to see the crystals grow.

But now I do have patterns that I leave LA at default, sink them to 20 fathoms for an hour, and then bring them up.  This effectively infuses salt water into the prints.  Then I let those finish leaching out and then brush off the salt crystals - those are now fresh water diving lures.  The salt adds to the electric field the fish sense - and you get more bites.

But for a flower vase, M900 K0 is fine.  After it cools, hit the inside with a coat of clear acrylic - and you're in business.


Posted : 07/05/2021 5:07 am
Illustrious Member

I was going to say, K-factor, aka linear advance, is not retraction. It's an algorithm for speeding up and slowing down the extruder at corners and intersections to ensure a more even extrusion - reducing gaps or piles of filament at the end of runs. It doesn't change what happens after the extrude stops and begins doing things like retraction or wipes.

Posted : 07/05/2021 8:42 am
Illustrious Member

Interesting that the linked post dismisses another post that is almost identical with the exception of recommending lower layer heights. Both recommend more perimeters, slight over extrusion, and ultimately sealing the prints. 

I have no interest in waterproofing, but this is another instance where something published on the Internet isn't automatically authoritative. I'd try a variety of techniques before settling on any one method. WRT retraction, things that I'd try:

  • Avoid using wiping for smoother tops. Wiping creates those little squishy ends for each layer.
  • Avoid using coasting features in slicers that offer it. Coasting stops extruding before the end of the line to compensate for uneven pressure. Interesting that this is not necessary if using properly calibrated Linear Advance.
  • Not sure why the post focused so much on layer height but not extrusion width. I'd expect that be as important.

No end of tinkering to be done with this hobby!


My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 07/05/2021 5:19 pm
Illustrious Member

Then there's the issue of what "water tight" means. Are we discussing a planter - I printed a few for my plants that hold water fine, without doing anything special whatsoever; or are we discussing a 1500 PSI pressure washer attachment? Yeah - I am considering building a lance adapter for my electric pressure washer ... and yes, I will use an explosion shield when I test it.

This post was modified 1 month ago by --
Posted : 07/05/2021 5:47 pm

Please Login or Register