I have a piece of test equipment that needs to stay underwater for days. Normally I would use or make a waterproof case with a lid and a gasket.
Instead, I’m wondering if I could print a box, pause the print just before the top face, put the device inside and then print the top face over it. No openings, no nothing, and the device works by induction so it doesn’t need to physically connect to anything.
But this would only work if 3D-printed PLA walls are really waterproof. After all, 3D-printed features are kind of a bunch of wires more or less loosely attached to each other, so I wouldn’t be surprised if water could leak through under pressure.
Before I spend any time assessing this myself, has anybody tried printing waterproof enclosures?
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Sometimes a regular manufactured item is better than a 3D printed object. Just use an old tupperware container
Look at the big spender over here. That’s what the spaghetti stained margarine container is for.
Even a ziploc freezer bag might work.
The guys from Prusa Research have a lenghty blog post about watertight 3d-prints: https://blog.prusa3d.com/watertight-3d-printing-part-2_53638/ This might be a good source for tipps and tricks!
I myself have made a couple of very simple watertight (non essential) prints for scubadiving. They are holding up really well!
I am interested in it. What are you making for scubadiving that needs to be waterproof?
Mostly covers for different hoses and valves for scientific instruments used underwater. For the seals I mostly use O-rings.
Thanks! Well, I was kind of hoping to throw something on the printer and have a working system without too much work. But it looks like achieving proper dependable watertightness might be a whole side project of its own.
I think I’ll just order the proper ready-made ABS case and wait until it arrives, most likely.
But it looks like achieving proper dependable watertightness might be a whole side project of its own.
This is the case, especially if you want watertight prints right off the printer. Post processing (eg coating, smoothing, etc) are another approach. Post processing also seems like it would be more consistent print to print.
3d extrusion prints have microscopic holes inside, it’s porous. I wouldn’t trust it depending on the application. You can seal the outside and they also sell additives to lessen the effect (here’s a video about it: https://m.youtube.com/watch?v=Q8x-mjjT8j4) but casting resin might be better (haven’t tried). Resin printing doesn’t have these problems from what I understand but ou can’t really stop the print midway.
Fiberglass, if the object isnt complicated to make, would be the best option in terms of quality. Bending and cutting pvc sheets into a box then soldering is also an option. Soldering pvc and rolling fiberglass isn’t really difficult but they both require specialized tools/materials. Getting pvc pipes and soldering end caps would probably be the easiest.
How robust you need to make it largely depends on pressure and depth.
I’ve played around with using PLA to make plant pots on an old Ender 3. It wasn’t quite waterproof, but pretty close. If you wanted a perfect seal for underwater shenanigans, I’d probably experiment with different wall thickness settings, and maybe temperatures/fan cooling settings. You want to try and minimise the tiny air pockets between layer and filament drawing lines. (Resin 3D printers are probably better at this tbh.)
I had reasonable success using a hot air gun to melt the outer layer of PLA to make it perfectly smooth, but this can deform your object if it heats up too much, so I’m guessing very hot temperatures and less contact time would be the ideal setting.
You could also try smearing Vaseline or resin coating the outside of the object.
So what you’re thinking… Then coat it with epoxy.
If it’s non-critical, with a bit of work it can be made ‘waterproof’, at least at 1atm. But realistically, unless you need a specific shape, it’s going to be easier and more reliable to just use an off-the-shelf case.
Haven’t tried it myself, but have heard in passing that they are generally not waterproof. Might be different for different materials or print orientations though?
Or you can do some post processing, add a coating, or vapor smooth?
I made a small planter and I sprayed it with some sort of clear sealant for extra measure and it has never leaked.
For you, under pressure might leak after a little while, but you could put some sort of sealant on it to have more faith in it. It depends how long you want it under water, but it should be at least a little water-proof by itself.
Sorry no better experience than that
I’ve done the same. I put on a single layer of clear coat and it has been perfectly water tight.
I think with a sufficient wall-thickness your box would be waterproof. If I were you I would test it first by printing a small box like you described you would, and put a piece of paper with ink writing inside. Then submerge it into water for a few hours. After that, let it dry thoroughly and saw it open to see if the paper inside has gotten wet or the ink writing has been smeared/diluted.
I do not 3D print, but i do have some basic knowledge of it? I am not a
lawyerprinter, YMMV.I have heard that some materials can be smoothed over using acetone vapour; what about wiping the finished print to smooth over open pores on the surface of a print?
Alternately, since it’s not a flexible material what about applying something like 3M never wet?
How big of equipment? A ziplock freezer bag might do the trick for you, or if you’re fancy, vacuum seal it. I trust that to sous vide meat for days, at elevated temps even.
What is the sensor sensing?
It records temperature and EM radiation. We have a customer that has EMC requirements for underwater equipment 🙂 I mean as long as they pay eh…
The device is maybe 4" x 3" x 3" - possibly longer on the long side - and fairly expensive. The ziplock bag thing may work but it looks sketchy considering the price of the thing.
Just spit balling here. Maybe put your sensor in a ziplock or vacuum seal it and then put that inside your 3D printed box that way you get all the security without the jank look.
A vacuum sealer would be more robust and look less janky than a Ziploc bag. You can get a used food saver for cheap!
How deep? Pressure might be a problem? (I’m curious if this is a documented spec, and which one it is. I’m very curious)
Not very deep. About 3 ft.
Of course it can be.
Will it be on your setup though?
Bump temperature to make better adhesion, lower the speed. Then try it out!
Also if you can’t make it perfectly watertight, check out why and try to remedy it. Maybe post printing! You can put glue, paint, depending on why it leaks, chuck it in the owen to melt it a bit…
But first of all, try it out!
Good luck!
In my experience, TPU is fairly easy to make watertight. You have to start with good and dry material so it prints as smoothly as possible. It floats pretty easily though, so you might need to print it solid or with high infill.
A couple of months ago I printed a bird bath out of PETG which has been watertight so far. I used three outer layers.
It’s the number of walls you print that will determine just how long the box will hold the water in or out. I find 4 walls to be about as water tight as I need. But I’m not sealing anything valuable either.
Edit to add: This would be an excellent need for that brick layer printing to be used. The offset layers would provide far better sealing than the standard layer method we commonly use.
From experience printing a bunch of different planters with varying settings and printers, without post-processing/sealing the answer is “not reliably”. You can increase your chances by using many perimeters and surface layers, high heat, and thicc extrusions, but you are still just stacking swiss cheese slices on top of each other hoping the holes don’t line up.
With days submerged, even the tiniest of defects means water can and will seep in.
Have you tried https://github.com/TengerTechnologies/Bricklayers yet?
I think this might improve watertightness considerably as in the tests it increased layer adhesion/strength by quite a lot.
