FDM water/air tightness

qbazdz

qbazdz

qbazdz

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Joined
27 Oct 2009
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Location
West Sussex
Hi,

I wonder what people do here if they want their FDM prints to be water or air tight? I've resulted to 'painting' a thin layer of 2-part epoxy which sort of seeped into the print, but this is a bit messy and end result very much depends on your skills and epoxy used. There must be something easier/better surely?

Thanks
 
I have no experience with 3D printing but a number of YT hobby scenic creators use builders instant grab (no more nails type stuff) to join FDM parts together. Must be a few on the market that waterproof given the jobs they are used for.
 
I've printed a self-watering plant pot recently out of PLA and it appears to be completely water tight following 2-weeks of testing with water in it and nothing else. Think the trick there is to increase the number of walls.

Another thought; Acetone and vapour smoothing with ASA/ABS. I've not used this for water tightness but have experimented and used it for some projects. Acetone slurry is great at glueing ASA (and ABS) parts together which creates an incredibly strong bond because it melts the material together. Acetone vapour smoothing effectively melts the outer layer of the part to make it smooth which I'd imagine would also improve the air/water tightness of the part too. You could in theory brush the acetone on also and likely achieve the same results but the finish won't be as pretty and if it goes on thick, you might find it continues to melt the material for longer than you expect! For vapour smoothing, Vaseline is great if you want mask off part of an ASA/ABS model so it doesn't get smoothed. Easy to apply and easy to wash off after. If you try this, just make sure you're setup with a mask and gloves in a well ventilated place. Acetone isn't great to breathe in.
 
I’ve not tried air tight but I have printed a couple of jug type things for bailing out cnc coolant, they mostly are used to top up water levels in our tool room but they are watertight.
They aren’t delicate at all, 3-4mm walls all solidly printed with I think a .2 layer height….cant remember but it was either .15 or .2.
 
Might be worth taking a look at this (I've not spent much time reading about it, it's something I bookmarked a few months back because people were saying about air / water tight possibilities and sounded interesting) :


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www.reddit.com
 
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Thank you for the input.
I definitely had issues with one of the parts leaking air, but this was a component for a simple vacuum connector that was hooked up with a syringe to generate it and it leaked easily. I couldn't get more walls due to size in so perhaps that was the culprit.
 
cokecan said:
I've printed a self-watering plant pot recently out of PLA and it appears to be completely water tight following 2-weeks of testing with water in it and nothing else. Think the trick there is to increase the number of walls.
Click to expand...

PLA generally not the best if it is exposed long term to outdoor weather conditions - especially heat cycles will start to warp it and combined with long term exposure to moisture will start to lose integrity. Some of the cheaper PLA I've used does not stand up to long term submergence in water at all unless coated in some way.
 
Rroff said:
PLA generally not the best if it is exposed long term to outdoor weather conditions - especially heat cycles will start to warp it and combined with long term exposure to moisture will start to lose integrity. Some of the cheaper PLA I've used does not stand up to long term submergence in water at all unless coated in some way.
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100%, PLA is not for outdoor use no matter what anyone says. This is an indoor plant pot for my desk :) should have specified. Generally anything I do that gets exposed to sun or outdoor weather is in ASA.

Just in case anyone was interested lol
54663355181_246f48d615_b.jpg
 
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qbazdz said:
Outer shell is PLA too? Nice finish you got there!
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Yeah it's Bambu Matte PLA (Dark Green and Charcoal). First time I've used the Matte stuff and it turned out well. Definitely printed differently to the Bambu Basic PLA for me. Was fully expecting to just use my Bambu Basic PLA profile I have tweaked but had to make some changes for this to print consistently well (flow rate, bed temp etc). This model was just from MakerWorld
 
if you really want it to be water tight then give it a couple of coats of mod podge and let it dry fully.
I've had more than one print seem water tight for a few weeks......
 
unless you are doing a vasemode print with just one layer prints should be water tight.. Depending on geometry and number of walls.
 
Yes a clear gloss lacquer spray is what I use if I want air or water tightness! Easy to apply and dries in 15mins!
 
Just had an epiphany lol and actually tried this - if you have any leftover SLA resin, could use that and put on for a quick UV cure :D
 
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