Water tight threads not working correctly

[ymmallik]

I have tried to make my threads watertight, but it's not working.

First, I 3D printed my simple container with threads.

Second, I put a liquid/water inside

Third, I flip the container to see if it leaks 

Issue: It leaks when I flip the container 

[wersy]

Do you mean the screw cap is not tight?
In that case, I would use a gasket, just like you do with screw caps in metal.

[ymmallik]

I would say that the screw cap is pretty tight. I have also seen some water bottles use a similar design without a gasket, so I'm trying to avoid buying a gasket

[wersy]

There are conical sealing threads.
As a printed part, it will hardly achieve the quality it needs to seal.

[CGBenner]

@ymmallik 

Hello and welcome!

I have very little experience with 3D printing, but enough to know that threads are very challenging.  Could you share some information about the printing process?  What kind of printer, and what filament material?  Print settings?  Several variables could lead to under-formed threads or threads that simply will not be watertight.

I also agree that using tapered threads, a gasket, or taping the threads (or all of these) might help.

[HughesTooling]

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@ymmallik wrote:

I have also seen some water bottles use a similar design without a gasket, so I'm trying to avoid buying a gasket

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Water bottles I've seen normally seal on the end face not the thread. Even using metal you'd use PTFE tape or loctite to guarantee a good seal because there's normally clearance at the major and minor diameters.

Even when the thread is tight there is a helical gap that will leak. You might get a seal if you have a narrow annular rib on the cap to seal on the end of the container.

Mark

[ymmallik]

thank you, i will try that for sure!