Closed loop is leaking

[Octoberfest]

I'm in the process of putting my tank together and building a closed loop. I'm using threaded bulkheads and screwing a PVC fitting into the underside of the bulkhead. Well the 1" PVC threaded union that I screwed into the 1" bulkheads seemed to fit really loose. I could easily spin them all the way to the stop in the bulkhead. I added Teflon tape and still the same result, threaded really easy.

I just figured this is the way it would be and went with it. Well obviously you can bet that I had water leaks"¦at each one of these. I removed them and added more tape"¦still had a leak at about 1 drop per 10 seconds.

I'm at the point where I'm ready to cap the holes and just go with powerheads. Anyone have any ideas on this? One suggestion I've gotten was to put silicone on each union before I screw it into the bulkhead"¦but this doesn't give me a warm fuzzy.

 

[RVANANO]

That's odd. They should be really tight even without tape. They should screw on a few threads by hand and then require some real force. Any chance you got metric & standard for the male/female?

 

[Octoberfest]

The bulkheads are 1" NPT (National Pipe Thread). I'm goign to remove one tonight and bring it to the hardware store and see if they have a union/unions that are a tighter fit.

 

[Palting]

If you can't get a tight fit, you can use silicone. It "seals", but does not "bond" like PVC glue would. One other option is to get new bulkheads.

 

[jacksonpt]

Use teflon grease, not teflon tape. I'm not sure if it will help with your problem as it sounds like the fittings don't fit well with the bulkheads, but with threaded fittings in general teflon grease is a better/easier seal than the tape.

 

[tmc1313]

You can always glue them in and then adjust the bulkhead to the angle you need the fitting to be. I've done all of mine like this and never had any leaks. I had a couple of 1/2" threaded that seemed loose, I glued it and never had a problem (3+ years now).

 

[dkh0331]

The bulkheads are 1" NPT (National Pipe Thread). I'm goign to remove one tonight and bring it to the hardware store and see if they have a union/unions that are a tighter fit.

:thumbsup:

If you are able to remove and take it to your hardware store, that would be great.

 

[mgraf]

thread seal, pipe dope. Seal it right up

 

[d0ughb0y]

unions have female threads. are you using the outer threads of the bulkhead to connect the threaded union?
you can only use the inner thread of the bulkhead. the outer thread is only meant for the bulkhead nut only.
You can get special bulkheads where the outer threads are compatible with female pipe thread. I ran into this situation also when I was setting up my closed loop. glass-holes helped me get the correct bulk head and the correct fitting to connect to the outer thread of the bulkhead.