Teflon tape not sealing. What else will work?

[b4tn]

I have had a busy weekend and had to sideline the project but I will be back at it tomorrow. For all the questions. The elbow is a barbed 3/4" NPT nylon fitting. The bulkhead is an BRS 3/4" ABS. if I could find a a pvc fitting that was both a 5/8" barbed end and elbow I would have but that's all I could find and all of the nylon NPT fittings fit the same in all the bulk heads I got so I know it's not a defect. I am going to get some Teflon dope tomorrow and try that. If that doesn't work silicone it is.

 

[AZDesertRat]

Go to Ace or True Value, they have store branded LaCo PVC thread lubricant sticks, not paste. I have found the sticks at some Lowes and HD in the natural gas fittings section but it's hit and miss with them.

 

[Amphibious]

There is nothing wrong with teflon tape AS LONG AS IT IS APPLIED CORRECTLY. Correct application is to hold the fitting in your left hand with threads pointing toward your right hand. Next, hold the tape in your right hand with the tape coming off the bottom of the spool. Next, lay the loose end over the top of the threads and hold it in place with your thumb, then begin your wrap overlapping the the tape. Make multiple wraps, minimum 4 to 6. If you follow this procedure and you find it leaks, remove the fitting and put more teflon over the original.

I'm a retired pipefitter (40 years and retired 15) and have been piping aquariums for more than 60 years, never had a teflon taped fitting leak. Apply it right, wrap it on thick, hand tighten plastic fittings, never use a wrench. It's plastic, it will crack and leak.

Dick

 

[Furiousreefer]

applied an amout of silicone on the threads, as you tighten. The silicone will seal it-self. Let it sits 24hr before use. Silicone is very durable and easier to remove.

 

[cjd]

PVC primmer / glue (permanent) .... Teflon tape wrapped in the same direction you screw the fitting in other wise when you screw the fitting in you unwrap the tape as it goes into the fitting causing leaks!

 

[NeptuneGarden]

Well, I'm not a fan of any of these fixes since they are all band aids for improperly installed bulk heads.

Have you thought about turning the bulk heads around so that the threaded part of the bulk head is in the dry area like it is supposed to be installed ?
It wont look as pretty but it will seal properly without glues/silicones or any other jimmy rigged patches.

Also bulk heads on a round surface always have trouble sealing and staying sealed for the long term.

I much prefer using a Uni-Seal plug on non flat surface and just pushing a pipe directly through it. No bulk head required. It will seal perfectly and last a life time.
Uni-seals are very effective, inexpensive, and much overlooked tool in the aquarium world.

http://www.usplastic.com/catalog/item.aspx?itemid=89951

 

[b4tn]

The bulkhead seal itself is not whats leaking, It is actually holding water just fine. Its the nylon fighting threads that are leaking. I am going to pick up some teflon paste tonight.

 

[b4tn]

I also have PVC to ABS transition cement that I have used to glue the PVC pipes to the ABS bulkheads. Does anyone know if transition cement works with Nylon?

 

[NeptuneGarden]

The bulkhead seal itself is not whats leaking, It is actually holding water just fine. Its the nylon fighting threads that are leaking. I am going to pick up some teflon paste tonight.

The threads are not sealing because they were never meant to seal ...... the threads are supposed to be dry. Any "fix" you try will eventually leak over time.

"For the long term" was the key part of my statement on the bulk head itself leaking.
Flat seal on a round surface.... not good.

Uni-seals FTW ! I love uni-seals for stuff like this.
I'm a strong believer in using the right tool for the right job .......

 

[cjd]

The threads are not sealing because they were never meant to seal ...... the threads are supposed to be dry. Any "fix" you try will eventually leak over time.

"For the long term" was the key part of my statement on the bulk head itself leaking.
Flat seal on a round surface.... not good.

Uni-seals FTW ! I love uni-seals for stuff like this.
I'm a strong believer in using the right tool for the right job .......

Uni - seals are a great option for installs like this .

 

[TherealplexiG]

More Teflon

First, teflon tape was never intended for use on plastic fittings. This product is for metal pipe threads, that without lubrication will gall. This of course damages the fittings, and prevents a good seal.

Second, the leak "channel" in these fittings is at the vertex of the "V" notch, and no amount of tightening will close this small gap. Third, the greatest stress in these fittings is along the pitch diameter (centerline of the interconnected peaks and valleys.)

 

[Todd A.]

Neither Teflon tape or pipe "dope" are intended to "seal" joints, no matter how they are advertised. They are there to lessen the friction between the two mating threads so they don't bind up on each other. And as mentioned in the first thread (no pun intended), NPT threads are tapered so that they seal together without the use of gaskets, O-rings or compression ferules. IMO, replace the fittings cuz even if you stop the leak now, there's always a chance it will come back later.

 

[TherealplexiG]

Lowes sells teflon paste. you can put it on as thick or as thin as needed. it can be a bit messy though

Teflon is a solid plastic; therefore what I believe you mean is Teflon powder in a carrier! The sealing would be accomplished by the carrier/paste. Yet, the Teflon still imparts the lubricity that can assist over-tightening!

 

[AZDesertRat]

Read and follow the directions in the bulkhead installation tips sticky thread, it has helped thousands of reefers in the same situation.

 

[DurocShark]

BRS sells Uni-Seals too.

 

[john.m.cole3]

Read and follow the directions in the bulkhead installation tips sticky thread, it has helped thousands of reefers in the same situation.

I think many members post before reading the thread in its entirety. My next build will be all with threaded PVC and I WILL be using the LaCo Plasto Joint Stick. Thank you for all of your contributions @AZDesertRat

 

[b4tn]

I couldn't find it local anywhere but was $4 and change on amazon.