Need Help With Leaking Threaded Joint

[Tumbleweed]

Good day. I have this threaded connection that still leaks. This is a John Guest MPT plastic adapter threaded into a stainless steel street elbow attached to a sediment filter. First I tried using the standard (white 1/2" wide) PTFE. Water droplets formed under the lip at the female end of the street elbow. Leads me to believe the water is tracking the stainless steel thread. The local plumbing house suggested I use a Gray PTFE for Stainless Steel fittings, as it was thicker. With the Gray tape, the water now appears at the start point of the tape wind, as if the water is tracking the adapter's threads under the tape. My winds are always clockwise starting higher on the thread, overlapping by 50%, and working towards the end. I am leaving the last thread bare to make it easy to start the thread into the female end of the street elbow. I have tried 2-layer wraps and 3-layer wraps and have not found a remediation to the slow drip. Slow drip being droplets appearing about every 90 seconds.
Before I discard the John Guest adapter and solder up a length of 1" dia. copper to a MPT Adapter as a substitute, I wanted to get feedback in case there is something I am missing ? All feedback, responses, and recommendations are welcomed. Thank you in advance, David.

 

[Geofd]

try white teflon paste long with the tape

 

[Jeff Handy]

Your adapter might also be cracked.

 

[GReynolds929]

The JG male adapter doesn’t look like its threaded in very far, are you going just hand tight, or putting a wrench on it to seat it?

 

[DFBonnett]

If that galvanized street el is from Home Depot, the threads may be cut wrong. BTDT, also with a water filter.

 

[CT18]

Plastic into metal is always a difficult situation, stainless is even worse. Try a brass street ell or go metal to metal and get rid of the plastic adapter. Did you try adding pipe dope on top of the teflon tape

 

[Tumbleweed]

The JG male adapter doesn’t look like its threaded in very far, are you going just hand tight, or putting a wrench on it to seat it?

Appreciate the feedback. To respond to your questions, the adapter has a long (1 inch) threaded section, and is into the stainless steel street elbow half an inch. It is tightened down tightly via a 10 inch crescent wrench. Any tighter and I am concerned for snapping the adapter. I’ll keep at it.

 

[SHEPLMBR]

Why not just get a metal nipple?

 

[Tumbleweed]

If that galvanized street el is from Home Depot, the threads may be cut wrong. BTDT, also with a water filter.

Good point. The street el is stainless steel and from the local plumbing supply house not the big-box store. I have another ss street el on the other side. It has a 2” nipple threaded in and sealed easily with just over half a rotation past hand hand tightening. I thought about swapping the el’s but didn’t want to take apart a perfectly good connection and end up introducing more issues.

 

[Tumbleweed]

Plastic into metal is always a difficult situation, stainless is even worse. Try a brass street ell or go metal to metal and get rid of the plastic adapter. Did you try adding pipe dope on top of the teflon tape

great point, first step for today is to retape and apply some Tplus2 I picked up late yesterday. If I still don’t get a seal I plan to solder up a mpt-adapter and short length on copper pipe. Good point about trying a brass street elbow before breaking out the torch. Thanks.

 

[Jeff Handy]

Why not just get a metal nipple?

It looks like the nipple has different sizes on each end, not just a regular nipple.

 

[Tumbleweed]

Why not just get a metal nipple?

The other end of the push-to-connect corrugated stainless steel line has a clack fitting to connect to the water filtration tank. Changing over to a nipple at the elbow would also require placing a special order for a new section of corrugated ss with FIP and Clack ends. Trying to get this working assuming I just overlooked something simple. If I don’t get the plastic adapter to seal to the ss street elbow by using some thread paste, I will break out the torch and add a mpt adapter to short length of copper pipe and use that instead of the adapter. Appreciate your response.

 

[Tumbleweed]

It looks like the nipple has different sizes on each end, not just a regular nipple.

Correct, one end of this nipple?/adapter is male threaded, the other end is a male John Guest push-to-connect to accept the female JG p-t-c end on a length of corrugated stainless steel tubbing. Happy to provide the clarification.

 

[Tumbleweed]

Thanks everyone, I’m off to try the thread dope at this time.

 

[Tumbleweed]

Issue solved, put thin coat of Tplus2 thread sealant on adapter after applying fresh PTFE tape and the ”tears” stopped dripping. big thank you to everyone that responded with questions and recommendations.

 

[Jeff Handy]

Fyi, when I am re-doing a fitting with a tiny leak like this, I always rub a thin coat of teflon dope into the female threads with my little finger or a flux brush.
Maybe not necessary, but it works for me.

 

[Tumbleweed]

Fyi, when I am re-doing a fitting with a tiny leak like this, I always rub a thin coat of teflon dope into the female threads with my little finger or a flux brush.
Maybe not necessary, but it works for me.

Thank you Jeff. I am always happy to lean new tricks and tips. Wish I had found this forum when I bought my previous residence.