I just did the kitchen sink job from hell. I couldn’t tighten this stuff hard enough to get it to stop leaking, even with five wraps of teflon tape on it. Finally, it dawned on me to take a good close look at the threads, and I found that on the 1/2 NPT close nipples and the 1/2 NPT to 3/8 compression adapters, the crests of the 1/2 NPT threads were cut away. My first thought was, how did I manage to eff these up? Then I looked at some new ones that were still in the original plastic bags from HD. They, too, had the crests of the 1/2″ threads missing, like about 20 – 30%. This creates a long helical channel from inside to outside through which a tiny amount of water will flow.
The good parts of the threads were smooth, but the cut away crests look like the results of a chatter cut on a lathe. Somewhere in China, there’s a machine that’s effing up. So, if you’re going to buy Watts brand brass plumbing stuff from Home Depot, be sure to take a good close look at the threads first.
— J.S.
Replies
Good to see you John !
I've moved those beams you gave me again, from Utah to New Mexico now.
This time I'm going to use them.
Chinese plumbing with problems, say it ain't so ?
There's another BT too, you'll recognize some of the same old faces.
Joe H
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Hi, Joe --
Good to see you're still around. I haven't been doing anything particularly noteworthy in construction until this leak problem, so I haven't been here in quite a while.
-- J.S.
Brass Threads
There's no doubt that the Chinese have come up with some questionable products, but brass threads have some quirks of their own reguardless of where they are made.
Since brass is a soft metal too much tightening is prone to CAUSE a leak by stretching and compressing of the brass, I usually put pipe compound on the threads and about three wraps of teflon tape and tighten up moderately.
There are many studies on pipe threads that have proven that you don't need a perfect thread to have a leak free joint.
Some old time knowledge when we were using brass pipe for water lines in houses we always wraped the threads with lampwick or you had a guaranteed leak in your install..
Lampwick
>>>Hmmm --- lampwick. I've never heard of it. Is it still available? I also vaguely remember something about there being a different thread system for brass, other than NPT<<<
I always got my lampwick from the plumbing supply; whether they still carry it I can't be sure. Any place that carries parts for the old lamps will have it. If you decide to use it you take one sting off the ball, spiral it into the base of the thread, add a coat of pipe compound and you are good to go.(not permitted on gas lines).
Brass like steel have multiple thread patterns, but NPT is the standard used in plumbling systems; if you were trying to mix the types you would have known right away that one of them was wrong.
>>>I did several cycles of tighten and test, <<<
Thats another way that brass gets you, the more you take it apart the more it stretches (this also happens on iron pipe but not to the same extent)
I don't like black Permatex, once you get it on something it's almost impossible to get off; I like Rector Seal #5, luck.
Thanks --
I actually haven't had trouble with brass stuff before this, not that I've used a huge amount of it.
What I do is sweat a 1/2" NPT adapter onto the copper pipe that comes out of the wall. Then I put on a ball valve, and continue in brass to tee off for whatever needs to be supplied -- the faucet, dishwasher, ice maker, etc. That's about all I ever do with brass, because it's so expensive.
I really hate those cheap crappy little water stops that leak and freeze up. I'll pop $7-something for a good ball valve instead.
-- J.S.