Trick to Threaded Washer Valves?


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Old 01-27-14, 12:43 AM
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Trick to Threaded Washer Valves?

Both brand new valves of my washer box leak where they connect to the female adapters I sweated on before I connected the valves to the adapters. I initially connected them with a moderate amount of torque, but when it was obvious they leaked I tightened them progressively more until another full turn of the valves (so they point forward in the end) just isn't in the cards. I'm so frustrated I'm prepared to ditch the valves (and washer box, if necessary) and get valves I can sweat directly on. They can put a man on the moon, but why can't they make washer stop valves that seat reliably? Have others encountered this problem? Is it something I'm doing wrong?
 
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Old 01-27-14, 05:19 AM
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I feel your pain. I hate NPT fittings especially when you have to get a valve or tub spout aimed in the right direction. Did you try removing the valves and apply more wraps of Teflon tape? I know tape does not technically seal the fitting but it can help.
 
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Old 01-27-14, 08:46 AM
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hi Riddler –

I always just keep track of how much Teflon tape I put on, and then if it leaks, then back out and start over varying the amount of tape. You should be able to get the valve orientation proper and really tightened up at the same time. A lot of times it is trial and error with me.

I have heard many times that many plumbers like to use Teflon tape and pipe dope at the same time. I’ve been doing that with great success. I coat some RectorSeal #5 on top of the Teflon tape, tighten up the connection really good, and no longer have leak problems with threaded connections.

Good luck!
 
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Old 01-27-14, 09:25 AM
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Something is wrong if a reliable seal is dependent on how much teflon tape one uses. Tape and pipe dope is only supposed to preserve the threads for easy removal.

I have one more dumb question. Are the valves sweatable even though they have threads? In other words, are you supposed to be able to insert 1/2" pipe into the ID and sweat in, while the threaded OD is available for Pex connections? I'd like to know if that's a possibility before I tear into it again.
 
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Old 01-27-14, 09:35 AM
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I agree. Getting a seal should not depend on tape. Unfortunately NPT is a tapered thread with no specific or dedicated sealing surface. If just relies on cranking down until the threads are pushed together hard enough to not leak. In a perfect world that's OK but when dies and taps wear they cut different profiles so some can be a real bugger to get to seal.

Some hose bibs can go both ways; NPT and sweated. It just depends on what spigots you have.
 
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Old 01-27-14, 09:49 AM
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I have bought galvanized pipe fittings so out of spec they wouldn't seal even at the lat thread. Regardless of dope and/or tape. Made in China from Bigbox. You could actually hand thread them on almost all the way to the last thread but a good fitting you should not be able to hand tighten them more then a third of the way. Not a fluke. Encountered the problem several times till they started buying from Thailand. Till then I had to stick to supply houses and hardware stores that carried American made... at three times the price. Not saying it is but maybe it is the valves or adapter are out of spec.
 
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Old 01-27-14, 04:46 PM
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hi again Riddler –

In other words, are you supposed to be able to insert 1/2" pipe into the ID and sweat in, while the threaded OD is available for Pex connections?
That is my understanding. I think this is one like that:

Washing Machine Outlet Boxes

The only thing is, I think that some valves can be somewhat more difficult to sweat, for me anyway. Seems like those heavy brass valves need a lot of heat. I use a MAPP torch and it made sweating valves a lot easier. I think you would have to be careful and figure out some way not to melt the box.
 
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Old 01-27-14, 05:14 PM
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Riddler thought you might be interested in this.

I think tape/pipe dope really is needed as a sealant. I have heard smart people say that it’s just a lubricant that allows you to tighten easier, but anytime I’ve done a search I’ve found things like the following:

from FineHomebuilding.com -

…Teflon tape and pipe dope are used to fill voids between male and female threads to make joints leakproof and to prevent metal parts from rusting together. ..
from Wisegeek.com -

…The plumber's tape that is more properly called Teflon® tape is used to seal pipe threads against leaks. It is a thin, white tape that fills in the gaps between the pipe threads and also acts as a lubricant for the pipe threads when tightening the fittings together. This type of tape is not adhesive and cannot be used to stick items together…
I guess as was mentioned in the other posts, since the threads are more or less imperfect, there would always inevitably be gaps? I guess? LOL
 
 

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