Basic question on threaded fittings

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esb2000

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I've roughed in a new showerhead and body sprays with brass 90 degree drop ells screwed firmly to framing. I threaded in brass nipples for the body sprays using teflon tape (I noted in other threads that some use pipe dope instead or in addition to the tape). I used a cheaper galvanized nipple for the shower head, since this will be replaced with the shower arm. For my pressure test I capped everything with galvanized caps using teflon tape again.

I tightened the nipples by hand (not very far), then put on the caps and tightened them with a channellock plier. This tightened the threads to the ell as well, but apparently not very well. I got a very slight weep on a couple of these (at the ell in one case, at the cap in another).

(All my sweated connections are fine.)

My question: assuming I disassemble the threaded connections and re-do it with tape and dope, should I put a pipe wrench on the nipple to tighten it before capping? I don't have one, which is why I haven't tried it, and I don't want to use the channellocks since they tear into the brass. (I realize that is a little obsessive, since the nipples will never been seen again, but the channellocks just don't grip very well.)

I saw another post along the lines of "how tight", and I think I understand I'm just not tight enough now.

I guess I'm asking how would you pros do it? I know it seems like a lame question, especially since I've got all the sweated work done right, but I haven't worked with threaded fittings, and I don't want to mess it up and hide it in the wall.

Thanks.
 

Gary Swart

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I hate teflon tape and use only dope, but that's me. When using tape, you must be sure to put it on the right direction or it will just push itself out of the fitting when tightening. Some plumber use both tape and dope. Channel Locks don't give much grip on pipe like a pipe wrench, but be aware that a pipe wrench "bites" into the pipe at least as much if not more than the channel locks. As a DIYer, I would use a narrow jaw pipe wrench as close to the fitting as possible, try to make one grip on the pipe and turn the pipe in without resetting the wrench, and then try to put that part inside the wall. The latter is not always possible, so just make it as unobstrusive as possible.
 

Mikey

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I'm a tape+dope man myself, after going through exactly what you're going through. No matter what I did to some of the threaded fittings, I had leaks. Finally noticed a lot of the HD/Lowe's fittings had "China" molded in them, and scouted around for some Murrican fittings by looking at used building supply places. Most leaks went away, the rest went after using lots of tape and some really disgusting blue dope that gets all over everything. No matter what you use, you're going to have to tighten them really tight.
 

Jadnashua

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From what I've seen, the threads on most of the (cheap) fittings sold in home centers look like the tap or die hadn't been sharpened in years - the threads were more torn than cut. You'll have trouble sealing that kind of fitting with tape...I'd try both, but a good dope, liberally applied should work more reliably. If the threads are really cleanly cut, either should work.
 

hj

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pipe

I use galvanized nipples and caps to test the system, then install the brass nipples when I place the body sprays, using them to tighten the pipes. But you have to realize, that once the body sprays or shower heads are installed, there is no longer the possibility of them being subjected to the same pressure that a capped outlet would have.
 

Mikey

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The tape goes on in the same direction the fitting does, so that the fitting won't be trying to unwind the tape as it screws on. If you hold the pipe with the end facing you, then the tape goes on clockwise, as the fitting does.

Urban myth (maybe): Most children, brough up on digital clocks, have no idea what "clockwise" means.
 

esb2000

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Thanks for the replies, and especially the excellent point from hj, that the pressure will be much reduced in these fittings during actual use. I'm confident I have it right now.
 
R

Rancher

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I've never seen a Left handed NPT thread? Is there such a thing, I want to pumb my entire house that way, just to piss off the next owner and the plumber that comes out to fix the leaks...

Rancher
 

Mikey

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I know they make left-handed dies, but I'll bet there aren't too many left-handed fittings out there. Be sure to let us all know when you sell :D .
 
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