Plumbing question

I figure someone on here knows the answer to this.

I had a leaking hose spigot that couldn't be serviced any more as it was too corroded. I soldered on a threaded fitting and screwed in the new spigot and valve with Teflon tape on the threads. The problem is that I have a very slow leak from the threads. I replaced the tape once and it didn't make any difference. Should I use pipe dope instead? If so, how long would the water have to be off for the dope to cure? I've only ever used this on gas pipes.

Perhaps we need a plumbing section?

What I normally do at work, and this can be for compressed air, water or pressurized oil, is use pipe dope and then wrap it with some tape. First off, use good stuff. As for the dope, I don't use the generic stuff you can get at Lowe's or Home Depot. Go to the auto parts store and get the Loctite sensor safe stuff. It's the best stuff out there for this. Then just do a couple wraps of tape and finally a thin film of more sealant so that you have threads-sealant-tape-sealant-threads. Should be able to use it almost instantly but if it makes you feel better give it 10-15 minutes to set.
If that leaks, you have a problem with your threads somewhere. If that's the case, your next step is more Loctite. I forget the number but it's "gasket eliminator". It's basically an anarobic epoxy. Clean the snot out of both sets of threads, including using brake clean to eliminate residue. Apply a bead around the threads and fill in with your finger. You want the sealant to just fill in the thread recesses. Install your spigot and give it five minutes and it should be ready to use.

73 Mike said:

I figure someone on here knows the answer to this.

I had a leaking hose spigot that couldn't be serviced any more as it was too corroded. I soldered on a threaded fitting and screwed in the new spigot and valve with Teflon tape on the threads. The problem is that I have a very slow leak from the threads. I replaced the tape once and it didn't make any difference. Should I use pipe dope instead? If so, how long would the water have to be off for the dope to cure? I've only ever used this on gas pipes.

Perhaps we need a plumbing section?

Click to expand...

You may have overheated the copper fitting and annealed it. I would just unsweat it and sweat another fitting on it, a 2 minute job.

clutchdust said:

What I normally do at work, and this can be for compressed air, water or pressurized oil, is use pipe dope and then wrap it with some tape. First off, use good stuff. As for the dope, I don't use the generic stuff you can get at Lowe's or Home Depot. Go to the auto parts store and get the Loctite sensor safe stuff. It's the best stuff out there for this. Then just do a couple wraps of tape and finally a thin film of more sealant so that you have threads-sealant-tape-sealant-threads. Should be able to use it almost instantly but if it makes you feel better give it 10-15 minutes to set.
If that leaks, you have a problem with your threads somewhere. If that's the case, your next step is more Loctite. I forget the number but it's "gasket eliminator". It's basically an anarobic epoxy. Clean the snot out of both sets of threads, including using brake clean to eliminate residue. Apply a bead around the threads and fill in with your finger. You want the sealant to just fill in the thread recesses. Install your spigot and give it five minutes and it should be ready to use.

Click to expand...

I see you are a dope tape dope guy, LOL. It is funny how one plumber or pipe fitter is d/t/d another t/d, yet another d/t, and they all seem to work .

Thanks guys. I'll try the dope sandwich first and if that doesn't work, I'll replace the fitting.

Ozzy, funny you mentioned that. I've delt with lots of plumbers but I'm not actually a plumber. For the last 12+ years I've worked on compressors and air systems. So I have a lot of experience with sweating copper and threading pipe, but none of it from books or classes. My "technique" all comes from that background and I have just found what works best for our application. I can tell you that for the most part if I can get 200* oil running at 125psi to seal, I generally don't have a problem with water. As for the annealing, I'm not even sure what that is but I'll bet I've done it before! More than one fitting I've overcooked and had to throw away.

clutchdust said:

Ozzy, funny you mentioned that. I've delt with lots of plumbers but I'm not actually a plumber. For the last 12+ years I've worked on compressors and air systems. So I have a lot of experience with sweating copper and threading pipe, but none of it from books or classes. My "technique" all comes from that background and I have just found what works best for our application. I can tell you that for the most part if I can get 200* oil running at 125psi to seal, I generally don't have a problem with water. As for the annealing, I'm not even sure what that is but I'll bet I've done it before! More than one fitting I've overcooked and had to throw away.

Click to expand...

If you anneal copper it becomes soft. Overheat a copper fitting adapter and it looses its "elasticity" .

As you know pipe threads are tapered, and as they make up the taper causes an increase in pressure on the fittings. It is that pressure that makes the seal. Anneal the fitting and you get a leak more times then not. At that point it takes either a "glue" or a new fitting to rectify the problem.

I was a millwright for 30 years before I started doing this pipefitter/plumber gig. I have made up hundreds of hydraulic system fittings at 3500 psi without a leak, and had my butt kicked by a 3/8" copper compression fitting :rofl:

Since it's dark by the time I get home, I haven't had a chance to try either fix yet. I do have a question on replacing the fitting though. Easy enough to figure out how to remove the old fitting. Just heat it until the solder is soft enough to remove the fitting and pull it off (remember to wear gloves :tomato. What's the technique for putting on the new one? Do you flux the inside of the new fitting and press it on with heat until it slides on? Clean the old solder with sandpaper and treat it as a new joint? As Clutch said above, I've learned this from doing and don't have much in the way of technique to fall back on.

I always used a propane torch, not so hot a tip....cut the flow down, grab with pliars, heat just enough, and twist off....

you need plumbing acid with a brush....and of course plumbing solder...I have used electronic solder in a pinch, same thing without the acid....

make sure the old and new fitting/solder areas are clean and shiney...you have any old corrosion or dark areas, they must be cleaned even if you file it....

put the acid flux on the pipe, shove new fitting on end, heat quickly and let new solder flow over top or around the joint 360* worth....it's a sense of timing, and you see the copper start getting dark, you got about 5 nanoseconds to get that flame off that thing or you back to cleaning and retry yet again.....

the copper simply has to stay copper colored, not MUD colored....

:bestwishes::clobbered:

Heat the existing fitting until solder will melt on it, not in the flame, but ont the fitting. Then using pliers pull the fitting off the pipe.

With a clean rag in hand, heat the pipe where the solder is on it and then wipe it clean with the cloth. A silver colored film of solder will remain, that is ok.

Take your new fitting, brush the id to clean it, then apply Oatey 5 or similiar soldering flux to the id of the fitting and to the pipe.
Slide together.
Heat the fitting only where it contacts the pipe.
Try to heat it evenly around its od.
Wipe the solder across the joint line every few seconds, ( but not in the direct flame), when the solder melts the fitting is ready.
wipe the solder around the joint starting at the top and down both sides.
A small drip of solder will form at the bottom.
Pull the heat as soon as the solder melts to the fitting and pipe.

Let cool until solder looses its shine, then wipe it off with the cloth you previously used.

If you carefully watch the flame color it will be blue, when the copper is hot the flame will get a green hue to it, that is as hot as you want to be, the copper is starting to burn.

Just a reminder since I haven't actually heard anyone mention it, but you know to scuff both mating surfaces with something like 100 grit tape or paper, right? I was on a job one time and lost my roll of sanding tape. I tried to get away with one of those 3M green scotchbrite pads. Just not enough. The red pad, maybe. But every joint I did with the green pad leaked. Luckily it was only a handful of joints and it was just leaking air, but I still had to pull off the job, get sand paper and redo all those joints for no charge.

Clutchdust said:

Just a reminder since I haven't actually heard anyone mention it, but you know to scuff both mating surfaces with something like 100 grit tape or paper, right?
.

Click to expand...

That I did know but it certainly doesn't hurt to repeat the obvious. As I said, I learned by watching and you can't always catch every step.

Ozzy said:

With a clean rag in hand, heat the pipe where the solder is on it and then wipe it clean with the cloth. A silver colored film of solder will remain, that is ok.


.

Click to expand...

This was the step that I was looking for. Common sense really, but I didn't think of doing it this way. On my previous attempts to replace a fitting, I always sanded off the old solder to get enough clearance to put the new fitting back on. Hard to do this evenly and predicatably. Didn't always work the first time.

Thanks again for your help guys. I ended up using Permatex thread sealer because I had some. Worked like a charm. I'll pick up some proper stuff for potable water use, but for now at least it is sealed.

Your problem with the threads leaking is pretty common these days. Years ago the most popular brand of copper fitting was Nibco, they were high quality with perfect threads. These days, common are much less quality no name with threads that look like they have already been severely galled and are more difficult to torque properly to seal.
The teflon tape isn't what it used to be either, about half as thick and who know about the composition.
The tape or sealant is primarily a lubricant for assembly and to fill any tiny voids where the threads don't seat properly.
It good practice to pick thru the adapters these days for the best ones.

010752 said:

Your problem with the threads leaking is pretty common these days. Years ago the most popular brand of copper fitting was Nibco, they were high quality with perfect threads. These days, common are much less quality no name with threads that look like they have already been severely galled and are more difficult to torque properly to seal.
The teflon tape isn't what it used to be either, about half as thick and who know about the composition.
The tape or sealant is primarily a lubricant for assembly and to fill any tiny voids where the threads don't seat properly.
It good practice to pick thru the adapters these days for the best ones.

Click to expand...

:shocking:

You have noticed the same shit also...eh?

:search:prrtt::gurney:

We still use NIBCO fittings.
The last 6 months or so I have noticed that their
2" male adapters are not making up tight until 1 thread showing. If the device is oversize at all you get thread lock and a leak, grrrr.

Smaller sizes still are making up correctly.

Other than the 2" problem mentioned, we have had no problems with thread leaks male or female with NIBCO adapters.

I prefer and sanding screen over sanding cloth.

Give me a nice half worn piece of screen
Cut the handles off the fitting brushes and chuck them in a cordless.
A can of Oatey 5.
A roll of Silverbrite.
and I'll be happy all day.

010752 said:

Your problem with the threads leaking is pretty common these days. Years ago the most popular brand of copper fitting was Nibco, they were high quality with perfect threads. These days, common are much less quality no name with threads that look like they have already been severely galled and are more difficult to torque properly to seal.
The teflon tape isn't what it used to be either, about half as thick and who know about the composition.
The tape or sealant is primarily a lubricant for assembly and to fill any tiny voids where the threads don't seat properly.
It good practice to pick thru the adapters these days for the best ones.

Click to expand...

This is so true. The big drop in quality came with the flood of imports from China. The quality was low but so many people bought on price, they didn't care. Then the quality companies had to drop their quality too just to be competitive. The problem for the end user is that nobody finished the threads anymore. Used to be you go buy a quality threaded fitting and the threads were smooth and perfect because the manufacturer would use good dies and finish the threads when done. Now they're just rough cuts with no finishing. You rub your finger across threads of any of these new fittings and you'll come back bloody. For a single application I would suggest you hit the threads with a thread chaser or even a machinists file before you sweat it on. It will give you better results.
20 years ago who would have believed the quality parts would be coming from Korea?

All you all got NOOOO fucking clue how many times a week I utter the words....

'everything we BUY is crap anymore'.....wife understands from looking over my shoulder, and knows I correct, took her a while, but over the ten years we been married, she remembers shit she learned while being the oldest of two daughters, and learning stuff around the house from her father....

then hearing my bitching over the junking of America.....at least she is tolerant of my 'tude'..... getting to be a hair trigger anymore....

:surrender::twitch::bestwishes: