leak free threaded pipe joints

[Eigenvector]

This is really more of an exasperated shout out than a question but sometimes you just have to ask.

After having performed many small repairs to my galvanized pipes, I'm repeatedly thwarted by the threaded connections between the galvanized and the replacement. Is there a real good trick to making a leak proof connection between an old pipe and a new one? I've tried using teflon tape in small amounts on the threads, I've tried reefing down on the joint so hard the planet tilts sideways in reaction, I've tried cleaning the two joints so well that you could see my reflection in the threads from a block away. None of this ever produces a joint that stays leak free. I don't mean a gusher, I mean drip.........drip............drip...............drip. It does stop dripping, after about 2 weeks when rust forms between the two pipes.

Everyone talks about pipe dope, I have yet to try that, mostly because after a while my stubborness overcomes reality and after that all rational thought is blocked. I guess I just don't see what pipe dope would do that 2 tons of torque on the joint wouldn't. Just kidding really, I do understand that too much force distorts the threads and probably makes the leak worse.

I don't seem to have this problem betwen two new pipes, only between the old galvanized and the new one.

[Speedy Jim]

Common problem with old galvanized pipe; the threads deteriorate so badly that they can't possibly seal.

Pick up a small bottle of Loc-Tite thread sealant. It makes a permanent seal without any tape or dope. Apply to bright, clean threads.

Jim

[Edwin Pawlowski]

Millions of plumbers are wrong.

[hallerb]

use tape AND dope. This assures a leak free joint:)

Bigger question why not end the hassle and upgrade to PEX or copper?

Sure initially its a bit more work, but it was outlast your lifetime!

contiuning repairs to galavinized is just a grand waste of time and effort

[BobK207]

Thirty years ago I was a big fan of teflon tape. I was jammed up for time on some plumbing so I hired a pro.

He told me to "stop using that crap (teflon tape) & switch to a good dope"

He used RectorSeal & so have I even since.

Tons of torque is not the anawer! It won't overcome the imperfections in the typical threaded galv pipe & fittings.

If you insist on staying with teflon tape use at least 3 complete wraps maybe even 4 or 5. It will mush out of the way.

cheers Bob

[digitalmaster]

pipe dope lubricates the threads as well as seals so when you torque down on the pipe it gets way tighter with dope than without.

Plumbers, Pipefitters, and Service Technicians local 72 card number 1465687

[arthur.moore]

The plumber I use uses teflon tape and then pipe dope over the teflon tape. The pipe dope he uses was white. He is the only plumber I have used that does it this way. He is also a plumbing inspector. I am assuming he does this to elimniate any problems.

[Bennett Price]

Perhaps that's the problem; put three or four turns on.

Eigenvector wrote:

[Eigenvector]

Thanks all for the replies.

Sometimes the solution is "over here" and stubborn me is looking at options he knows how to use - trying to get that darn square peg into the round hole. The trick is to overcome my stubborness. Someone mentioned that "millions of plumbers are wrong" sarcastically, well to that I say, I'm not a plumber, have never owned a house and don't have a clue what they use to fix pipes reliably. I'm not born with an innate sense of what works, so I hear about product x,y, and z try them and see what works. Its only after trying a few options and dope was the last one on my list - I started to hunker down disbelieving that NONE of those options work reliably. As someone else mentioned, the threads are undoubtedly beginning to deteriorate on the old pipe ends.

Someone else asked why I was repairing the pipes at all. I'm not, I'm actually replacing sections of the pipes with PEX until I can afford the downtime required to do the whole system properly. I can't rip out my bathroom tiling, redo my kitchen cabinet work, or all the other myriad things that would come from replacing with PEX - so I do it in small steps and take care of the worst offenders - I'm also teaching myself how to use it so that if it becomes a REAL problem I'm not totally clueless.

Again I appreciate the replies, sometimes having an entire group shout "USE IT!" does help.

[Colbyt]

Now that you have tried it the hard way and easy way many times, may I suggest you try it the right way.

Buy a bottle of the better pipe dope. Coat the threads. Tighten the pipe and enjoy life.

Colbyt

[hallerb]

I certinally hope your not connecting say copper to galavanized directly. Dissimiliar metals cause corrosion and fast failure.

All such dissimiliar meatls MUST use a isolation coupling

[Mr.E]

Switch to Rectorseal #5. I did years ago and will not waste my time using any other dope.

[Bob]

I have been told that a brass fitting between galv. and copper will do the job also. True?

Bob

[Eigenvector]

That's why I'm doing the repair work - the previous owner did in fact do that. The joint has since blown out under pressure.

[Eigenvector]

Brass on steel will corrode as well. In fact it's pretty tough to join two dissimilar metals together without corrosion - although some combinations corrode much faster than others. I know this through my engineering training, not practical experience so take it for what you will.

[Don Young]

It may help to know that standard taper pipe threads are in fact not intended to seal by themselves. The design allows for a small clearance between the tops of the threads and the bottoms of the mating thread grooves. This creates a small spiral leakage path around and along the threads which must be closed by some type of sealer. For more information, check up on "dryseal threads", which do seal themselves.

Don Young

[John Gilmer]

Amen!

I don't recall the brand name but I like to use "teflon filled" pipe dope. The nice thing about the teflon is that it lubricates the pipe and make it easily to tighten but dope definitely seals better than tape.

[BobK207]

The dope I suggested RectorSeal is teflon filled

RectorSeal=AE T PLUS 2

cheers Bob

[Goedjn]

Aren't american standard pipe-threads truncated, so that the peaks don't completely fill the troughs?

[Don Young]

They sure are. Only "dryseal" threads are designed for sealing. Don Young