DIY Home Improvement Forum banner
1 - 13 of 13 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
I'm installing a new vanity and sink and had to move over the hot water supply to allow for the drawer of the new vanity. (Pipes are original, 1963 house) The original plumbing had a 3/8" female threaded galvanized connection for me to screw into, so I used some elbows and pipe nipples to move over where it would enter the back of the vanity. First, I used teflon tape on all of the connections and when I turned on the water everything was fine except a very slow leak (1 drip every 10 seconds or so) where the new pipe screwed into the old threaded fitting. So, I took it all apart, wiped it down, and tried pipe dope (Rectorseal 5) and the exact thing happened, except that as I got to the end of the tightening I saw a small shard coming out of the threads. I turned on the water and same thing, very slow drip.

I had read about some people using both teflon tape and pipe dope and had read others discouraging it. I figured I'd give it a try and see what happened. So, I took it back apart, wrapped in teflon tape, and then applied the pipe dope. As I screwed in, as it got really tight (14" pipe wrench, grown man pushing pretty darn hard) a few more shards of metal came out. I know it wasn't cross threaded, so I assume I was getting into metal that hadn't been threaded yet. (?)

But, no leak!

So, my question is this: If it's holding now, am I good to go? Can I trust it to hold? I don't want to install the vanity and have it leak sometime down the road.

Thanks in advance for your help.

-Collin
 

·
Registered
Joined
·
1,525 Posts
Sounds to me like you'll be fine. I use tape + dope all the time when I join steel pipe. One question I have is did you clean the 3/8" female connection prior to tying in the new pipe?

P.S. - Galvanized pipe is notorious for filling up with sludge and becoming brittle, esp. after almost 50 years in service, so you might want to start planning to replace it. Soon.

 

·
Registered
Joined
·
3 Posts
Discussion Starter · #3 · (Edited)
Thanks VIPlumber for your reply.

The pipe nipple that exited the female connection was full of sludge, but the connection itself was quite clean. I cleaned out what I could with my hand. It's all copper until that connection and it looked pretty clean to me.

So I don't need to be worried about where the shards came out as I reached the end of the threads?

Thanks.
 

·
Premium Member
Joined
·
11,951 Posts
I tape and dope all galv. threads. Doesn't make any difference, but I put the dope on first :laughing:
If you used a 14" wrench on 3/8 you probably got it a little too tight. But if the fitting didn't split or drip you're good to go. BTW, rectorseal 5 is good stuff
 

·
Hvac Pro
Joined
·
23,688 Posts
Yep. I use both and have done high pressure water with 2" galvanized in a hospital that way. Galvanized always seems to need both.
 

·
Plumb or Die!
Joined
·
321 Posts
I tape and dope all galv. threads. Doesn't make any difference, but I put the dope on first :laughing:
If you used a 14" wrench on 3/8 you probably got it a little too tight. But if the fitting didn't split or drip you're good to go. BTW, rectorseal 5 is good stuff
I put the tape on first, then the dope. This is a common debate between all plumbers, gasfitters, steam fitters and sprinklerfitters. :thumbup:
 

·
Hvac Pro
Joined
·
23,688 Posts
Too messy the other way. I like to get the metal threads to bite into the tape (pull on the tape to get it seated) and add the dope. Always use the thicker pink Pro teflon tape. The white stuff is too light duty and for wusses.:laughing:
 

·
Premium Member
Joined
·
11,951 Posts
Too messy the other way. I like to get the metal threads to bite into the tape (pull on the tape to get it seated) and add the dope. Always use the thicker pink Pro teflon tape. The white stuff is too light duty and for wusses.:laughing:
Blue Monster tape for me. And it goes on top the dope! :jester:
 

·
Hvac Pro
Joined
·
23,688 Posts
Plumbers are messy, I have 5 of them at work. One leg covered in white silicone, the other in pipe dope.:laughing:

Furnace installers, One leg covered in PVC glue, the other with silicone.:)
 

·
Registered
Joined
·
1,117 Posts
Dope, tape and dope only on the male threads. Works really well for me. Putting dope on female threads forces dope into the water pipe when the pipe is screwed in.

HRG
 
1 - 13 of 13 Posts
Top