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bbillcee
12-10-2008, 03:22 PM
i have an old 2" gal nipple that used to go to a 2 in trap under the sink.

should i use a no hub with sleeve to transfer to PVC then do all new trap etc in PVC

or use 2" inch to 1 1/2 reducer then use all 1 1/2 brass traps etc

which is most pro job? thanx

Verdeboy
12-11-2008, 10:35 AM
I don't know the most "pro" answer, but since no pro has responded, I'll take a shot.

Whenever I come across a galvanized stub-out, I like to screw on a FIP (female pipe threads) PVC adapter using teflon tape. In your case, you'll need the adapter to reduce from 2 in to 1.5 in. Next, I cement on a standard trap adapter to the spigot (SP) end of the adapter and now you are ready to install your 1.5 in PVC trap.

This is what a trap adapter looks like:

Redwood
12-11-2008, 01:03 PM
I do not advocate the use of any female plastic thread to connect to a metal male thread ever. It is almost a guaranteed leak even on a drain.

What is the condition of the thread?
If it is good you and put on a reducing coupling, then a 1 1/2" nipple then a slip joint washer and nut and put the tubular p-trap right into it.

bbillcee
12-11-2008, 04:25 PM
I do not advocate the use of any female plastic thread to connect to a metal male thread ever. It is almost a guaranteed leak even on a drain.

What is the condition of the thread?
If it is good you and put on a reducing coupling, then a 1 1/2" nipple then a slip joint washer and nut and put the tubular p-trap right into it.

well the nipple was screwed i was able to get it out and replaced with new nipple then i put the existing heavy duty brass trap back on that reduces to 1 1/2.....still planing the rest out i will definately be using brass

Redwood
12-11-2008, 04:58 PM
Sounds like you have it under control.

Verdeboy
12-11-2008, 09:57 PM
I do not advocate the use of any female plastic thread to connect to a metal male thread ever. It is almost a guaranteed leak even on a drain.

What is the condition of the thread?
If it is good you and put on a reducing coupling, then a 1 1/2" nipple then a slip joint washer and nut and put the tubular p-trap right into it.

I have never had a leaking problem when I screw on a nice deep-threaded FIP PVC adapter using teflon tape. I have seen leaks, however, when people try to screw either a metal or a plastic slip-joint nut directly to the galvanized pipe. The metal nut will eventually rust away, and that rubber seal is guaranteed to disintegrate over time and leak.

Redwood
12-12-2008, 04:37 AM
I have never had a leaking problem when I screw on a nice deep-threaded FIP PVC adapter using teflon tape. I have seen leaks, however, when people try to screw either a metal or a plastic slip-joint nut directly to the galvanized pipe. The metal nut will eventually rust away, and that rubber seal is guaranteed to disintegrate over time and leak.

A metal female with a plastic male into it is okay but not vice versa. I prefer to avoid any plastic to metal threaded connection myself.

As for the metal nuts rusting, that only happens when you use zinc plated steel nuts. I avoid those and use brass slip joint nuts.

Verdeboy
12-12-2008, 06:58 PM
What about when you need to transition from galvanized to PVC? Most P-traps today are PVC, and for good reason.

Isn't the seal used with the brass slip-joint nuts the same black rubber thing that always deforms, deteriorates, and eventually, leaks?

Redwood
12-12-2008, 08:59 PM
If I am transitioning from Galv. to Schedule 40 PVC I would use a Fernco Proflex Coupling. To Tubular brass or, poly the slip joint nut and washer.

http://www.azpartsmaster.com/images/catalog/ishop/6060.jpg

hj
12-13-2008, 07:01 AM
We use whichever connection is best for the particular installation. You have not told us anything about the actual pipe, other than its size and that is probably a 1 1/2" pipe, rather than 2". But a No-Hub type coupling would be the very last option when all else failed.