Plumbing question

[Sukhoi]

I need to modify the plumbing on the drain of a sink. Working backwards, the PVC pipe comes out of the wall. It has a socket-weld to threaded (NPT I hope!) adapter. The PVC P-trap screws onto this adapter, and then into the bottom of the sink.

Are the threads on that adapter NPT? Are there any other threads commonly used in that situation?

 

[Sukhoi]

Bump for plumbers.

 

[rhino56]

whats npt?

 

[Sukhoi]

National Pipe Taper thread. It's the standard thread for threaded pipe fittings. I'm just not sure if that PVC thread is likely NPT or not.

 

[drnickriviera]

It should be standard pipe thread

 

[Ornery]

1. I'm pretty certain it's inch and a half, or inch and a quarter NPT.

 

[Sphexi]

Bathroom sinks generally use inch and a quarter, kitchen sinks use inch and a half, almost all I've seen are NPT.

 

[Ornery]

1. What do they use in Canada?

 

[tyler811]

Originally posted by: Sphexi
Bathroom sinks generally use inch and a quarter, kitchen sinks use inch and a half, almost all I've seen are NPT.

:thumbsup:

 

[Sukhoi]

Thanks guys! Now I can order all my junk this weekend. I've measured the thread with both a ruler and calipers and both came out to 1 3/4" diameter, so it's a 1 1/2" pipe. It's just amazing how much large threaded wyes are. :Q $26.87 for galvanized iron. I know that isn't great stuff for a drain, but brass is $63.88!

 

[Ornery]

1. Why not adapt or convert to PVC?

 

[Sphexi]

Originally posted by: Sukhoi
Thanks guys! Now I can order all my junk this weekend. I've measured the thread with both a ruler and calipers and both came out to 1 3/4" diameter, so it's a 1 1/2" pipe. It's just amazing how much large threaded wyes are. :Q $26.87 for galvanized iron. I know that isn't great stuff for a drain, but brass is $63.88!

Yep, it can get pretty expensive, but it'll last for years and years without a problem. Also looks a heck of a lot nicer than PVC, even though it's under a sink.

 

[Ornery]

1. Pssst, he's buying galvanized pipe, not chrome.

 

[NascarFool]

Galvanized pipe is the worst thing to use for sewer or water. You are better off going to ABS fittings and pipe or PVC.

 

[Fritzo]

Originally posted by: Ornery

1. Why not adapt or convert to PVC?

I did this on my sinks in my old house. Well worth it.

 

[Sukhoi]

See the problem is that McMaster doesn't sell threaded PVC wyes. I have to order from McMaster too. I can either use a galvanized wye or a threaded PVC tee. I'm worried if I use a tee that if the water comes into the tee from the perpendicular direction too quickly it is going to backup into the sink. A wye would eliminate a lot of the backup possibility since the downstream pipe would actually have to get completely full for it to backup.

Additionally I don't really have room to use an unthreaded PVC wye and then use threaded adapters on all sides of it. The inserted piece needs to be as short as possible. Luckily the sink is not used much at all so I really don't think galvanized is going to corrode too quickly.

 

[dartworth]

That galvanized pipe will last longer than you need to be concerned with...

 

[DrPizza]

Why are you limited to McMaster??

I find those prices to be amazingly high.

 

[Sukhoi]

Originally posted by: DrPizza
Why are you limited to McMaster??

I find those prices to be amazingly high.

Luckily it's not my money. It's for a school research lab so all purchasing has to go through the department office for that, and it's a PITA to have to do multiple orders for stuff. We're on time constraints here too. I also need a billion different things from elbows, pipe sections, ball valves, check valves, hose with threaded swiveling connectors of various lengths, and a pump. Much easier to just order it all from McMaster.