Removing brass p-trap from galvanized steel pipe

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Old 02-15-16, 10:40 AM
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Removing brass p-trap from galvanized steel pipe

I am replacing a sink with a larger one and need to replace the existing brass trap with PVC so I can adjust where the drain is lined up.

I'm not sure how to remove it though. The entire trap appears to be threaded on to a short galvanized nipple with that same nipple threaded in the galvanized waste pipe into the wall. Most of the threads are covered by a loose metal collar that can slide back and forth.

My first thought is to get a cheater bar stuck down the trap or a wrench and twist it off but that could also loosen the threads of the nipple into the waste pipe. The nipple appears to be in good condition from what I can see (no apparent damage where the two metals meet).

Can anyone tell me the proper way to remove this and replace with pvc? Or is there another method I should use? Can I remove the entire nipple and replace with a piece of threaded PVC (The waste pipe is flush with the wall)?

I have included some pics below:

Need to replace


Nipple threads on p-trap side


Nipple threads on wall side (note the metal collar slides back and forth):


Thanks!
 
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Old 02-15-16, 11:43 AM
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Just unscrew it. Doubtful the nipple will unscrew, but if it does, just screw a slightly longer nipple back in after you've removed the trap. Using a long nipple will give you room for a wrench. Then you can screw in a Trap adaptor with male threads.
 
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Old 02-15-16, 11:49 AM
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I too would just unscrew it. Something will give either the trap or the nipple. Either way it doesn't really matter since you can just put a new nipple in if you need to. You may just be able to use a threaded PVC adapter and screw that on and not need a nipple.
 
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Old 02-15-16, 11:50 AM
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I wouldn't try to remove the nipple from the tee in wall.
I would cut the trap off using a reciprocating saw and connect the new trap using a shielded no-hub coupler.
The 1-1/2" no-hub will connect the cut off pipe to an adapter, which can be ABS, PVC, or a trap adapter for using slip tube PVC fittings.

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Edit: Agree with Dane if you can get the nipple out. Use penetrating oil, not WD 40.
 
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Old 02-15-16, 12:06 PM
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Thanks guys. I will try some PB Blaster and see if I can unscrew it.

Short of that I can cut it and use the no hub fitting. However, Handyone, the part you indicated to cut is threaded (the sleeve is blocking the view. Will the no hub fitting work with one end on threads?

The other question, do they make a female pvc adapter that will thread onto this nipple or a male pvc adapter that will thread into the cast iron hub if I do get the entire nipple out from the wall?

Thanks again!
 
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Old 02-15-16, 12:27 PM
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Ok I got the p-trap off without much trouble. It looks like the nipple is corroded where it met the brass.


So is the no hub my best option? It seems like I should get rid of the nipple as it can catch stuff and cause a blockage. How do I remove that? Should i?



 
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Old 02-15-16, 12:54 PM
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You could cut off the threaded part and use a no-hub like Brian suggested. Personally, I'd remove the nipple and either screw in a new one or see if a trap adaptor screwed right into the tee would be long enough, like PD suggested.
 
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Old 02-15-16, 02:09 PM
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The threads need to be cut off to use a no-hub. BUT, the nipple should be replaced as said by others.

It might break off trying to remove it. I would check a local plumbing store and see if they will let you borrow an 1-1/2" tap. Whether the pipe breaks off or not, the tap will let you clean the tee threads thoroughly after nipple is removed.

The other question, do they make a female pvc adapter that will thread onto this nipple or a male pvc adapter that will thread into the cast iron hub if I do get the entire nipple out from the wall?
Either fitting is available.
 
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Old 02-15-16, 03:06 PM
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Well I tried with channel lock pliers and it won't budge. Any tricks to getting it off?

And if I do get it off and put a new nipple, should I cut that one to use a no hub or use the pvc threaded connector?

If I do cut it I'm thinking there is no way I can get it perfectly strait with a sawsall. I'm thinking I could do better with an angle grinder with a metal cut off wheel but it may not be perfect. Will that impede the no hub seal?

In doing some research it seems that the other part of the threads connected to the waste pipe are usually ok because it's steel on steel.
 
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Old 02-15-16, 03:18 PM
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You need a big wrench to get that out.. an 18" maybe?

Once out install a pvc male adapter/Then a piece of pvc pipe and a trap adapter...
 
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Old 02-15-16, 03:49 PM
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I didn't try my pipe wrench yet as I wasn't sure I could get a good grip on it.


That said, am I opening up a can of worms trying to remove the nipple? I'm sure I cannot rent a thread cutter so it would be costly.

If I cut past the threads would the no hub be the better option?
 
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Old 02-15-16, 03:59 PM
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Cutting off the threads and using a no hub coupling would be the safest option...
 
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Old 02-15-16, 04:09 PM
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Considering my luck, I may have to go that route. I can at least cut the threads off with my angle grinder and if the pipe is too corroded I'm really no worse off
 
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Old 02-15-16, 04:17 PM
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Just use a no hub connector. Sometimes you can overthink these things. I'd probably cut off the nipple so only enough remained for one side of the no hub just to be sure I had room for the trap. You can get a male trap adapter to fit in the no hub.

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Old 02-15-16, 05:09 PM
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Yes as rays shows.. But you want to leave enough steel pipe to the trap will fit in... If you cut too short the trap may not be long enough to reach the center of the sink... Hence why the suggestion to PVC
 
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Old 02-15-16, 05:39 PM
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You bring up some good points. The original installer in the 50's brought the pipe out of the wall so it is angled to the left as you are facing it (awesome, thanks).

Since the new sink is bigger the drain will be to the right. To me this means I'll have to use a pvc angled fitting or somehow get the trap pointed a few inches in the other direction.

That said, probably the shorter the steel pipe the better?
 
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Old 02-15-16, 06:04 PM
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Try the full length pipe first and cut only if needed.
 
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Old 02-15-16, 06:17 PM
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Oh, good grief!

Remove the steel nipple. It may take as big as a 24 inch wrench. If you still can't get it out then cut it as close to the wall as possible and then use a cold chisel and a big hammer to collapse it and then remove it from the sanitary tee.

Buy a brass trap adapter, slather the threads with Rectorseal or Teflon paste and screw it into the sanitary tee tightly. Then use PVC drain tubing and trap. Done.

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Old 02-15-16, 07:12 PM
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Ray - my interest in cutting the threads is the metal is corroded and has sharp edges which will trap hair and likely clog.

Furd - I want to stay away from two dissimilar metals as that is what caused the corrosion.
 
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Old 02-15-16, 07:46 PM
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Buy a brass trap adapter, slather the threads with Rectorseal or Teflon paste and screw it into the sanitary tee tightly. Then use PVC drain tubing and trap. Done.
But it may be too close to the tee in the wall for the trap arm to fit.. Or you may need a really long trap arm with very little going into the adapter...


Furd - I want to stay away from two dissimilar metals as that is what caused the corrosion.
Brass is fine with steel..


Ray - my interest in cutting the threads is the metal is corroded and has sharp edges which will trap hair and likely clog.
And looking at the gunk in the pipe is another reason I would remove it and change to pvc... But thats me...
 
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Old 02-16-16, 11:30 AM
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I would remove the nipple. It may be a bugger to remove but horizontal runs of galvanized have a bad habit of developing leaks on the bottom so I like to get rid of them altogether. Vertical sections last a long time but it's the bottom of horizontal runs that cause me trouble. If you can't get it out I'd even consider cutting open the wall and use a reciprocating saw to cut the vertical pipe and use a no hub coupling to install a PVC elbow and pipe to come out of the wall.
 
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Old 02-16-16, 12:02 PM
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I'm gonna give this a shot over the weekend as I had some spackle and grout work to finish.

I found a video on YouTube that showed cutting the inside of the pipe with a sawsall. I doubt I could do that without cutting the threads though.

One thing he mentioned was that the brass to steel connection is what corrodes due to the dissimilar metals. Yet the steel to steel on the other end of the nipple is usually fine.

I didn't try the wrench yet as I wasn't sure I could get a good grip with the nipple having a smooth surface. I saw another vid that said tighting it a bit first might be enough to break it loose.

I'll report back when I give it a try. My fear is making it so much worse than it is now.

I'm also open to tips on cutting it strait if I go that route. An angle grinder or rotozip with a metal cutoff wheel seems to be my best option. No way I could get it strait with a sawsall.
 
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Old 02-16-16, 01:26 PM
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I found a video on YouTube that showed cutting the inside of the pipe with a sawsall. I doubt I could do that without cutting the threads though.
Forget about that video..I saw it...


http://www.pdhcenter.com/courses/s118a/s118content.pdf

This is the wrench you need..

 
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Old 02-16-16, 02:26 PM
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Furd wrote:
Buy a brass trap adapter, slather the threads with Rectorseal or Teflon paste and screw it into the sanitary tee tightly. Then use PVC drain tubing and trap. Done.
Lawrosa wrote:
But it may be too close to the tee in the wall for the trap arm to fit.. Or you may need a really long trap arm with very little going into the adapter...
spta97 wrote:
Furd - I want to stay away from two dissimilar metals as that is what caused the corrosion.
Then buy the appropriately sized PVC or ABS male thread to female socket adapter as well as a male trap adapter and glue them together. Remove the nipple and replace it with the plastic parts, remembering to use the paste-type thread joint compound.

spta97 wrote:
I found a video on YouTube that showed cutting the inside of the pipe with a sawsall. I doubt I could do that without cutting the threads though.
You cut to just before the threads start, use a hand hacksaw blade if needed. Cut in two places and use a chisel and large hammer to knock out the small piece. Then use the hammer and chisel to collapse the nipple. I've taken out lots of nipples that way and never damaged the threads. A little nick on the threads won't hurt anything.
 
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Old 02-16-16, 03:58 PM
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Thanks again guys.

I went to the box store and picked up some parts. The no hub is if I can't get the nipple out. Otherwise I'm going to go with the pvc adapter.

The bagged all in one assemblies for the p-trap were cheap feeling so I would like to use 1 1/2" pvc (i think its schedule 40) for the entire piping except for the tail piece. The one in the pic is 1 1/2" but I'll get a 1 1/4". I also have a few elbows if needed to direct the pipe if necessary.

Couple questions:

1) Any issue with this setup?
2) Assuming I can use the PVC adapter, do I use Teflon tape or pipe dope? Both? Neither?

I much prefer to rely on solvent welds ad much as I can as I've had batter luck gluing than screwing .


 
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Old 02-16-16, 04:43 PM
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Assuming I can use the PVC adapter, do I use Teflon tape or pipe dope? Both? Neither?
I have much better success using a paste pipe joint compound. Make sure it states it is for PVC plastic fittings.
 
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Old 02-16-16, 05:36 PM
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The set up you show is good. You only need a short piece of PVC pipe to connect the adapter to the trap. Purchase a 12" piece and you can cut it to length.

For the adapter threads I would apply both tape and Teflon paste. You might only get a few turns on the adapter, which is good enough and the paste helps a lot.

The 1-1/4" tailpiece adapter I would make higher if possible, an adapter connected to the trap with a short section of pipe.
 
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Old 02-17-16, 11:21 AM
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Thanks guys. I got the rectoseal (sp?) which is good for pvc as well as the 1 1/2" to 1 1/4" converter which fits on the outside of the pipe so I can raise that up to the tailpiece.
 
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Old 02-17-16, 06:04 PM
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I got the nipple out! That sucker was in there tight. I used the regular ~12" wrench and my back is going to regret it.

I feel like I need a tetanus shot with all the gunk in there but the threads are shiney and seem to be in good shape.

I poked out some of the easy stuff with a screw driver for a few minutes and got this, I'm happy with it:



I'm amazed the previous sink drained.

Interestingly, it does not appear to be a tee. Rather it seems that another pipe is connected and goes strait down after an angle. I'll go in the crawl space to see if it's worth cutting out the whole thing for PVC but I feel I should just leave it alone.
 
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Old 02-22-16, 08:15 PM
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Another quick question. I screwed the pvc connector into the fitting after two wraps with Teflon tape and a liberal coating of pipe dope.

Using channel lock pliers, I was able to get it in really far. If I kept forcing it I probably could have bottomed it out but I didn't want to break it so I got it on there tight.

Is this typicall? I thought it would stop sooner. I probably have a few threads exposed.
 
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Old 02-22-16, 08:43 PM
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I thought it would stop sooner also, but it's not a bad thing it didn't.
No need to torque it down further. With the tape and the dope all that's needed is to snug it up and maybe less than a full turn.
It sounds like you're good, better than usual when replacing old fittings.
 
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Old 02-23-16, 06:42 PM
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Thanks Handyone! Hopefully smooth sailing from here.
 
 

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