Shortening pipe nipples in bathroom before water shutoff valves

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Old 10-31-13, 03:53 PM
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Shortening pipe nipples in bathroom before water shutoff valves

Hi,
I have a bathroom renovation project going. I just found out that the vanities I've purchased (IKEA) require me to shorten the pipe nipples coming out of the wall. I bought some shorter ones, and I thought I could just unscrew the old ones, and screw in the new ones after adding some teflon tape to the threads. The pipes are, I believe, galvanized steel, and it seems like there are some horror stories around here. So I decided I would ask first if this is the best course of action, or if I should be trying something else, like cutting the nipples shorter and then using a compression fitting on the shortened pipe?

I have included a picture of one of the nipples and the current shut off valve if it helps.

Attachment 20326

Thanks for any advice.

Steve
 
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Old 10-31-13, 04:06 PM
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Welcome to the forums! Curious, why do you have to shorten the pipes, just because it is Ikea? What harm would come if you left them the same length?
 
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Old 10-31-13, 04:51 PM
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Thanks Chandler, it seems that these IKEA vanities are notorious because they have a sliding drawer that covers the entire width of the vanity, and they will not close if the shutoff valves extend much more than 3" from the wall. I similarly need to make sure the outgoing piping is close to the wall
 
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Old 10-31-13, 05:13 PM
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The only reason I was asking is because with cast iron pipes, it is best to leave them alone. BUT since you have to shorten them, you may be able to unscrew them and replace them with shorter nipples. You won't know the size until you remove it. Don't use Teflon tape. Use a good Rectorseal type plumbers sealant on the threads of both ends of the nipple and replace your stop valve as well.
 
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Old 10-31-13, 05:15 PM
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Yes, just unscrew the old nipple and install the new, shorter one. Que the horror music... I hate NPT fittings especially I can't see to confirm that they are not leaking. I would say tighten the snot out of it but in the wall where you can't grip the female fitting you have to walk a careful line between tight enough to seal and breaking something loose in the wall. Good luck.
 
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Old 10-31-13, 05:42 PM
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I should say that I think they are steel and not cast iron. Does that change anything? Assuming not, I'm going to try and replace them by unscrewing them and praying, probably tomorrow or Monday, so I'll have lots of time before the family gets home with the water shut off it needed.

I actually have four to do, so I'm a little nervous (there are two sinks).

Should I get lubricant to spray into the current threading? WD40 or something?
Would this increase the chance they screw off without breaking (which is one of the horror stories I've ready about).

Thanks for your advice, I really appreciate it.
 
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Old 10-31-13, 05:45 PM
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I spoke incorrectly. It is IPF, or an Iron Pipe Fitting, not cast. My mistake. Go gently and break them slowly. If you can shine a pen light into the hole after you reinstall the stop valves, you will have a warm and fuzzy moment should it not be leaking.
 
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Old 10-31-13, 06:09 PM
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I've just shortened the drawer instead of have to deal with a broken off steel fitting inside the wall.
Customers do not to hear the fact that at some point all steel fitting are going to rust to the point of leaking and are so closed up on the inside there already getting less flow from the corrosion.
 
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Old 10-31-13, 06:15 PM
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Are you saying you have the same type of vanity and have done this, or just proposing I do it? The house is 20 years old, so I suppose that is enough time for corrosion, but surely they didn't put pipes in a house that would corrode to the point of needing to be replaced in 20 years?
 
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Old 10-31-13, 06:19 PM
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Also, the house came with a water softener. I can't say how long it was in operation, or if the salt was properly kept at level, but presumably that should mean the PH was close to neutral, which should help (I hope).
 
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Old 10-31-13, 11:53 PM
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The house is 20 years old...
That's a pretty new house for having galvanized steel piping, I wonder why and why it was even allowed.

Also, the house came with a water softener. I can't say how long it was in operation, or if the salt was properly kept at level, but presumably that should mean the PH was close to neutral, which should help (I hope).
A water softener has little, if any, effect upon pH. Truth is, soft water is more corrosive than hard. Where I live most of the municipal water supplies are from mountain snow melt and naturally soft. The water utilities have been ADDING calcium (hardness) to reduce pipe corrosion for at least the last twenty years.

Don't bother with any kind of solvent or penetrating oil, it won't work. I personally would not use anything larger than a 10 inch pipe wrench because if that doesn't loosen them most likely they won't come loose without having to use a back-up wrench on the tee or elbow in the wall. Definitely use the Rectorseal #5 thread goop instead of Teflon tape. You could use Teflon goo instead of the Rectorseal but I personally would go with the Rectorseal. Use the 10 inch wrench to tighten and take them at least as tight as the old nipples, maybe a quarter-turn more if you can but no more than that.
 
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Old 11-01-13, 03:03 AM
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20 years old, my bet is the galvanized iron is just a "firmness" thing so it all doesn't move. Hopefully it threads into a brass elbow and is either copper or other material below. Have you determined there is iron pipe throughout the house? Not just at the poke throughs in the wall?
 
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Old 11-01-13, 05:40 AM
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With that age a house, the piping is probably copper with brass elbows, with just the nipple being galvanized steel. In my opinion, you probably won't have any issue unscrewing and replacing the nipple. I've done it before with no issues.

BUT... as you said, it's hard to tell until you actually do it. Try to do it earlier in the day, just in case you do run into a problem the stores will be open.
 
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Old 11-01-13, 07:41 PM
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With that age a house, the piping is probably copper with brass elbows, with just the nipple being galvanized steel.
Why would anyone use copper piping with brass (drop ear) elbows and then steel nipples? If they wanted to have threaded nipples they would have used brass or bronze nipples.

Unless they were stupid.
 
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Old 11-02-13, 03:41 AM
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I guess it is similar to the theory of the tub outlet. Some pipe down with copper, turn with a brass elbow and use galvanized for the spout itself. Doesn't make sense to us, but maybe they were using the same idea, who knows.
 
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Old 11-02-13, 06:15 PM
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Yes, I went to a part of the basement last night where there is still some piping exposed, and you're correct. It is copper.
 
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Old 11-09-13, 09:34 AM
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Thanks

Thanks everyone for the help. I replaced all of the nipples over the week, and there does not seem to be any leaks. I really appreciate all of the advice.
 
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Old 11-09-13, 10:25 AM
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Glad you got it done without incident. Thanks for the report.
 
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