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Galvanized to copper water pipe

pjmcgarvey | Posted in Construction Techniques on December 8, 2005 09:29am

There are alot of long-winded discussions in the archives, some of which mention brass nipples, and dielectric unions… so I’m still a bit confused.

I would like to convert to copper in the house after the shutoff.  The copper to galv soldering I’ve done so far is corroding, or at least I’m assuming it’s galv pipe, has a grayish outside, and the cross-section is silver – doesn’t look like copper.  Probably original to my 85 year old house.

The dielectric unions I’ve seen are threaded on both ends and have plastic, so how does one solder with a transition like this, since the plastic might melt?  Do I basically need to solder on 2 threaded female ends and connect together via the union?  Do they make galvanized female ends, haven’t seen them…

Previous posts indicate the brass has enough copper that it would still be a corrosion issue with the galv pipe? 

Thanks, PJ

 

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  1. User avater
    Homewright | Dec 09, 2005 12:47am | #1

    The copper to galv soldering I've done so far is corroding, or at least I'm assuming it's galv pipe, has a grayish outside, and the cross-section is silver - doesn't look like copper.

    How did you solder these?  That's not a normal method.  A dielectric union has two female threaded parts where you thread one side of the union half on the galvanized end while the other is threaded onto a male adaptor which then solders to your copper.  The plastic sleeve inside isolates the two sides keeping them separate thus keeping the corrosion from the dielectric process from being an issue.  Did you cut the threaded portion of the galvanized pipe off and are trying to make the joint up by soldering?  That's what it sounds like...  

    1. pjmcgarvey | Dec 09, 2005 03:31pm | #6

      So far people have recommended sweating at least one end (to the new copper) and threading the other end.  I can handle the sweating part.  How would one thread the other end into pipe which is not already threaded and is galvanized - basically supply pipe just cut off?  I don't want to get involved with threading my own pipe, sounds like a recipe for disaster since this is my house water supply, and old pipe....

      So do they make female adapters I can sweat to a galv pipe, to receive the threaded end of the union?  Didn't see em at the home centers - then again that aisle can be pretty intimidating...

      Since I have no idea how many different types of parts in plumbing supply land, can anyone point to specific examples of unions/adapters that will work here? 

      Thanks alot,

      PJ

       

      1. Danno | Dec 09, 2005 04:04pm | #7

        I don't think you can sweat anything to galvanized (don't think you can solder steel). There are rubber connectors (sleeves) that go over the galvanized and are held in place by steel pipe clamps. Maybe have to use one to fasten either a threaded nipple to the cut off galvanized pipe so that that can then be threaded onto the dielectic union. I've used those sleeves for waste pipes, but think they are also made for supplies.

        1. Hudson Valley Carpenter | Dec 09, 2005 04:32pm | #8

          66852.8 in reply to 66852.7 

          "There are rubber connectors (sleeves) that go over the galvanized and are held in place by steel pipe clamps. Maybe have to use one to fasten either a threaded nipple to the cut off galvanized pipe so that that can then be threaded onto the dielectic union. I've used those sleeves for waste pipes, but think they are also made for supplies."

          What Danno said.  Your choices are, (a) get the sleeve couplings or (b) remove the cut piece of galvanized pipe from it's threaded fitting and start there with a brass nipple, then add a copper female adapter, to which you can sweat your first piece of copper pipe.  Brass between galvanized and copper is a very effective means to halt corrosion.  Lots of homes in Southern California, where I'm currently living/working have transitions like I described.  Including the house I'm working on at present.

          This is the kind of question which is usually easily answered by a local person, someone at the plumbing supply house.  I've found one guy at Larry & Joe's who really knows his stuff.  He's saved me a lot of headaches and some big $$ on my current bathroom remodel. 

          1. User avater
            BillHartmann | Dec 09, 2005 04:55pm | #9

            I used a different type of repair fitting. It is steel tube with screw caps and rubber compression rings.In fact I used that as the dielect. Galvanized on one side and brass on the other. I used the brass as I was afraid that the pressure might collapse copper pipe. Then threaded the brass to a copper female fitting.

      2. WayneL5 | Dec 09, 2005 06:10pm | #11

        Galvanized pipe cannot be soldered.  For that end of the connection you need a threaded fitting.  You can either thread the existing pipe in place with a threading tool, or unscrew the length of pipe and replace it with a length threaded on both ends, or take the length to a plumbing supply house and have the open end threaded there.

        It is difficult to thread in place.  Doing so would not be my choice.

        Using brass as a transition between galvanized and copper is ineffective and unacceptable.  A dielectric union is the proper way to go.

        As a previous poster said, there is a real possibility the pipe you think is galvanized is lead.  Try sticking a magnet to the pipe.  If it is galvanized steel a magnet will stick.  If it is lead it will not.  If you have lead pipe you should have a plumber replace the whole thing.

  2. apiersma | Dec 09, 2005 12:56am | #2

    Sounds to me like you'll need to cut some new threads into the galvanized pipe and then add a dialetric union.

  3. Shacko | Dec 09, 2005 01:23am | #3

    Dielectic unions are made with a screw thread on one end and a sweat joint on the other, this is what you need. Hope this helps.

  4. MSA1 | Dec 09, 2005 01:55am | #4

    Dielectrics also come sweat on copper side thread on galvy side. Disassemble the union before sweating (but dont forget to put the pieces on the pipe first).

    You'll be fine.

  5. WayneL5 | Dec 09, 2005 06:45am | #5

    You must not connect copper or brass parts to galvanized.  Doing so will greatly accelerate corrosion.  People often do, but sooner or later the system fails.

    Brass and copper can be used in contact with each other.

    The dielectric union is the correct fitting to transition from one to the other.

  6. csnow | Dec 09, 2005 05:35pm | #10

    "I would like to convert to copper in the house after the shutoff.  The copper to galv soldering I've done so far is corroding, or at least I'm assuming it's galv pipe, has a grayish outside, and the cross-section is silver - doesn't look like copper.  Probably original to my 85 year old house."

    Is it lead?  Galvanized is generally threaded, and was not available 85 years ago.  Does it have a rust coating on the inside?

    If galvanized, solder is not a good choice- you would be better off cutting threads on it.

    1. JohnSprung | Dec 10, 2005 02:32am | #12

      > Galvanized is generally threaded, and was not available 85 years ago. 

      That's surprising.  Do you have a source for that?  When was the first galvanized pipe used in construction?

      As for dielectric unions, I've seen them fail.  At least for water heaters, the braided stainless has been far better.  Galv to stainless to brass or copper seems to hold up even better than those dielectric unions did.   

       

      -- J.S.

       

    2. pjmcgarvey | Jan 04, 2006 12:27am | #13

      Would like to revive this post for some add'l opinions...

      So my pipe appears to be lead, magnets don't stick to it, and seems to fit the description of lead piping I've found elsewhere.  I'm assuming there might also be some lead solder in places that I have not worked on. 

      In addition to the worries I now have about lead piping in my house, and the effect it might have on my 5 month old daughter...

      How do I go about transistioning from lead to copper?  Does lead and copper still need some sort of dielectric union?  I'm assuming I can just solder the new copper to the lead, b/c that's what I've done on many other parts of the supply pipe over the past few years (unknowingly), and though some corrosion is showing, it's held up fine to my amateurish soldering skills.

      I've contacted my local water authority to see what they say about possible replacement. 

      Thanks,

      PJ

      1. User avater
        Luka | Jan 04, 2006 12:50am | #14

        Get a PVC universal connector.It is like a pipe with rubber compression rings at both ends.Unscrew the end of it. Slide that ring over the pipe. Slide the rubber ring over the pipe behind it. Slide the union onto the pipe behind that. Now screw the end back on, capturing the rubber ring in between.Do that at both ends.Cheap. Fast. Easy. And permanent.
        Rudeness is the weak man's imitation of strength. ~~ Eric Hoffer

      2. csnow | Jan 04, 2006 04:16am | #15

        The reality is that very little lead leaches out of a cold lead pipe once it has been in service for a while.  It develops a coating on the inside.  To be extra cautious, you can avoid getting drinking water during "first draw", meaning after the water has sat in the pipe overnight or while you have been away for a while.  Run water long enough to purge the line.

        Lead pipes remain very common for home water supply lines.  My own child has a very very low lead level despite a lead supply line.  Replacing them can make you feel better, but the risk is really very low.  Even if you replace your own, there are still municipal lead supply lines in many localities.

        The local Conservation Law Foundation is all up in arms about lead supply lines at the home level, so there is another view on the matter.  Of course, they are a rather extremist outfit, IMO.

        1. JohnSprung | Jan 04, 2006 04:22am | #16

          Would one of those filters that attach to the faucet help with lead?  

           

          -- J.S.

           

          1. User avater
            BillHartmann | Jan 04, 2006 04:56am | #18

            Some do.I have not looked at the specs on this, but hve on the under counter units.They come in 2 flavors for filtering - basic taste and "deluxe" which list a large number of compounds and percentage that they remove. IIRC lead is included.

      3. WayneL5 | Jan 04, 2006 04:37am | #17

        Lead can be quite damaging to infants.  You should confirm the lead level with a laboratory test.  In the mean time, I would not serve anything containing or cooked in that water to children.  You ought to use bottled water from today on until you know with testing the water is low in lead.

        Mention it to your doctor at her next checkup.

      4. plumbbill | Jan 04, 2006 07:14am | #19

        So my pipe appears to be lead, magnets don't stick to it

        Holy crap it's lead?

        Get rid of it now.

        Does it mar real easy with pliers or channel locks?

        Yes you can solder (wipe was the term back then) to copper----I wouldn't if it was my house--- but I have done it big pain in the azz.

        How much is there? Can you replace where it comes in the house? ( yes I know it's the wrong time of the year)

        Ok let's say you can't get rid of it now, you can use a dresser coupling that goes around the pipe like a compression coupling they make them for any different sizes out there pretty much.

        Yes they have filters for lead removal.

        http://www.aquapurefilters.com/store/

        http://www.everpure.com/

        http://www.keystonewaterfilter.com/home_h_1.htm

        I mainly use aqua & everpure filters

        Aqua for residential & everpure for starbucks + my house

        1. pjmcgarvey | Jan 04, 2006 06:08pm | #20

          Well, it's not copper, and doesn't appear to be galvanized, so it sounds like lead is the next obvious choice?  Are there any other non-ferrous metals used for pipe?

           

          It comes in the house through a rubble stone foundation probably about 4 feet below grade.  I've replaced pipe that I can access in the basement for the kitchen, bathroom, etc. but there is probably about 100 feet of it, hot and cold, in the basement. 

          We only drink water from a pitcher filter, but after I replace all the pipe with copper, I'm going to install a water softener, and I guess it would be a good idea also to add one of these filters as well...

          PJ

      5. pjmcgarvey | Jan 04, 2006 08:27pm | #21

        I found another recommendation on how to transition from lead to copper:

        http://aymcdonald.com/ProdImages/Water/cad/4758C66.pdf

        It's an all-brass piece, for use with potable water, and fits 3/4" on both new and old pipe.  Sounds like a win-win. 

        Has anyone used something like this and have any install suggestions, especially for threading the end onto the lead pipe.  Teflon tape a good idea for all the threads?

        Thanks,

        PJ

        1. dgbldr | Jan 04, 2006 09:53pm | #22

          OK, several issues here:

          1. Have your infant tested for lead.  Your local community health agency can tell you where and how.  It's relatively inexpensive and you'll sleep better. Lead accumulation in the body is irreversible. Also, in a house that old you have lots of lead in the wall paint. Careful not to sand walls, etc. Do a lot of research before any demolition/remodeling.

          2. Now that you know it's lead, get rid of it. When you sell the house, you'll have to disclose it and it will lower the value of the house.

          3. Transitions are available in many flavors. Dielectric ones are the only ones completely corrosion-proof. They have a plastic part in the middle.

          4. Since you are not a plumber, stay away from compression fittings. They can let go later if installed improperly.  I have redone several basements after flooding from a DIY compression job.

          5. Unless you are unemployed, get a good plumber. It will cost you less than the value of the time you are spending on this forum alone.  If you want to learn plumbing, this is not a good beginner project.  Not trying to be rude, just honest.

          DG/Builder

          1. User avater
            aimless | Jan 04, 2006 11:29pm | #23

            "Dielectric ones are the only ones completely corrosion-proof."

            That's interesting. We had a plumber replace some deteriorating galvy with copper, and the dielectric union he used started corroding after a couple of years. Did we just get a bad fitting, or was he lying?

             

            To the original poster - if it was me I would not proceed without at least getting an estimate for replacing the lead pipe. It might not be as expensive as you think, especially if you factor in the cost of a lifetime of health problems that lead can cause.  And I wouldn't really trust a cheesy filter in the interim. I'd switch to bottled water or invest in a real filter.

          2. dgbldr | Jan 05, 2006 12:01am | #24

            Depends.  Dielectric unions protect against galvanic corrosion (dissimilar metals in direct contact).  Copper and galvanized can corrode for a number of other reasons.  As you found out when you replaced your "deteriorating galvy".  The galvanized part of the union is no different than any other galvanized pipe or fitting.  Except yours could have been of poor quality, i.e. very thin galvanizing (zinc).  Or not dielectric.

            DG/Builder

             

          3. JohnSprung | Jan 05, 2006 02:36am | #25

            I, too, had dielectric unions fail.  Replaced them with braided stainless between the copper and galv, which is lasting much better.  

             

            -- J.S.

             

          4. plumbbill | Jan 05, 2006 02:47am | #26

            3. Transitions are available in many flavors. Dielectric ones are the only ones completely corrosion-proof. They have a plastic part in the middle.

            I have a couple of issues with that.

            I have replaced failed rubber washer on those more times than I care to remember.

            In our neck of the woods if we use them the inspector will make us put a jumper wire to maintain ground continuity.

            We have switched to brass nipples atleast 6" long & dieletric nipples Clearflow¯ & Victaulic¯ are the two major ones we use.

            They are a zinc coated iron nipple with a plastic liner on the inside & the first two threads.

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