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  • Copper/steel corrosion

    Hi,

    I have a question about what happens when copper water pipe comes in contact with galvanized steel. For example, nailing plates or steel studs.

    Some say it's the steel that will corrode, and some say it's the copper that will corrode.

    Does this contact cause corrosion? If so, how common is this problem? Are you plumbers out there constantly fixing this?

    Thanks,
    Frank

  • #2
    Re: Copper/steel corrosion

    have a read through this thread
    http://www.ridgidforum.com/forum/showthread.php?t=22120

    it might not answer all of your questions, but it's a good knowledge base.
    No, it's not rocket science, it's plumbing and unlike rocket science it requires a license.

    Comment


    • #3
      Re: Copper/steel corrosion

      I know that when I replace water heaters that have galvanized nipples and copper flex lines the nipples usually full of corrosion. It is better to put a non conductive layer in between.

      Comment


      • #4
        Re: Copper/steel corrosion

        Copper can sit on galvanized unistrut and be anchored with steel unistrut clamps. If it rubs against steel or another metal, it can wear a hole in it.

        Comment


        • #5
          Re: Copper/steel corrosion

          Originally posted by FSK View Post
          Hi,

          I have a question about what happens when copper water pipe comes in contact with galvanized steel. For example, nailing plates or steel studs.

          Some say it's the steel that will corrode, and some say it's the copper that will corrode.

          Does this contact cause corrosion? If so, how common is this problem? Are you plumbers out there constantly fixing this?

          Thanks,
          Frank
          ....i've had issues with the so called copper straps that are used to anchor copper tubing to a joist or stud. they can and will develop pin holes under the strap. especially if it moves slightly under the strap. the reason is because the copper straps are STEEL coated with a thin layer of copper. (just check 'em with a magnet if you have doubts) when the 'layer' rubs off you then have steel against copper thus a breeding ground for corrosion. been there done that.

          Comment


          • #6
            Re: Copper/steel corrosion

            Originally posted by FSK View Post
            Hi,

            I have a question about what happens when copper water pipe comes in contact with galvanized steel. For example, nailing plates or steel studs.

            Some say it's the steel that will corrode, and some say it's the copper that will corrode.

            Does this contact cause corrosion? If so, how common is this problem? Are you plumbers out there constantly fixing this?

            Thanks,
            Frank
            The copper should be isolated. I use 10 mil. tape.

            Comment


            • #7
              Re: Copper/steel corrosion

              Everyone should have the www.copper.org website bookmarked.

              Read this article:

              http://www.copper.org/applications/p...r_systems.html

              Look at the table and see how far apart Copper is from Galv. Steel are.

              As far as direct contact between copper and unistrut or other steels, painted, galvanized, or otherwise, my opinion is it is best to insulate between the two to prevent galvanic action from taking place.


              Another thread on the subject here on the Forums.
              http://www.ridgidforum.com/forum/sho...pper+corrosion
              Last edited by Bob D.; 04-26-2009, 10:49 AM.
              ---------------
              Light is faster than sound. That's why some people seem really bright until you hear them speak.
              ---------------
              “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
              ---------
              "Its a table saw.... Do you know where your fingers are?"
              ---------
              sigpic http://www.helmetstohardhats.com/

              Comment


              • #8
                Re: Copper/steel corrosion

                It's funny that the inspector will look right over the lowly escutcheon.

                Comment


                • #9
                  Re: Copper/steel corrosion

                  Originally posted by stokefire7 View Post
                  It's funny that the inspector will look right over the lowly escutcheon.
                  If they were stamped from copper sheet and chrome plated (or less expensive faux chrome plastic) there would be no problem.
                  ---------------
                  Light is faster than sound. That's why some people seem really bright until you hear them speak.
                  ---------------
                  “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
                  ---------
                  "Its a table saw.... Do you know where your fingers are?"
                  ---------
                  sigpic http://www.helmetstohardhats.com/

                  Comment


                  • #10
                    Re: Copper/steel corrosion

                    Bob, there magnetic, I checked.

                    Comment


                    • #11
                      Re: Copper/steel corrosion

                      Originally posted by stokefire7 View Post
                      Bob, there magnetic, I checked.
                      I didn't say they weren't, and I am well aware that most of those sold today are not.

                      I said we would be better served by ones that were made from compatible (or electrically neutral) materials.
                      ---------------
                      Light is faster than sound. That's why some people seem really bright until you hear them speak.
                      ---------------
                      “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
                      ---------
                      "Its a table saw.... Do you know where your fingers are?"
                      ---------
                      sigpic http://www.helmetstohardhats.com/

                      Comment


                      • #12
                        Re: Copper/steel corrosion

                        Thanks for all the posts. After reading some of the articles and threads posted, I have more questions.

                        I looked at a couple of grounding cables that are attached to my pipes and wire is copper and the clamps on them are made of galvanized steel. Same with the connector for the humidifier supply value attached to one of the pipes. It's made of galvanized steel. These things look like they have been there for a while, (I'm guessing since the house was built approx 45 yrs ago) and there doesn't look like any corrosion to the pipes.

                        Also, some of the articles are saying that this electrical circuit that causes the corrsion is complete when both metals are exposed to water. Does this mean that without exposure to water (the situation I'm talking about is outside the pipe), the corrosion is less severe?

                        Thanks,
                        Frank

                        Comment


                        • #13
                          Re: Copper/steel corrosion

                          yes it is like a car battery you need the acid to create the electrolysis. Water has minerals and a ph level that helps the corrosion along.

                          Comment


                          • #14
                            Re: Copper/steel corrosion

                            ITS BEST TO AVOID ANY CROSS METAL CONNECTION WHEN NOT PRACTICAL USE A DIELECTRIC NIPPLE OR UNION. ALSO READ THE CODE ABOUT THIS SITUATION. LIKE YOU SAID I SEE THIS ON WATER HEATER REPLACEMENTS AS WELL GALV. NIPPLE BETWEEN TO CT. FLEXES OR CONNECTED TO TANK. IF YOU ARE SEEING THIS AT WATER HEATER WHATS HAPPENING IN THE REST OF THE SYSTEM.

                            Comment


                            • #15
                              Re: Copper/steel corrosion

                              Originally posted by LayinPipe View Post
                              ITS BEST TO AVOID ANY CROSS METAL CONNECTION WHEN NOT PRACTICAL USE A DIELECTRIC NIPPLE OR UNION. ALSO READ THE CODE ABOUT THIS SITUATION. LIKE YOU SAID I SEE THIS ON WATER HEATER REPLACEMENTS AS WELL GALV. NIPPLE BETWEEN TO CT. FLEXES OR CONNECTED TO TANK. IF YOU ARE SEEING THIS AT WATER HEATER WHATS HAPPENING IN THE REST OF THE SYSTEM.
                              Thanks for the info, but it really doesn't apply to what the original post is asking. There are no galvanized to copper connections, it's about galvanized metal studs coming in contact with copper and what happens (if anything).

                              Comment

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