I have a di-electric union which I want to install, but the union's galvinized side is threaded. The unthreaded, galvanized pipe is attached to the house so I can't easily thread it.

Perhaps there's some better way to connect an unthreaded 3/4" galvanizeded pipe to a 1/2" copper water line?

  • What are you wanting to run through the pipe? Jun 10, 2016 at 15:18
  • It's a cold water line supplying my bathroom sink. The copper is supply and it meets the unthreaded, galavanized under the house in the crawl space. I'm wanting to connect the two.
    – zundarz
    Jun 10, 2016 at 16:10

1 Answer 1


You have 3 or more options. #1 get a shark bite to go from galvanized to copper. #2 You need to go to a plumbing store and get a galvanized nipple and then extend your copper to the point the pipe screws into a coupling or other fitting. #3 If you don't want to extend your copper get an exact measurement and have a new piece of pipe cut and threaded. #1 is the easiest way and may be the most expensive but what you save in time is worth it. I may have used a Dresser compression fitting home depot calls them pattern fittings for galvanized repair in the wall I could not thread or remove but thought it was a shark bite.

  • Thanks noting that there is sharkbite for galvanized. I thought it was only for copper.
    – zundarz
    Jun 9, 2016 at 22:11
  • 2
    Sharkbite is not designed to go over a unthreaded galvanized.
    – Damon
    Jun 10, 2016 at 1:47
  • Is there anything I can put on unthreaded galvanized? Or am I going to need to thread it?
    – zundarz
    Jun 10, 2016 at 13:27
  • Couldn't you attach the dielectric directly to the compression fitting instead of a nipple? Or could you attach a reducing coupling to the compression fitting so that the dielectric can be attached without a nipple? Jun 10, 2016 at 15:26
  • I can't find any sharkbite-style fittings for galvanized or black iron... Jan 28, 2019 at 23:50

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