How To Join Galvanized Pipe
Galvanized steel pipe was the mainstay for residential plumbing for decades. Copper pipe was available alongside galvanized but it was more expensive and used primarily on higher end projects. Copper is still used, and now plastic pipe is much more common, but galvanized is not used as much anymore. A lot of the fittings you see in the hardware store are used for repairs more than new projects.
If you need to join galvanized pipe, we'll explain how it is done. However, if you want switch to copper or plastic to make repairs, you can do that, but you will need to employ some specialized fittings to make the transition. For instance, to connect copper pipe to galvanized steel pipe, you need to use a dielelctric union to prevent the corrosion that occur between dissimilar metals.
Joining galvanized iron fittings to galvanized steel pipe requires pipe dope or Teflon tape and two pipe wrenches.
Start by liberally coating the threads of the pipe with pipe dope or wrapping the threads with Teflon tape. Make sure the pipe joint compound or tape go into the threads, to ensure a water tight connection. You can also apply some pipe dope to the interior threads of the fitting.
Next, thread the fitting onto the pipe and hand tighten. Place a pipe wrench over the pipe, a few inches from the fitting and tighten down the wrenches jaws. Place the second pipe wrench over the fitting and tighten it onto the fitting. Now, while holding one wrench in place, use the other wrench to tighten the fitting onto the pipe.
Generally, with steel pipe, you will tighten it down about as tight as you can get it. There is little risk of cracking a pipe or fitting using your arm strength. However, using long levers to increase torque can lead to metal failure. Don't worry if some threads are still visible at the connection, that is normal.
Pressure test your joints before closing them up or otherwise making them difficult to access.