Putting Copper Under Wraps
I was on my way home from the There’s Water Under the House job when the phone rang. A do-it-yourselfer had gotten himself into a fix. The copper water main under his house had developed a pin-hole leak. He’d tried to fix it himself, but couldn’t get any of his patches to hold. He’d tried solder couplings and compression fittings and had finally thrown up his hands in despair. It was already four-o’clock. In an hour all the hardware stores would be closed, and these people had no water.
Upon inspection the problem didn’t seem that difficult. We needed a few feet of copper, a stopless coupling, and an FIP to copper adapter.
Then I looked at the rest of the copper under the house. It was green and dark brown. Classic signs of electrolysis. Putting new copper pipe up to this old stuff, I could see that half the wall thickness of the pipe had been eaten away. When I hit the old copper pipe with emery paper, I could easily see how pitted it was. Under a microscope it would have looked like the surface of the moon. In some places the old pipe had to be paper thin. In any event, I knew that getting the solder to take and fill all those voids was going to be hard. A dice roll, in fact.
It almost worked. One pin-hole in the new solder joint was all there was. I was actually pleased, but not out of the woods. The leak was entirely too big to let go until the bigger plumbing problem could be addressed. So I pulled an old "fisherman’s trick" out of my hat. You can use it too:
With the water off I took a strip of rubber — an old inner-tube split down the middle and then cut into strips about an 1½" wide will do — and wrapped it around the pipe so as to make three layers of rubber over the pin-hole. Then I clamped the rubber into place with a couple of pipe clamps. When we turned the water on, it didn’t even drip! (I’m sorry I didn’t get a chance to take pictures of this for you. This was a rush job so there wasn’t time. Maybe I’ll get a chance to do a demo for you some time.)
Give it a try next time you have a pin-hole leak in a pipe.
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