Copper 3" Drain Pipes

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gpcollen1

Minister of Fire
Oct 4, 2007
2,026
Western CT
I just had to deal with a flood in my downstairs bathroom and laundry room. Long story short, about 5 joints out of 25 in the copper were corroded to heck with that green crap all over the joint on the pipe side. Some of the joints look as good as new - except for those 5 joints. I ripped out what I had to and plumbed in with ABS.

What the heck caused the issue on those pipe joints??
 
I suppose if water sat in them for too long that could happen. Copper corrodes quite quickly when exposed to air and water (hence why water pipes do ok, being they should be totally full of water). Didn't realize people even used copper for drain pipes...
 
maybe some bad soft copper ?
I've had some old drum traps and 3 " copper pipes ( maybe bronze) that were from the 20ies. Pretty solid stuff.

If rotted from the outside maybe a really damp basement or location ?



I've had horizontal runs of the old cast iron pipe go bad. Always rotted out on the top part of the pipe, not the bottom where the water ran. ( you could watch "stuff" going by whenever a toilet was flushed ).
 
This is sewer, the sewer gasses are corrosive and will burn out metals that are sensitive to corrosion. We have trouble with the sewer gasses on the mainlines too, it will even eat up concrete. As this happens we replace with various forms of poly.

My home was built in the early 60s and is equipped with all hard copper drain lines too. They are connected with brass (bronze) fittings and soldered. All is copper, even the little 1.5" stuff near the sinks. When I replaced my power panel I had to ground the hot water, cold water, ground rods in the dirt, and also the drain pipes since they were conductive.
 
They were probably soldered with too much, or too strong, acid flux. Some fluxes are too aggressive for copper piping, since they don't stop etching the metal. I've seen that happen with electronic items, too, when someone uses acid flux instead of rosin flux.
My parents' house had copper waste plumbing, built in 1958, never had a problem. Sold the place 5 years ago.

I had a supply pipe leak when it developed a pinhole in it, and it sprayed water around for a while. When I examined the pipe, there was a nodule on the inside, blocking a lot of the flow, and the pinhole. Turns out the phone company used that pipe for a ground near that spot, and the electrolysis ate the pipe. It took about 40 years to do it, though.

If you repair the pipes yourself, here's a little tip: there always seems to be some water dripping down the pipe, no matter how well you drain them. Take some white bread, ball it up, and stuff it in the pipe. It will stop the dripping long enough to solder the joints, and when you turn the water on, the bread will just flush away.
 
heat seeker said:
They were probably soldered with too much, or too strong, acid flux. Some fluxes are too aggressive for copper piping, since they don't stop etching the metal. I've seen that happen with electronic items, too, when someone uses acid flux instead of rosin flux.
My parents' house had copper waste plumbing, built in 1958, never had a problem. Sold the place 5 years ago.

I had a supply pipe leak when it developed a pinhole in it, and it sprayed water around for a while. When I examined the pipe, there was a nodule on the inside, blocking a lot of the flow, and the pinhole. Turns out the phone company used that pipe for a ground near that spot, and the electrolysis ate the pipe. It took about 40 years to do it, though.

If you repair the pipes yourself, here's a little tip: there always seems to be some water dripping down the pipe, no matter how well you drain them. Take some white bread, ball it up, and stuff it in the pipe. It will stop the dripping long enough to solder the joints, and when you turn the water on, the bread will just flush away.

Great tip with the bread, and also spot on with the flux comment. Acid flux can be a big problem. I don't do a lot of plumbing, but I am an amp tech for a local music shop in town and always hear horror stories of people "repairing" their own electronics with acid flux....not good.
 
Back in the day when Heathkits were popular, they would occasionally get one returned that had quit working. The kit builder had soldered all the connections with acid core solder - turned the stereos into expensive doorstops. An expensive lesson for the kit builder! The repair techs would not touch them, they knew that they'd never get them fully straightened out.
 
Thanks for the thoughts folks. The house did sit relatively empty for a few years before I bought it almost 10 years ago - built in 1972. It was the fact that the other joints around there were in such good shape that confused me. Now that I think about it, most of the corrosion was in the horizontal run from one of the toilets. The lines from the sinks, shower and tub were fin as well as the down pipe from all of them.
 
kettensäge said:
Take the old copper pipes to the local recycler, you might make enough to pay for some or most of the new ABS

And a 10 day cruise!
 
kettensäge said:
Take the old copper pipes to the local recycler, you might make enough to pay for some or most of the new ABS

You bet your arse! Copper pipe and brass fittings. Probably about 30 pounds worth...but i might lose 5 pounds or so cleaning them a bit.

EDIT: Just looked and the copper is around $4 per pound...yeah...
 
Were the joints leaking or just covered in verdigris? Depending upon the care with wich they were soldered, staining is neither unusual nor dangerous.
 
Czech said:
kettensäge said:
Take the old copper pipes to the local recycler, you might make enough to pay for some or most of the new ABS

And a 10 day cruise!

+ 1
 
Dune said:
Were the joints leaking or just covered in verdigris? Depending upon the care with wich they were soldered, staining is neither unusual nor dangerous.

The pipe at the joints was falling apart - not stained.

Not sure but there is BX that runs over the pipes. If one of them was touching the pipe, could that have caused this?
 
In my opinion, yes. I had a water pipe that was used for the telephone ground. The pipe developed pinholes and started leaking near where the clamp was. When I examined the inside of the pipe (after cutting it out), there was a nodule inside that was restricting the water flow, as well as the pinholes. I forget the name of the process (electrolysis?), but it removes metal from one area and moves it to another via small electric currents, such as a ground loop. I soldered in a new section, and moved the ground to a ground rod outside.
 
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