Originally Posted By: jbilski This post was automatically imported from our archived forum.
Home has copper water piping. In basement water lines are secured with copper hangers. Major corrosion (green/crusty) where the piping meets the hangers. So much so, that they are all fused together. Any ideas why this would happen with two similar metals…copper against copper?
Originally Posted By: gbeaumont This post was automatically imported from our archived forum.
Hi to all,
I think you guys are on the wrong track, when I looked at the photo (after a 10 min down-load  ) what I saw was what I believe to be a copper plated steel hanger, the lower part of which is showing significant rusting (look at the scaling typical for steel). I think that what has happened over the years is that vibration on the pipes wore through the copper plating to the point that moisture was able to start to act on the steel, both rusting the hanger, and producing a galvanic reaction between the 2 dissimilar metals.
Originally Posted By: jpeck This post was automatically imported from our archived forum.
I think Gerry has nailed it. First give-a-way was those wire hangers, if plain copper, then would tend to bend flat when driven in. They would need to be cast copper or brass to not crush, or copper coated steel, and they are not ‘cast’ anything, but drawn wire and bent into the hanger and spike shape.
I think the silver / white stuff is corrosion powder, where the pipe may be getting ready to leak through.
Originally Posted By: jsavino This post was automatically imported from our archived forum.
Look at the picture again, the pipe hangers are made from two different matierals. Thats why there is rust. Flux is an acid made to etch into the copper to bond the solder and the cooper for a strong joint. The flux was never wiped off after it was soldered and after time oxidation will form on the pipe. Look at the top of the pipe. It is not in contact with the hanger.
From the back of the can of Utility Flux "Wipe off excess after soldering. Fill system with water as soon as possible to rinse away any flux residue."
Get a piece of copper pipe, wipe flux on it and put it on the shelf. In time the flux will turn green with oxidation.
-- John Savino
HomeWorks Inspection Services, LLC
St. James, NY
631.379.4241
Originally Posted By: jbilski This post was automatically imported from our archived forum.
John,
I would agree with the solder theory except for one thing. This was an area of straight piping. There were no solder joints. It looks like the corrosion worked it’s way around the piping from the dissimilar metal contact of the hanger. Unless…the installer soldered the hangers to the pipe. Seems like a lot of extra work to solder all these hangers, but who knows.
Thanks for all your help guys.
I'll keep my eye on these hangers 
