The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.
Fencepost: You said:
I guess that depends on how much emphasis you put on that word "eventually".But copper, too, will eventually corrode when exposed to moisture and oxygen.
The reason why we presume that most metals corrode is because iron is so prevalent in our culture and society, and it rusts. Iron is actually very different than most metals in that the oxide film it forms neither protects the underlying metal from further rusting, nor does that oxide layer bond to the underlying iron metal.
With the sole exceptions of g-o-l-d and platinum, all metals rust, but the oxide film they form is typically highly impermeable and bonds tenaciously to the underlying metal. Consequently, as that oxide film grows in thickness, it better and better protects the underlying metal from further oxidation.
Copper is a familiar example. New copper piping is a metallic orange in colour. Copper oxide is brown in colour. That's why new copper piping turns brown over the course of a few years. Ditto for pennies.
However, anyone that's ever done any plumbing knows that it doesn't take much more sanding to sand that brown oxide film off a pipe that's been in service for 60 years as opposed to one that's only been in service for 10 years. That's because the oxide film layer on the 60 year old pipe isn't 6 times as thick. It's probably not even twice as thick.
The dissolved oxygen in the water results in the same protective oxide film forming on the inside of the pipe as well.
To say that copper pipes will eventually corrode is misleading. It implies that this is something that one should expect to happen within the lifespan of the house, when really you're talking about tens (if not hundreds) of thousands of years.
1. Steel is iron with a bit (typically less than 1 percent) carbon in it.
2. Both chromium and nickel form a protective oxide film like most metals do. It was the high chromium and nickel content in early stainless steels that prevented them from rusting. "18-8" stainless steel is so named because it's chromium and nickel content is 18 and 8 percent, respectively. However, both chromium and nickel's oxide layers are much more impermeable, and therefore don't grow as thick as the oxide film on copper. The oxide layer on chromium, nickel and stainless steel is in fact so thin as to be invisible. Chromium oxide and nickel oxide are both green in colour.
3. In ancient Egypt, the symbol for copper was the ankh; the same symbol used to denote eternal life. The Egyptians that built the pyramids were undoubtedly aware of copper's natural resistance to corrosion to have associated it with eternal life.
Last edited by Nestor; 06-12-2011 at 03:36 AM.
The cheaper thinner walled (M) copper which is only used on non pressurized lines now, because of its proven pin hole past and not lasting the test of time. Was legal 15 years or later for presurized water line installation and sorry to your misfortune you are seeing its wrath, my apologies.
The (L) and (K) type copper piping are the standard now and will last 40, 50 plus years with out problems as long as the piping is reamed and secured correctly from abrassion and movement.
(L) copper is twice as thick as M copper and (K) copper twice as thick as L, I personally, (been plumbing for over 30 years) prefer copper piping over Pex for its sturdiness, rigidity and hard to puncture qualities. Pex is great for radiat floor heating, (its buried in floor leveler, protected) and Trailers. The security of welded fittings and Puncture resistance is my professional choice.
Copied from a previous post I made on :Leaking Pipes"
Great arguments for and against PEX, great arguments for and against copper.
To sum it up: would you trust your drinking water to PEX/plastic?
I won't. For irrigation, bathing, washing and flushing - yes. For drinking - no.