On Jan 22, 3:38*pm, wrote:
On Sat, 22 Jan 2011, RicodJour wrote:
On Jan 22, 1:59*am, David Nebenzahl wrote:

Now *that* makes my BS meter twitch just a mite: why would there be
corrosion? Galvanized pipe is zinc over steel, so galvanized + steel
(black) should be no problem, right?

Time to recalibrate that meter, kimosabe. *Zinc is used as a
sacrificial anode in boats for the very reason that it will corrode
first and protect the iron.
http://www.mikeholt.com/mojonewsarch...alvanic-Action...


YOur BS meter needs recalibrating. The ZINC may corrode, but that is
not an issue here. It is a very thin coating on one surface that is
beinf threaded to another (identical) surface. NOT an issue. Period.

Why would the zinc corroding not be an issue?
If you have a galvanized pipe and the coating is compromised in any
way, the corrosion will be concentrated at that point, right?
Why do gas companies and many codes prohibit using galvanized fittings
in gas lines?
Why do you feel that your apparently Pope-like-infallible opinion of
your opinion is at issue with those utility companies and AHJs?
You are familiar with sacrificial anodes, of course, and you do
understand that the more reactive metal will corrode more quickly in a
mixed metal situation, and you do know that not all gas is totally
pure, may contain water, that there are recommendations for having
traps to catch the water, but that the traps are not always present -
so why the blanket certainty over a very uncertain situation?
Oh, right - it's not your house.

Here's a possible repercussion that makes your opinion moot. A home
inspection. If a home inspector flags a galvanized fitting as being
against code, the homeowner will end up paying for it, and it will be
more than just the price of the fitting. The OP's theoretical attempt
at saving himself a trip to a more fully stocked supply house will
cost him more in the long run. Perhaps you're banking on the OP being
dead at that point, and it no longer being his concern, but I don't
take such a short-term view of the situation.

I am not saying that the potential problem with using a galvanized
fitting or whatever is necessarily a serious problem, nor is it
inevitable, simply that there is NO benefit to mixing galvanized and
black iron and it will raise concern, and increase the risk of a
problem, no matter how small that risk is.

So, to sum up, there is NO benefit - the galvanized costs more, it
will bother some people and some of those people are in a position to
tell you what to do with your house. So what exactly is your
reasoning that it's better to go with galvanized?

R