Well you all forced me to go dig out my old Calder (actually it is a new one, my old one wore out).
Calder recommends against bonding bronze thru-hulls and other bronze plumbing so long as they are isolated from other metal components or not immersed in seawater that could contain stray electrical current (e.g., the bottom of the bilge). His reasoning is that bronze is so much more noble that most other metals that may be bonded to the zinc that the bronze will only accelerate the destruction of the zinc then the destruction of the bonded metals that the zinc was supposed to protect.
That seems to let me off the hook for my manifold, except he goes on to recommend against bronze ball valves with SS balls (my Grocos).
I've decided to exercise my right to selectively accept the advice of experts. So I'll stay with my unbonded manifold with SS ball valves. I'm pretty comfortable with the latter position as it appears all of the original valves on my 424, with the exception of one, are bronze ball valves with SS balls. The one exception is the valve for the deck scupper under the aft berth. That is a true bronze seacock. Having lived on board for nearly 5 years and cruised for 3 years I got out of the habit of closing and opening the valves on a regular basis. This year before my haulout I found nearly all were frozen so during the haulout I worked on all of the valves. Power washing the hull freed up most of them – just a few barnacles on the ball. Others only required a light tap with a hammer to open. I checked the balls in all of these valves and could see no deterioration. If they have lasted with about zero maintenance for 30 years I'm not worried about the valves I just installed.
Anyway that's my rationale and I'm sticking to it :).
On Tue, Sep 16, 2008 at 8:26 AM, Silver Heels < ([email][/email])> wrote:
seawater so no strapping is necessary. The plot thickens.
I'd be surprised if a home sprinkler system was made of bronze or stainless steel. Seems like an unnecessary
extravagance, but would be delighted to learn otherwise.
Tor
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Silver Heels, P-424 #17
http://www.SilverHeels.us
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