Join Date: Jul 2019
Location: Maryland and Florida, boat is in Pasadena, Maryland
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Bronze matching necessary?
I have replaced a 1.5 inch valve and thru hull, after only a few months in brackish (upstream Chesapeake) water there's green verdigris on both near connection. Hard to believe its leakage, was very careful with thruhull installation and used Sikaflex 291 long setting, but I am fairly new to the procedure - have done half a dozen and there's no evidence of leakage on any of them. I did connect a bonding wire to the valve, have not yet installed a galvanic isolator. She was in the water when it froze over, but bubbler/circulator kept most ice away from the hull. Also note that the valve has never been connected to any plumbing at all.
Two questions - could this be galvanic corrosion due to metal mismatching? Valve is Groco IBV 1500, 400 WOG, don't know what the thruhull is. If it is, how does one go about matching metals on thru-hull and valve? What else am I missing?
Second, if its leakage, should I also be worried about osmotic action in the hull itself? I cleaned and scraped the hole but didn't prep it with anything - should I paint the hole with epoxy or something before installing the thru-hull?