Copper Coat

[stevemid]

Originally Posted by redbopeep

I'm becoming really interested in how muddy the water is where people are who are having problems. The dirt in the water has high iron content and the iron creates a black oxide that is inert (and thus isn't good antifouling) whereas normal saltwater gives that brighter green oxide that is active (creating the good antifouling).

Thanks so much for giving your reports and our fingers are crossed that you did indeed allow enough copper to show that it will create the oxides to do antifouling properly.

I'm in Sydney Harbour. When it rains the water is very muddy for a few days as much sediment is flushed into the Harbour. After a few days, the sediment settles out and the water is crystal clear. I'd estimate we have muddy water maybe 5% of the time. My coppershield above the waterline is green; below the waterline a blackish green prior to the 600 grit treatment.
Steve

[redbopeep]

I really don't know the proper color of the green--but when we were in the muddy waters of the SFBay area (and we're back!) it became quite blackish and we'd use the brown scotchbrite "doodlebug" to scrub it off underwater to get back to greenish green Hope that helps.

Regular bottom paint has the cuprous oxide (don't know if that's the right spelling and oxide...) rather than copper in it. That is why it doesn't last as long as the coppercoat which does have copper in it that slowly oxidizes. So--if the oxides are happening in the presence of the iron, it just turns out a little "different" I suppose.