Subject: Re: [harryproa] Re:: Flat bottom hulls? / fouling |
From: "Mike Crawford mcrawf@nuomo.com [harryproa]" <harryproa@yahoogroups.com.au> |
Date: 11/13/2018, 3:04 PM |
To: harryproa@yahoogroups.com.au |
Reply-to: harryproa@yahoogroups.com.au |
Two things to clarify.
A. Leaching copper does damage marinas.
In some crowded marinas, filled with boats using paint with
cuprous oxide, the copper level can reach points to where marine
life is damaged. This is why the U.S. and others are working to
limit it. This happens because the oxide form of copper leaches,
and while this does help with antifouling, it also puts a lot of
copper into the water while also reducing the useful life span of
the paint.
B. Copper metal is non-leaching.
The powder, flakes, and micro-spheres used in copper/epoxy
coatings like CopperCoat is non-leaching physical metal, so it does
not face the same limitations as cuprous oxide. While a leaching
paint drives away growth with the copper leaching out, it's the
actual copper surface with solid copper that they can't or won't
stick to. You could say this is marketing hype, but it stands to
reason: If all the copper were to leach out of the paint in 24
months, there's no way the surface would still be antifouling five
or ten years later.
- Mike
| The amount of copper, 2/kg per litre of resin is the maximum amount allowed by law.
https://www.yachtmollymawk.com/2012/04/search-for-effective-environmentally-safe-antifoul/3/
As pointed out in the link, I can find no source for coppercote's claim of a legal limit of copper per liter of epoxy.
Upon reflection, I think it's silly to worry about the copper when the copper is in solid water immersed BPA!
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