Adding copper dust to bottom paint

[lateral]

Originally Posted by a64pilot

Back to my first post where I said many people drink water from copper pipes.
So why is it so many think copper is a Biocide? If it were, do you think making drinking water pipes out of it would be smart?

Because copper oxide/salts ARE biocides. Weak ones.
And Cu forms oxide & salts in seawater.
As defined by chemists/marine biologists.
FB summary best fits.

Thing is, peoples expectation of an AF performance varies widely,
Performance to initial cost+maintenance ratio.
Bit like the FLA battery dance.

[a64pilot]

Copper salts yes, but does that necessarily relate to copper?
Not trying to be cute, but to be an effective antifoul it pretty much has to be either so slippery life can’t attach, or be some kind of poison.
I’m just not sure copper is a poison, copper reacted with other elements, yes, but pure copper?
I know you can take a piece of copper pipe, put it in water and stuff grows on it just as well as it grows on anything else, I have tried it.
So I scratch my head on how copper coat is supposed to work.

It seems copper is indeed a biocide, so why do we drink water and cook in copper utensils?
If it’s so deadly to marine organisms, it would seem to be a stupid thing to do?

[svlamorocha]

Originally Posted by a64pilot

I know you can take a piece of copper pipe, put it in water and stiff grows on it just as well as it grows on anything else, I have tried it.
So I scratch my head on how copper coat is supposed to work.

Coppercoat works great if you liveaboard in the tropics and don't mind cleaning the hull at anchor every other week. It needs (and can bear) very aggresive cleaning with 3M pads. If you leave a copper pipe underwater in the Caribbean and scrub it every other week nothing will grow on it AND survive the scrub. Horse for courses...

[lateral]

That's why AF manufacturers use Cu2O and not the metal .
Cu metal once submersed, formes Cu2O a lot slower than in air. I guess that is why it is not a problem in pipes. Also
the relative body mass.
Anyway, it doesn't fit my def of an AF or FR.
Waiting on ptfe, pdms, peg derivatives for a
slippery disguised hull , anti- marine habitable.

[44'cruisingcat]

Originally Posted by a64pilot

No.
I don’t believe copper is necessarily a bad thing environment wise.
Many of us drink water from copper pipes.
There are a lot of home brew additives people will put into bottom paint, like cayenne pepper. I don’t think any of it does much, and may mess the paint up.

Yep. A friend was advised to add copper sulphate crystals. It didn't dissolve and his antifoul looked more like anti skid.

[lateral]

CuSO4 is water soluble Good luck with that it will be gone before you know it. You have to saturate a solution to crystalize..

[a64pilot]

I’m thinking anything would stay free of growth with an aggressive scrub every 14 days.

[lateral]

Originally Posted by a64pilot

I’m thinking anything would stay free of growth with an aggressive scrub every 14 days.

Darn right!
Would be good for the body.
Putting off doing my dive/ hullscrape, 15° water; knowing its going to be a chisel fest.

[Steve Bean]

Water chemistry determines whether copper leaches into the water in the pipes. I have survived over 20 years in the drinking water business. Some water erodes copper, some leaves a mineral deposit which in some cases can build up enough to reduce flow. I am about to repipe my 40-year- old house because pinhole leaks are occurring. The EPA sets a limit on copper in drinking water. Water suppliers over a certain size are required to treat the water to control leaching.

[sand6000]

If you want more copper then check the antifouling label for the concentration and go with the one that has the most. Also check with other boats in your are and see what is working best.

[thinwater]

Originally Posted by Jim Cate

The above is completely correct!

In some waters, copper sheathing will keep growth down, but in most it is ineffective as antifouling, and I think this is reflected in the spotty success of coppercoat that is reported. If without gaps, sheathing is completely successful at repelling Toredo (sp?) worm... a far greater hazard to timber vessels than a few barnies.

Jim

It's all about the chemistry and the biology.


re. copper pipe. The toxicity of elements and compounds to mammals and marine life are typically VERY different. Read some MSDS sheets, if nothing else. Drawing analogies to copper pipe and drinking water is simply false, since it assumes there is a relationship to marine toxicity, which there is not. Or rather the toxic limitis are different by 100-1000 times. Apples and hand grenades.


re. copper vs copper salts. What matters is getting copper ions in the water, under the microorganism. Thus, it kind of depends on whether the copper is cathodically protected or not.





As for adding chemicals that have not been tested in this application (pepper, dewormer), that's just silly internet mythology. If you really think it is true, paint some sheets, hang them under your dock, and report back in a year. You'll find it's not that simple.

[a64pilot]

Originally Posted by Steve Bean

Water chemistry determines whether copper leaches into the water in the pipes. I have survived over 20 years in the drinking water business. Some water erodes copper, some leaves a mineral deposit which in some cases can build up enough to reduce flow. I am about to repipe my 40-year- old house because pinhole leaks are occurring. The EPA sets a limit on copper in drinking water. Water suppliers over a certain size are required to treat the water to control leaching.

I used to think copper pipe in a house was permeant.
Until I had to replumb our house with Pex. The copper lasted about 30 years, was installed in mid 70’s and replaced early 2,000’s.
Our water came from limestone aquifer and as such was very basic, which I thought wouldn’t be as bad as acidic water, guess I was wrong.

[fstbttms]

Originally Posted by a64pilot

I’m thinking anything would stay free of growth with an aggressive scrub every 14 days.

You would be wrong.

[fstbttms]

Originally Posted by sand6000

If you want more copper then check the antifouling label for the concentration and go with the one that has the most. Also check with other boats in your are and see what is working best.

Copper content is not always an accurate indicator of anti fouling paint efficacy. New copper processing techniques allow manufactures to produce paints that do more with less. I refer specifically to Pettit Trinidad and Interlux Micron 66. The most effective anti fouling paints (IMHO) available in my state and definitely not the ones with the most copper.

[fstbttms]

Originally Posted by a64pilot

So why is it so many think copper is a Biocide? If it were, do you think making drinking water pipes out of it would be smart?

Copper is both good and bad for living things. At very low concentrations, it is useful. But when the concentration increases, it becomes toxic and interferes with cell metabolism.

Biocidal

Copper is also useful as a biocide. This is something we can use to control pests. For plants, it is most often used to remove fungi that grow on the leaves. It can also be used to destroy bacteria and insects that damage farmers' crops. In France, they use it on vines that produce grapes for wine.

Clean pipes

Copper is used for water pipes and central heating systems (tanks and pipes). This is because it doesn't corrode and its ductility makes it easy to shape and install. It also protects against the growth of unwanted, pathogenic bacteria such as legionella, which thrive in stagnant water storage units.

Copper for life. Biocidal copper.