Bottom paint after 5 years out

[earthbm]

I know the industry people will tell you that the “biocide is gone”. But how is it gone? Evaporated? It’s not a organic agent, despite “bio” in its name. If it’s copper - how is it “gone”?

[fstbttms]

Originally Posted by earthbm

I know the industry people will tell you that the “biocide is gone”. But how is it gone? Evaporated? It’s not a organic agent, despite “bio” in its name. If it’s copper - how is it “gone”?
Attachment 256610

The copper biocide in your anti fouling paint leaches out of the paint 24/7/365, regardless of whether you use a hard or ablative paint and whether the boat moves or not. This is how it retards fouling. If the biocide remained trapped in the paint's matrix, it wouldn't keep fouling growth from attaching. Typically after 2-3+ years the biocide has depleted to point where the paint loses effectiveness.

[Bill O]

Here's an interesting newer paper looking at salinity and effectiveness of copper based bottom paints. https://www.sciencedirect.com/scienc...43135420309180


(if you aren't a science person, just read the abstract to get the overall conclusion)

[fstbttms]

Originally Posted by Bill O

Here's an interesting newer paper looking at salinity and effectiveness of copper based bottom paints.

This study essentially says that the amount of copper in an anti fouling paint is irrelevant and that in freshwater, no anti fouling paint is needed at all. Maybe all that is is true in Sweden (where the study was conducted) but it isn't the case in California, I promise.

[Bill O]

Part of the conclusion of the paper was copper paints did nothing in fresh water to retard fowling. Do you disagree w/this conclusion?

Besides anecdotal information, do you have any scientific papers testing various copper concentrations in paints from California waters? Not trying to make an argument here, just like better research w/facts to reduce some know variability.

For the record, I did think your assessment of hard and ablative paints was spot on in the other recent bottom paint thread.

[fstbttms]

Originally Posted by Bill O

Part of the conclusion of the paper was copper paints did nothing in fresh water to retard fowling. Do you disagree w/this conclusion?

The study says that there was no benefit from the use of anti fouling paint in freshwater. I do not agree that that would be the case in California.

Originally Posted by Bill O

Besides anecdotal information, do you have any scientific papers testing various copper concentrations in paints from California waters? Not trying to make an argument here, just like better research w/facts to reduce some know variability.

The studies done in California that I am familiar with were looking for the specific amount of copper released from anti fouling paints both during passive leaching and in-water hull cleaning activities, not whether any of these products were effective or not or what effect salinity had on their leach rates.

Originally Posted by Bill O

For the record, I did think your assessment of hard and ablative paints was spot on in the other recent bottom paint thread.

Thank you.

[sailorboy1]

Originally Posted by earthbm

I know the industry people will tell you that the “biocide is gone”. But how is it gone? Evaporated? It’s not a organic agent, despite “bio” in its name. If it’s copper - how is it “gone”?
Attachment 256610

It isn't "gone". If there is still "color" there is still copper. The whole mixture is nothing but copper, in copper's case, a binder to hold it and make stick to the boat, and if ablative a polymer that wears down. The copper doesn't "disappear" and leave behind the binder and polymer/copolymer. At least that is what a chemist will tell you as compared to one bottom cleaner.

[fstbttms]

Originally Posted by sailorboy1

It isn't "gone". If there is still "color" there is still copper. The whole mixture is nothing but copper, in copper's case, a binder to hold it and make stick to the boat, and if ablative a polymer that wears down. The copper doesn't "disappear" and leave behind the binder and polymer/copolymer. At least that is what a chemist will tell you as compared to one bottom cleaner.

So your point is that if there is still paint on the hull, it's still doing its job? If this is what you believe then you clearly don't understand how anti fouling paint works.

Originally Posted by sailorboy1

The copper doesn't "disappear" and leave behind the binder and polymer/copolymer.

This is EXACTLY what it does. Water penetrates the paint surface thereby allowing the copper biocide to leach out and into the boundary layer just outside the coating surface. This is precisely why copper in our waterways is an issue today.

The terms "leach rate" and "copper loading" exist for a reason.

[AKA-None]

Originally Posted by fstbttms

This study essentially says that the amount of copper in an anti fouling paint is irrelevant and that in freshwater, no anti fouling paint is needed at all. Maybe all that is is true in Sweden (where the study was conducted) but it isn't the case in California, I promise.

Hmmm if I didn’t put something on my boat in freshwater then I’d have a bunch of zebra mussels if nothing else. Eg not counting the weed growth

[earthbm]

I guess I wasn’t clear in the subject. The boat has been out of the water, on land, for 5 years.

[fstbttms]

Originally Posted by earthbm

I guess I wasn’t clear in the subject. The boat has been out of the water, on land, for 5 years.

OMG

[gamayun]

Originally Posted by earthbm

I guess I wasn’t clear in the subject. The boat has been out of the water, on land, for 5 years.

Good one, earthbm

0_o

[Don C L]

Ok, I gotta say, I am in California and I last did the bottom paint in 2014! And my boat's always in the water! Really! I don't have it cleaned regularly, occasionally I do it myself, but the last time it was cleaned the diver said it wasn't too bad. (BUT, I am in a section of Channel Islands harbor that gets a good deal of fresh water.)I can't even remember the brand now, I think it was Petit. I keep thinking the bottom is just going to explode with life, but not yet. Any day now probably. I'm just really lucky.

[Boatyarddog]

Originally Posted by earthbm

I know the industry people will tell you that the “biocide is gone”. But how is it gone? Evaporated? It’s not a organic agent, despite “bio” in its name. If it’s copper - how is it “gone”?
Attachment 256610

Here in PNW, I have friends that just "reactivate the coating" by scratching up the coating with a scotch brite pad, works for them.

Bottom paint, ablative types, when exposed to air get a "patina" that seals the surface, sometimes seen as green, or brown.
This is my Opinion, and have heard it more than once.
Not going to respond to posts as its not an arguement, as its just a possibility, it works.
Boatyarddog

[earthbm]

Originally Posted by gamayun

Good one, earthbm

0_o

Originally Posted by fstbttms

OMG

Any professional wisdom to share?