Copper content of bottom paint

[fstbttms]

Please rest assured I don't make unsupportable statements.

In this case, there are specific analytical procedures (reference below) which were used by the manufacturers required for submittal and certification of their products for sale in the US.
Although not the "book" I was referring to (any analytical chemistry text will do), copper bottom paint was and continues to undergo toxicity and efficacy testing for product development purposes necessitating continual data submission and review and none of the data correlates copper content to either toxicity (a determining factor in efficacy) or prevention of growth.

This is their data; not some testing done by the government.

Buying bottom paint based on copper content is analogous to buying a battery which weighs the most. People do that too but don't insinuate I don't "know what I'm talking about" just because you don't want to believe me.

I was trying to help as do many people here. With responses such as yours, many people might stop bothering.





www.epa.gov/osw/hazard/testmethods/sw846/pdfs/1313.pdf

So your response to our criticism of your position is to provide a link to a 30-page study called, "LIQUID-SOLID PARTITIONING AS A FUNCTION OF EXTRACT pH USING A PARALLEL
BATCH EXTRACTION PROCEDURE", knowing full well that a layman is not going to be able to make heads or tails of it? Not to mention it does not specifically refer to anti fouling paint?

Guess what? Nobody here knows what the hell you are talking about or if you are right or if you are wrong. And since none of us can decipher your response, you have proved nothing, except that you want everybody to think you are the smartest guy in the room.

I have news for you, Mr. Wizard. Copper content is absolutely the easiest way for the non-scientist boater to determine how effective an anti fouling paint product is going to be. And here's a further news bulletin- the heavier the paint can, the more effective the product inside it is likely to be. The bottom line is that copper is the primary biocide in most anti fouling paints and the more of it there is, the better that paint is likely to be at retarding fouling growth. Nothing you have said, or will say can alter that fact.

 

[Johnnie Walker Black]

PS. Typically... Heavier batteries are better too. Is there some conspiracy against common sense on this forum?

I'm getting old and tired here

 

[RichH]

So your response to our criticism of your position is to provide a link to a 30-page study called, "LIQUID-SOLID PARTITIONING AS A FUNCTION OF EXTRACT pH USING A PARALLEL
BATCH EXTRACTION PROCEDURE", knowing full well that a layman is not going to be able to make heads or tails of it? Not to mention it does not specifically refer to anti fouling paint?

Guess what? Nobody here knows what the hell you are talking about or if you are right or if you are wrong. And since none of us can decipher your response, you have proved nothing, except that you want everybody to think you are the smartest guy in the room.

I have news for you, Mr. Wizard. Copper content is absolutely the easiest way for the non-scientist boater to determine how effective an anti fouling paint product is going to be. And here's a further news bulletin- the heavier the paint can, the more effective the product inside it is likely to be. The bottom line is that copper is the primary biocide in most anti fouling paints and the more of it there is, the better that paint is likely to be at retarding fouling growth. Nothing you have said, or will say can alter that fact.

Guess what? Don is essentially 100% correct and in spite of the derision offered by others. Within paint the 'availability' of copper IS dependent on the essential 'blanketing' of the copper by the carrier vehicles used in the paint. For the hard epoxy paints one can easily observe that the copper content in fact does not and is not 'available' until one grinds away or abrades the "build up" many years later. So too with ablatives which hold the micronized copper in the paint matrix until the carrier surface erodes and exposes the copper in a continual ablation (surface erosion) process. So in both cases of 'hard' and 'ablative' paints only when the underlying copper within the carrier matrix becomes exposed to the SURFACE of the painted matrix does it become active as either a direct metallic toxic or sufficiently wetted to release Cupric ions (by electro potential) to stimulate hard growth to not attach. Its all efficiency of 'surface effect' chemistry and definitely NOT dependent on how much copper is within the paint matrix other than to supply new and continual surface effect as the old surface wears or erodes away. Of course, the longevity and efficacy is due to the thickness .... the storage of copper to become active as the surface continually erodes and/or supplies the needed ionic species to retard growth .... and the same is true of solid copper plate and sheets. Its all 'surface chemistry' and the toxicity is dependent on the amount of copper mass that becomes continually available to the SURFACE to provide the necessary 'reaction rate' of toxicity.

Simplistically, the more copper content the more copper will eventually be available to provide the surface effect. In the case of ablatives, add the erosion rate of the carriers (inerts) of how fast the copper becomes active at the SURFACE. Ditto, how efficient the bottom is kept from slimes and other growth which 'blanket' the active copper SURFACE.

 

[fstbttms]

Within paint the 'availability' of copper IS dependent on the essential 'blanketing' of the copper by the carrier vehicles used in the paint. For the hard epoxy paints one can easily observe that the copper content in fact does not and is not 'available' until one grinds away or abrades the "build up" many years later.

Nice try, but no soap. If one were to put a single coat of paint on a boat hull, and let it stay in the water for say, 6 or 8 years, all of the copper biocide in that paint will have leached out. That is the point. It is all available. If one builds up paint thickness to the point where water will no longer penetrate to release unleached copper in the deeper layers (as in your scenario), that is not the same thing as saying that some percentage of the copper is rendered inert, as Don maintains.

 

[Johnnie Walker Black]

Rich

Did you not read where I noted: "all other things being the same" ie. the biocide delivery mechanism or paint chemistry? We're not talking about leech factors or ablative properties exposing fresh biocide at a controlled rate. What we are saying is: delivery mechanism aside, copper conten.....
Oh Christ just forget about it.
Some folks you just can't reach.

 

[Don S/V ILLusion]

Nice try, but no soap. If one were to put a single coat of paint on a boat hull, and let it stay in the water for say, 6 or 8 years, all of the copper biocide in that paint will have leached out. That is the point. It is all available. If one builds up paint thickness to the point where water will no longer penetrate to release unleached copper in the deeper layers (as in your scenario), that is not the same thing as saying that some percentage of the copper is rendered inert, as Don maintains.

The chemistry involved is more complex than you think. I tried to depict the mechanisms for copper leachability in the link I provided which is the standard by which all manufacturers formulate their products. if you try to understand it, you will see the process is complicated by a number of considerations you may not understand without a more thorough review.

This may be one of those situations similar to the time when the Flat World Society disbelieved the concept the world is round. In both cases, it takes a review of the math to see the bigger picture.

Look up copper sulfate on Wiki and you may be surprised to find copper as it is generally used in industry comes in many forms, the most prevalent being cuprous and cupric salts with very different properties.

Bottom paint does not contain pure copper but rather various copper salts, each with its own properties.

It is senseless to debate the mechanisms involved unless you have an elementary understanding of which salts are employed in anti fouling and how thy behave.

 

[Don S/V ILLusion]

Rich

Did you not read where I noted: "all other things being the same" ie. the biocide delivery mechanism or paint chemistry? We're not talking about leech factors or ablative properties exposing fresh biocide at a controlled rate. What we are saying is: delivery mechanism aside, copper conten.....
Oh Christ just forget about it.
Some folks you just can't reach.

I know the feeling

 

[RichH]

Rich

Did you not read where I noted: "all other things being the same" ie. the biocide delivery mechanism or paint chemistry? We're not talking about leech factors or ablative properties exposing fresh biocide at a controlled rate. What we are saying is: delivery mechanism aside, copper conten.....
Oh Christ just forget about it.
Some folks you just can't reach.

Im so sorry, I only have an advanced degree in Physical Chemistry, .... you know, chemical reaction rates and stuff like that.

 

[fstbttms]

It is senseless to debate the mechanisms involved unless you have an elementary understanding of which salts are employed in anti fouling and how thy behave.

No, it's senseless to debate when one party cannot (or will not) provide proof of his claims. You may very well be correct in your assertion that a percentage of the Cuprous Oxide may become inert in in the formulation of anti fouling paint. But the fact that you say it doesn't make it true. You have shown nothing from the paint manufacturers to support your claim and your EPA document is, again, not specific to anti fouling paint and even if it were, it is indecipherable to the average reader.

I guess the easy way out for you is to claim your opponent is simply unable to understand the debate, so therefore you will not participate.

 

[Don S/V ILLusion]

I hope this doesnt sound too condescending but In a difference of opinion between someone experienced in cleaning bottoms and someone with advanced degrees and decades of experience in chemical engineering including oversight of manufacturer's efficacy data, I will leave it to anyone still suffering through this senseless discussion to make his own judgment.

I am no expert but I do rely on what the experts tell me.

 

[Gunni]

Yeah, actually it is very condescending. Fstbtms is not just "someone who cleans bottoms", he is a guy with a wealth of hands-on experience relative to bottom paint manufacturer and regulatory claims / assumptions. He sees what works, and what doesn't in the real world, and as such his opinion means more to me than a lab guy, or someone simulating reality by crunching numbers.

 

[fstbttms]

I hope this doesnt sound too condescending but In a difference of opinion between someone experienced in cleaning bottoms and someone with advanced degrees and decades of experience in chemical engineering including oversight of manufacturer's efficacy data, I will leave it to anyone still suffering through this senseless discussion to make his own judgment.

I am no expert but I do rely on what the experts tell me.

Gosh, thanks for the resume. It's awfully impressive.

I guess we can't expect a straight answer from you, though.

 

[RichH]

You guys are beginning to become totally inane ....
THE solution of any bottom paint is not to get into the micro-chemistry and toxicological reactions of zillions of varying bio-species that cause 'growth', the differences of salinity and the vagaraties of nutrient laden waters, different water temperatures, the velocity of the water, etc. etc. etc. .... as you will be dealing with the impossible prediction of exponential numbers, etc. etc. etc.

Suffice it to say that EVERY mooring etc. situation is a very distinct and independent situation as regards 'bottom growth' ... move 1/4 mile from a location and all the combinations of different growth species, etc. etc. etc. etc. changes and becomes totally different. The bombproof solution is simply SEE when boats are hauled, etc. and SEE what bottom paint is actually the best working bottom paint for the exact and adjacent conditions where you will be moored, etc. and no matter the marketing glitz, and no matter what the 'magazines are hyping', etc. etc. etc.
LOOK, SEE, ask questions, then make a decision based on what historically works best for the actual location, not miles away from where you will moor, etc. .... and then expect the bottom attaching species to change and vary as the water quality, etc. etc. etc. changes, ..... and then do the whole empirical selection process all over again as the 'biology' of the bottom 'attachers' changes.

Simple speak: imitate what those with the least amount of bottom crud are using in YOUR very local area.

 

[Scott B]

This has been a very interesting discussion. I can see both sides of the arguement, but do not know the answer.

However, it is deteriorating into insults flying back and forth, which, if continue will nuke this thread. Please keep the comments civil and not personal attacks.

 

[Don S/V ILLusion]

I agree with what Rich said. Regardless of the issue of copper content advertising, the choice should ultimately be made based on what works best in a specific area, not advertising which can often be misleading. If we go back to the origins of this discussion, that is what we suggested originally.

Everything else is background noise.

 

[fstbttms]

Simple speak: imitate what those with the least amount of bottom crud are using in YOUR very local area.

Regardless of the issue of copper content advertising, the choice should ultimately be made based on what works best in a specific area, not advertising which can often be misleading.

And nobody here ever said anything to the contrary. Just (unsuccessfully) trying to get someone to back up their bold statements, that's all.

BTW- if you read any anti fouling paint advertising or product description, you will be led to believe that the product in the can is the Second Coming, as far as stopping fouling growth goes. Most of us hopefully know better than to take that as gospel. But what does not lie is the copper content listing on the back. More is better and that is a fact. I may only be a lowly hull cleaner, but my 18+ years experience and 20,000+ hulls cleaned have taught me that there is no paint that comes in at 38% Cuprous Oxide that can compete with one that comes in at 60-70%. That is just reality.

 

[tomgrigsby]

So your response to our criticism of your position is to provide a link to a 30-page study called, "LIQUID-SOLID PARTITIONING AS A FUNCTION OF EXTRACT pH USING A PARALLEL
BATCH EXTRACTION PROCEDURE", knowing full well that a layman is not going to be able to make heads or tails of it? Not to mention it does not specifically refer to anti fouling paint?

Guess what? Nobody here knows what the hell you are talking about or if you are right or if you are wrong. And since none of us can decipher your response, you have proved nothing, except that you want everybody to think you are the smartest guy in the room.

I have news for you, Mr. Wizard. Copper content is absolutely the easiest way for the non-scientist boater to determine how effective an anti fouling paint product is going to be. And here's a further news bulletin- the heavier the paint can, the more effective the product inside it is likely to be. The bottom line is that copper is the primary biocide in most anti fouling paints and the more of it there is, the better that paint is likely to be at retarding fouling growth. Nothing you have said, or will say can alter that fact.

FB you have decades of experience underwater seeing what happens that few of us have. Recognizing your experience gives much weight and credibility to your words. I've never seen what you've seen and have to take your word for it. If I dove along side you, it would take years for me to recognize some of the things you recognize in seconds. It would be pointless to drag me through the water for an hour trying to educate me.

Same with these people who reference complex chemistry documents. We don't understand these documents, but it important to note that they do. The information makes perfect sense to them because they've spent years in that arena. We should give weight to their experience with the chemistry and manufacturing processes. They'll never be divers, and you'll never be a chemist, and both sides are more or less in violent agreement!

The discussion, even though it got a little testy, was very helpful to me. Bottom paint is more complex than I realized and environmental factors such as slime can render otherwise superb paints ineffective. Generally, more copper is better, but not always. Makes sense given the price of copper. Generally, price is indicative of quality, but not always. Now lets all hold hands and sing kumbayah!

 

[Sailm8]

You guys. We're cheap ass sailors and buy what's on sale. LOL

 

[Don S/V ILLusion]

And nobody here ever said anything to the contrary.

I hesitate to beat a dead horse (again) but you did, at least twice:


"I'm sorry but copper content is the single biggest indicator of efficacy of a bottom paint."

"Copper content is absolutely the easiest way for the non-scientist boater to determine how effective an anti fouling paint product is going to be."

I think we already agreed the "easiest way..." to tell is to ask other co-located boaters.

If anyone learned anything from this debate, that's great! Others are free to disagree but when you start being argumentative about it, nothing productive results.

I end my participation in this thread by suggesting that people not make expensive bottom paint purchases based only on the advertizing on the can.

 

[fstbttms]

I hesitate to beat a dead horse (again) but you did, at least twice:


"I'm sorry but copper content is the single biggest indicator of efficacy of a bottom paint."

"Copper content is absolutely the easiest way for the non-scientist boater to determine how effective an anti fouling paint product is going to be."

I think we already agreed the "easiest way..." to tell is to ask other co-located boaters.

I also said that if you keep your boat in a low-fouling region, you may not need a high-copper anti fouling paint. But that doesn't mean that just because you can get away away using a low-copper paint that a high-copper paint wouldn't be just as, or more, effective. It absolutely would be. If you can be coerced into posting again, please tell me why that would not be the case.