Coppercoat Antifouling On Test
Well, almost a year has passed since we slipped the boat and slapped on a coat of copper antifouling. So, it’s time we let you know how things are doing down there, under the water.
To recap: Before we built Mollymawk we used to own a GRP yacht, and a year or so before we sold her she was painted with Copperbot, the original copper-impregnated epoxy antifouling. This type of antifouling is said to be less damaging to the environment than any of the metal-leaching kinds, but it was a very new thing at that time and we knew that we were taking a gamble.
Happily, the gamble paid off; that copper paint was fantastic. The boat once spent three months in a French marina renown for its fouling, and while the other yachts all acquired lush gardens and pet eco-systems on their undersides, our boat stayed absolutely and perfectly clean!
Unfortunately, that paint was also very expensive, and when we came to launch the new boat we simply couldn’t afford to give her the same treatment. So we mixed our own antifouling, using two kilograms of copper dust to one litre of epoxy (which is the legal, environmentally safe maximum).
That home-brewed copper-impregnated epoxy worked, after a fashion, but nowhere near so well as the real thing. Thus it was that, eight years on, we decided to make the necessary investment. By this time the founder of the Copperbot company had died, but his formula had been bought by the main sales agents, Aquarius Marine. Aquarius are now producing the same paint but under a slightly different name – Coppercoat – and thus it was that we came to be slapping on genuine Coppercoat antifouling.
Actually “slapping on” is not the right terminology for the long and elaborate process of painting a boat with Coppercoat. Other, more conventional antifoulings can be applied over pretty much any other muck – having bought the paint one simply opens the tin and starts daubing – but the application of Coppercoat is such a fine art that the manufacturers even supply an explanatory DVD. We watched it, and then we followed the instructions to the letter.
First we spent a week preparing the hull, removing every last vestige of barnacle shell from our previous coat of home-brewed copper antifouling. Then we mixed the epoxy and stirred in the appropriate quantity of copper powder, using an electric drill as a whisk. After that we applied the necessary coats, at the appropriate time intervals, four of us working at this task while the fifth member of the crew was permanently employed in stirring the paint. Then we waited, with one eye on the sky – because the new paint had to be kept absolutely dry for the requisite interval. Then, finally, just before Mollymawk went back in the water, we burnished the hull, thereby exposing the copper.
What a performance!
While we were working on the boat various other yotties came to watch. “Why are you going to all this trouble?” they wanted to know.
We explained that Coppercoat is (allegedly, at any rate) far less damaging to the environment than conventional antifoulings. It appears to have the approval of the UK Environment Agency, who applied it, ten years ago, to a 10m RIB. According to their spokesman: “It doesn’t harm the marine life but just stops adhesion of growth.”
Moreover, although it costs more than twice as much as conventional antifouls our efforts would pay for themselves in the long run. The usual paints leach toxins into the environment and so are gradually used up.
“If you’re still using that old-fashioned poison,” we said, “then you’ll have to slip your boat again in a year or two. But our copper bottom will last far longer. With any luck, we won’t have to slip again for another ten years!”
Indeed, the manufacturers call Coppercoat “10+ year anti-fouling”
Copper-impregnated paint is coppery-pink when it goes on, but within two or three days of her launch Mollymawk’s antifouling had taken on a dark green hue – and so we knew that the metal had, indeed, been successfully exposed to the elements.
We sat back. It had been a gruelling fortnight, and the extra expense had been burdensome too, but we knew that it was all worthwhile.
Nine months later – well, to say that we were disappointed would be a grave understatement.
Our new Coppercoat antifouling is being tested alongside a strip of Hempel’s antifoul, a strip of our old home-brewed copper-epoxy paint, and a band of household emulsion paint which was saturated with hot chilli powder. These other paints (and a couple of combinations of these paints) were applied late last summer to our self-steering rudder.
The first photo shows the rudder as it was when first painted, last September.
From left to right we have, firstly, our own copper-epoxy mix with a dash of chilli powder added. Then we have the same copper-epoxy on its own. In the middle of the rudder we have a broad band of white household paint saturated with chilli powder. Then we come to the Hempels antifouling, and finally to Hempels with a touch of chilli (on the trim tab).
The second photo shows the rudder six weeks later, when the boat was out of the water. As you can see, the chilli-pepper paint is already becoming degraded.
When we slipped the boat we applied the new Coppercoat not only to the hull but also to the upper part of the self-steering rudder, above the other paints, and to the frame which supports the rudder.
The third photo shows the results, eight months later.
At this stage the Hempels and the Hempels-plus-chilli seem to be performing best, but there is plenty of fouling even on those stripes. The household paint with the chilli pepper is now home to several barnacles and a weird red thing. Our home-made copper epoxy and the Coppercoat are both equally coated in slime and tufts of weed.
The fourth photo shows the rudder nine months after the Coppercoat was applied (and a year after the other paints).
The household paint with the chilli pepper has clearly failed the test. What a pity that we didn’t think to include a stripe of unadulterated household paint, so that we could see whether the chilli had any effect at all.
Meanwhile, the Hempels antifoul is also faring rather badly. Its antifouling properties have been exhausted.
The weeds growing on the Coppercoat have become a little more luxuriant.
But the home-brewed copper-epoxy actually seems to have shed some of that slime, and both the plain stuff and the stripe with the chilli pepper are doing reasonably well. They are not doing as well as we would have hoped – certainly, they are not doing as well as the original Copperbot which we applied, all those years ago, to our GRP boat – but they are doing rather better than the competition.
The following photographs show various other areas of the hull eight months after the Coppercoat was applied.
Note that the fouling, here in the Canaries, is very far from being the worst that we have ever seen. Indeed, it is nothing compared to the fouling in the Mediterranean.
In conclusion, the expensive Coppercoat paint is performing notably less well than our previous, cheap and cheerful home-brewed copper-epoxy antifouling!
So much for 10+ years! Our Coppercoat did not even serve its purpose for 10 months!
But why is this so? It works for some other people – it worked for us when we used it on our previous boat – so why do we now find ourselves having to dive on the hull every month and scrape the waterline on a weekly basis?
Before posting this report we sent it to the folks at Coppercoat, asking for their comments. In return we received a lengthy reply which includes the following especially pertinent remarks:
“It would be standard practice (and advisable) to clean a Coppercoat treated boat once a season, but as you might expect, some people clean their boats more regularly than this while others do it less frequently.”
“We know of owners who rarely need to clean their hulls – and I heard from one owner who did not touch the bottom of his boat for five years! However, at the other end of the scale I know of a client in the Caribbean that dives under his boat and cleans the hull approximately three times a year.”
To our way of thinking, if you have to dive on your boat and clean it three times a year, then the antifoul, by definition, is not working. We did not have to dive on our ultra-cheap home-brewed copper-epoxy and clean the boat until she had been in the water for three years.
“While Coppercoat offers a strong degree of protection against most fouling in most locations for many years – it is not described as a “maintenance-free” product and periodic cleaning of the hull should be expected.”
“Please remember that unlike conventional anti-foul (that starts off at full strength and becomes weaker by the day), Coppercoat is actually quite a mild anti-foul when new. Coppercoat increases in potency as the months and years pass. This is because it takes some time for the epoxy to begin to break down and allow the formation and release of its powerful anti-fouling agent cuprous oxide. Consequently it is usual for Coppercoat to perform better in its second year and beyond, than it does in its first year. It is likely therefore that you will see a further improvement in the performance of the coating in the coming years.”
The trouble is, we will not see an improvement of this kind unless we can keep the hull clean. Once the barnacles and the white stuff have settled removing them is very difficult, even with a metal scraper. They invariably leave a little mark behind, and new arrivals subsequently find it very easy to attach themselves to these unprotected areas.
“I suspect that the performance of the Coppercoat will improve while the performance of all the others (ie. the Hempels, the home-brew, and the chilli) will deteriorate. Consequently when you update this report next year, and the year after (and so on), the performance and value given by the Coppercoat will be in stark contrast to the other coatings.”
Well, we sincerely hope that this is true… but we have our doubts.
Coincidentally, a friend who painted his catamaran with Copperbot some ten years ago also had a very good experience of that product and has also just repainted the boat using Coppercoat. He is having much the same sort of experience as us, with quite large barnacles already appearing on his hulls after only one month afloat.
If you have used Copper-impregnated epoxy antifouling on your boat we would like to hear from you. Please use the comments box (below) or drop us a line using the contact form.
Besides telling us which particular brand of copper-epoxy antifouling you used and whether the paint worked for you, please let us know where your boat is moored, or where you have been cruising.
For our next antifouling test we hope to be able to review ePaint – a type which leaches hydrogen peroxide into the water. Whilst it isn’t reckoned to be long-lasting, this particular paint is said to be completely sound from an environmental point of view; and if we can find a paint which does no harm but which keeps our hull clean then we will have succeeded in our objective.
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Thank you very much for taking the time and trouble to publish this very helpful review. Much appreciated. I think I’ll try your home-made solution, but using household gloss paint (or two part varnish/paint) and perhaps less that the 2kg/lt? Burnishing, sounds good, to expose the active ingredient! Thanks again.
Hi Allan, thanks for commenting.
The idea of using ordinary paint or two part varnish sounds interesting, but we’re not sure that it would work.
Firstly, it may not be durable enough. Epoxy, such as we used, is very hard. If you use something less durable it will obviously need redoing sooner.
Secondly, you might find that the copper doesn’t stay in suspension in the paint in the same way. When we did our test with chilli powder in ordinary paint, the chilli sank into the paint, away from the surface.
Thirdly, the epoxy electrically isolates each copper particle, protecting against electrolysis. The paint would be likely to be less viscous, and so would be less inclined to do this.
Why do you want to use paint/varnish rather than epoxy, anyway? Just to reduce the price? I can’t think of any other reasons not to use epoxy…
If you do use epoxy, note that the Coppercoat epoxy is a special “water-miscible” one. In theory, this means that the water can penetrate the epoxy and thus helps to expose the copper. In practice, however, our home-brew worked better despite using ordinary non-water-miscible epoxy.
A final note – if you do use less copper, your antifouling will be less effective and last less long. In the long run, you’ll probably find it’s more expensive. (But you mustn’t use more, because more is damaging to the environment, and is therefore illegal.)
Anyway, good luck with your home-brew – and please let us know how you get on!
Hi guys.
I went a bit further with the copper and had great success. Eg i copper plated the bottom plus mixed copper powder in with reason for through hull fittings and a cast iron keel left the prop alone nothing stick’s to a prop.
I am in the habit off jumping in after anchoring to check my hook, So when in the water a qwik dust of and check of the bottom is in order 10/15 minutes, Anything on it comes right of,(cut off jeans are the rag of choice. I understand its good for 40 years, Cost about $7,000 took 7 weeks to complete.
I am working on a how to manual and slide show for an e book right now. E mail me and i will send you a photo, Royal star is a Yokahama Yawl 1959 sailed 5/6,000 miles.No prob presently in New Orleans USA. The Canaries you must be heading to St Lucia don that crossing 7 times only once single handed.
Sorry for not replying sooner.
You say you “copper plated the bottom” – how? Did you attach copper plates to the entire surface, as they used to do on the old sailing ships? If so, how did you attach them? If your boat is wooden you could nail them, but for a steel boat it would be difficult to attach them.
Hello,
very interesting. Reading this it seems that they have changed the formulation. There is a new product launched, which is also a hard antifouling based on pure copper but needs only 1 coating and is easy to apply. http://www.verometalmarine.com We like the idea to have only 1 coating for many years, thus not polluting the environment with all that antifouling paints. Up to now only good experience about it. So we will try it.
Thanks for pointing out that product. Interestingly, they use polyester rather than epoxy. Since polyester is harder and less flexible, it is more liable to crack or chip, so it would seem likely to last less long.
Let us know how well it works for you!
Hi there,
I am very interested in your comments on Coppercoat – not least because we were at the London boat show yesterday and visited them there. We are leaving this coming summer to cruise on out yacht and like you,dont really want the huge expense of coppercoat but similarly would like a long term coating before we leave.
One option I would like to try is the homemade version you mixed and used, and wonder if you would let me know the ingredients, type of copper powder etc.
Though I’m sure its still quite costly this way, it must be cheaper that the £1750 we have been quoted for the materials from coppercoat !!!
I dont mind occasional scrubbing in the water if its not perfect !
Looking forward to hearing from you,
Kindest regards,
Adrian and Vicky
SV Wild Alliance
Sorry for not replying sooner. We thought we had the details of the type of epoxy and copper we used somewhere, but have been unable to find it.
The quantities are stated above; namely two kilograms of copper dust per litre of epoxy.
Note that whereas Coppercoat uses a water-miscible epoxy, we used a standard epoxy which does not have the same properties of allowing the water to pass through the epoxy to the copper. It is therefore of the utmost importance to sand the surface well to expose the copper.
Hi Mollymawk
I’ve been thinking of using Coppercoat over here. You’re right in that it’s very expensive. I also considered using West Epoxy and copper powder.
I still haven’t come to a conclusion, but it seems that I’ll have to be prepared to scrub the Coppercoat every couple of weeks to remove the barnacle feet. This shouldn’t be too onerous in the warmer waters.
The benefits for me would be the reduced haulout (at 23′ beam it is difficult to find reasonable haulout facilities), and a hard surface to scub back to (an ablative coating doesn’t last long at the waterline when scrubbing the boot-top).
Your experiences are somewhat worrying though, and conflicting with others I have read. What was your own recipe?
We used two kilograms of copper dust to one litre of epoxy. This is the legal, environmentally safe maximum.
Thanks for your reply ….. but what brand of epoxy did you use?
thanks
Sorry for not replying sooner. We thought we had the details of the type of epoxy we used somewhere, but have been unable to find it. If we come across it, I’ll let you know.
Note that whereas Coppercoat uses a water-miscible epoxy, we used a standard epoxy which does not have the same properties of allowing the water to pass through the epoxy to the copper. It is therefore of the utmost importance to sand the surface well to expose the copper.
Well done Mollymawk and crew!
For years I have read the marketing blather published by various antifouling manufacturers and none of them have succedded in their attempts to present their so-called research as clearly as you have done here with your simple and effective test. I’m beggining to suspect that they’re trying to swindle us
While I’ve never used Coppercoat myself, I have been considering it. Searching for information on Coppercoat is how I stumbled upon your test data. I’ve used Petit in the past on my old boats, but now that I’ve built a new boat I’d like to give her something a bit more durable.
Your home brew sounds like the solution. I’m wondering though, did you use a standard bisphenol resin? And, how did you determine the purity of the copper powder that you used? Or, do you think that is even important?
I glassed my ply hulls with West System, and I’m really liking the simplicity of just adding a few more coats of copper impregnated epoxy as the final step. Thanks for the good ideas and proof of concept!
Cheers,
Tom
Sorry for not replying sooner. We thought we had the details of the type of epoxy we used somewhere, but have been unable to find it. If we come across it, I’ll let you know…
What I do know is that we didn’t use the water-miscible epoxy used by Coppercoat, since we couldn’t get hold of it.
I don’t think the type of epoxy is important, so long as you sand the surface to expose the copper particles.
Very interesting report, thanks Mollyhawk.
I treated my boat with Coppercoat in 2008 and it was in the water for 13 months, during which time I didn’t check under the waterline once (I didn’t think it’d be necessary!).
When hauled up after 13 months, there was very little growth of weed, but there was an enormous amount of barnacle infestation (pictures http://nz.dk/CoppercoatBarnacles.html ). Other boats hauled up in the local marina after 6-7 months usually have no barnacle growth with other anti-foulings.
As you can also see from the pictures, the oxidation of the Coppercoat under the waterline was negligible – I believe it’s the oxidation that creates the toxicity to inhibit growth.
I received exactly the same comments from Coppercoat when I contacted them for comments (i.e. standard answer!). I will burnish the surface as recommended and see if that helps this season.
Perhaps there has been a change in formula since Copperbot and the anti-barnacle effect is less.
Thanks for letting us know about your poor experience with Coppercoat.
As you say, the product works by oxidisation of the copper, and if the cuprous oxide isn’t produced it won’t work. And whilst burnishing will clearly help to a certain extent in exposing the copper to the seawater, Coppercoat specifically state that it isn’t strictly required due to the water-miscible epoxy which they use.
That said, we did burnish ours, and it still didn’t work.
It’ interesting also to find evidence that Coppercoat’s replies were merely standard cut-and-paste answers. I had suspected as much, but we had no way of telling before.
hi when you say copperdust what do you mean and where is it likely to be bought, thanks, dave
Hi, Have been reseaching like all the others into coppercote and this seems to be the most imformative to date. Some questions. Was thinking of bringing the waterline up to include a bootstrap? AS expoxy breaks down in UV, would the expoxy breakdown above the waterline. Also read somewhere that someone used expoxy paint and not straight epxoy as the medium? What size granuals of copper or dust would you suggest?
sorry, me again. How far would you guess 1 litre of expoxy + 2 kg copper would cover (sq meters). Coppercote suggest 4 coat, how many coats of your reciept would you suggest? cheers Ian
It is true that epoxy degrades over time when exposed to UV light. However, our antifoul does extend a little above the water and we haven’t had any problems with the paint breaking down with any of the copper/epoxy variants we’ve used.
I wouldn’t recommend using epoxy paint instead of straight epoxy. I don’t see why it would be any less effective as an antifouling, but paint is far less durable than epoxy and so it would be liable to get damaged quicker than a hard epoxy coating.
I don’t know offhand what size copper granules we used or what size Coppercoat use. We might have the information somewhere – if we can find it I’ll let you know.
We applied our homebrew in much the same manner as Coppercoat – several thin coats. I don’t recall the exact coverage but will try to find out.
Hi there
Am also about to mix my own home brew based on info obtained from locals at False Bay Yacht Club in Simonstown, but have stumbled across one problem, the particle size. Ths supplier of the copper dust has a whole range of sizes, but the guys at the club cannot remember what size they used (very sucessfully I might add). If you could recall it would help a lot. Thanks.
Hi Ian,
We don’t have the info about the copper dust we used to hand, I’m afraid.
What I do know is that the dust was very fine, as is the coppercoat copper powder – it feels like talcum powder and makes a slight squeaking sound when you rub a pinch of the dust between your fingers.
I’ll let you know if we find more info.
First off let me say that if I had a grand to blow i would coppercoat immediately. I’d but the materials from the company without hesitation or reserve. My boat currently drysails spending most of the year sitting in the sun in Greece. Coppercoat has got to be just about the ultimate for this type of application. traditional anti-fouls just won’t survive this type of treatment.
That having been said I am trialling my own ‘home mix’ coppercoat.
Copper – I initially sourced two types of copper ‘powder’ after much research. both are very high purity ‘pure copper’ > 99% pure. One was – Copper powder – dendritic – Irregular Spherical. The other is Copper powered – coarse grade fine. The spherical powder is somewhat similar to microballoons or glass spheres used as a filler material. the initial packet I got is still pright copper coloured 6 months after I bought it, clearly not degrading at all, even in my garage. the other is talcum like, dull flat coloured copper. Subsequent comparison with ‘genuine’ coppercoat copper have proved it to be to all intents and purposes the same stuff. ( I subsequently supplied a sample of each to a metallurgist and he agreed ) the company that supplied the material was i think Ronald Britton http://www.colorlord.com/ronaldbritton. iirc I was quoted £220 for 25kg. ( I’ll need about 20 kg for the bottom of Cariad ) I spoke to two companies that could supply in the UK so supply appears to not be a problem.
On to the epoxy. I had a lot of dealing with a most engaging and interesting young lady who is the chief industrial chemist at a company in Uckfield, East Sussex ( I won’t mention the name otherwise she may be flooded with more plees for help
) She was very helpful about explaining the nature of epoxy resins, examining a sample of coppercoat resin and supplying a few sample batches at no charge.
The final conclusion was that there was not much in it and that any suitable matrix for the suspension of the copper would do with allowances made for the continuous immersion in seawater. The critical thing appeared to be the initial exposure of raw copper to the atmosphere / water.
So as I type I have a test panel immersed off a finger jetty in Brighton marina. On one side there is a coating of ‘genuine’ coppercoat resin and my sourced copper powder. On the other my copper powder and stock standard west epoxy. The coppercoat side needed ( nor would it support ) much abrading, its adhesion was low but I gently exposed some copper. The west side was plainly more tough and needed a light sanding to expose copper. ( I must get a loupe or microsope to examine it a bit further ) I exposed copper across only 1/2 of the panel to see if copper was exposed straight after application.
The panel has been in a week. Lets see what happens!
Hi Ian, How did the test turn out? I’m just about to try some home brew on my cat (amaran)! thanks, John….. Lewes resident
just to add to my last comment. a 6kg pack of West Epoxy comes in at around £120 so two of those an the total cost of materials would be around £500. A saving of ABOUT 50% on coppercoat but does it represent peace of mind?
It is a couple of years since you wrote this article, just wanting an update. Has Coppercoats promise of improvement over time shown any validity?
We’ll be publishing another update soon, but in the meantime:
No, I wouldn’t say the performance has improved. We dried the boat out a couple of months ago, in Itaparica, to clean everything off and fix some damaged paint – and already, there is a considerable amount of growth; we have had to dive and clean the boat twice since then. That said, the fowling around here seems to be unusually bad.
One interesting point, however, is that whilst the boat was dried out we re-abraded a couple of areas really well, using steel wool, and those areas have had hardly any growth. So if we could do that to the whole boat, it would certainly be an improvement – but it’s a lot of work, and we’d have to dry our for at least 5 tides… so we haven’t had the chance yet.