Coppercoat preparation

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Ric

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I am taking the plunge this haul out, and stripping back to gelcoat in order to paint with copper coat. Grateful for any tips.

Is it worth using a primer? Coppercoat say their product is epoxy based so no need - grateful for any corroboration.

What about the keel (mine is cast iron)? I won't have the opportunity to leave it drying out for months - at best I can strip it back to bright metal. Should I then spray with cold galvanising zinc? Or paint with zinc-rich epoxy? Or both? Any recommendations for a good quality zinc epoxy?
 
an iron keel does not absorb water so no need to dry out for months as opposed to getting rid of salt and surface water.

have a word with coppercoat about surface prep. all I would do is to ensure a clean matt surface as with any epoxy coat. would not go near a primer.
 
Mine is all GRP with an encapsulated keel. It already had a protective epoxy coating so I blasted back to that. My only comment is that it dried slower than suggested in the instructions so coating wet on tacky tended to lift areas of the previous coat, so take your time.

Steel keel needs to be pressure washed several times to get all the salt out/off, but I'd check with Coppercoat whether they recommend a primer coat or maybe fair it and epoxy coat (ME-100 ?) before the Coppercoat.

Rob.
 
Ric said:
I am taking the plunge this haul out, and stripping back to gelcoat in order to paint with copper coat. Grateful for any tips.

Is it worth using a primer? Coppercoat say their product is epoxy based so no need - grateful for any corroboration.

What about the keel (mine is cast iron)? I won't have the opportunity to leave it drying out for months - at best I can strip it back to bright metal. Should I then spray with cold galvanising zinc? Or paint with zinc-rich epoxy? Or both? Any recommendations for a good quality zinc epoxy?
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RTFM then do it again!

Do NOT, under any circumstances, put any single pack paint, or leave any single pack paint, under coppercoat. Primers and zinc paints are (AFAIK all) single pack.

Use epoxy on your keel, the thicker the better. Make sure it's solvent free or leave at least a week before coppercoating.

Coppercoat sell an aluminium rich epoxy called corrotech. It is over 90% solids so nearly solvent free. ME100 is a completely solvent free epoxy. With that you must coppercoat the day after epoxying in order to ensure a chemical bond. Sadly, keels are porous so then is no 100% guarantee of completely preventing rust. (short of soaking in fresh water for 6 months then desiccating for a similar time!)

On the GRP, coppercoat can go straight on and will stay there for probably 20 years. As long as you don't use a primer.

Anyway. RTFM of whatever you buy! They coppercoat video is good, and so are their instructions. Just follow them to the letter and you'll be fine.
 
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wotayottie said:
an iron keel does not absorb water so no need to dry out for months as opposed to getting rid of salt and surface water.

have a word with coppercoat about surface prep. all I would do is to ensure a clean matt surface as with any epoxy coat. would not go near a primer.
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sadly it seems they do. They tend to have imperfections in that end up with salts in. You can blast to bright shiny, immediately epoxy with loads of quality stuff, and still you get return of some of the rust.

We do our best, some are perfect, but there is no way I can guarantee a keel won't re rust.

I had one owner who did a lot of research into this and provided a desalinating fluid to put in our blast water (normally we dry blast keels and wet blast the GRP). It still came back. But as I say some are perfect, but looking perfect and painting thoroughly still isn't a 100% guarantee on iron.
 
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Ric said:
No, there are plenty of two pack zinc epoxies on the market. Seems that if it is recommended to treat the keel with epoxy, then it may as well be a zinc epoxy.
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yep that's fair enough.

The test, once it's on, is to rub it with thinners and see if it stains a white cloth. If it does it's no good. If it really is an epoxy it should be fine.

Take note of solevented - non solvented. If solvented, allow at least a week before coppercoating, if solvent free coppercoat next day.

Best though in my opinion to buy the keel epoxy from AMC, the coppercoat people then compatability is assured.
 
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Elessar said:
yep that's fair enough.

The test, once it's on, is to rub it with thinners and see if it stains a white cloth. If it does it's no good. If it really is an epoxy it should be fine.

Take note of solevented - non solvented. If solvented, allow at least a week before coppercoating, if solvent free coppercoat next day.

Best though in my opinion to buy the keel epoxy from AMC, the coppercoat people then compatability is assured.
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Can you be more specific about the "solvent"? The "Rustbuster" zinc-epoxy product recommended by IanJ99 is described as "iso-cyanite free primer" - is this the same as "solvent free"?
 
Ric said:
Can you be more specific about the "solvent"? The "Rustbuster" zinc-epoxy product recommended by IanJ99 is described as "iso-cyanite free primer" - is this the same as "solvent free"?
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i tend to use acetone as it's agressive. The solvent in CopperCoat is water, so not much point testing with that.

To that end, iso cyanit free is not the same as solvent free. It just means the fumes wont kill you (quickly). Coppercoat for example claims to be VOC free, ie it has no solvents in the traditional sense but does have water.

The clues are %age solids, if thats' listed in the literature. 100% solids = completely solvent free, It also (of course) means the dry film thickness is the same as the wet film thickness. Gelshield epoxy for example is only 45% solids, so you paint on 100 microns of epoxy and there is only 45micron of thickness left once the solvent has evaporated.

All that solvent must evaporate, and so you mustn't seal it in with coppercoat, thus waiting a week if it's solvented.
 
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Elessar said:
sadly it seems they do. They tend to have imperfections in that end up with salts in. You can blast to bright shiny, immediately epoxy with loads of quality stuff, and still you get return of some of the rust.

We do our best, some are perfect, but there is no way I can guarantee a keel won't re rust.

I had one owner who did a lot of research into this and provided a desalinating fluid to put in our blast water (normally we dry blast keels and wet blast the GRP). It still came back. But as I say some are perfect, but looking perfect and painting thoroughly still isn't a 100% guarantee on iron.
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Imperfections and porosity have to be a problem - really that keel is a faulty casting and should have been sent back by the boatbuilder, but its too late now. But surely you remember the experiment in the school chemi labs where you put a steel nail in a test tube full of boiled and therefore air free water to discover that it doesnt rust? Rusting requires heat, iron and water - take any of the three away and no rust. In the case of your imperfect keel you should mostly be able to get rid of the water and certainly in less than the months the OP talked of. But even if you cant, you can make the surface air free with a sufficient coat of epoxy. Thats what they do with steel bridges and steel piles which remain rust free until they either get surface damage or the coating breaks down.

I guess your practical experience reflects the frequency of nasty cheap and imperfect iron keel castings together with the difficulties of small scale application of coatings in a boat yard.
 
I have 2 boats . a hanse 311 & a Squib. I did both boats with the copper coatings last year
I applied AMC coppercoat to the Hanse & it failed miserably. On my round UK trip this year I had to have the boat hauled out in St Hellier & jet washed. the chap doing the jet washing ( Billy Hibbs)said he has never seen a copper antifould work yet.
When i went to LIBS this year to ask for any suggestion as to why it did not work properly AMC were very self righteous & said I should have abraded it before launching. I pointed out it did not say this on the DVD supplied & when I bought the stuff i was told that it did not need abrading every year as with earlier versions. They said well I should have read the instructions. ( so why issue a DVD?). I asked why I was getting streaks on the surface a year after applying & they said I had got rain on it after applying. This is untrue but they would not believe me. I was not impressed with the attitude. I was supposedly lying & in the wrong.
That being said ; I watched my boat being hauled out after the end of my trip & there was a slime which was rather like condensation one gets on a car windscreen so perhaps it has started to work. However, I was in the Caledonian canal for 5 days so that may have had an effect being fresh water. next year will be the test

Re the metal . I used the primer supplied by AMC. but only did 2 coats as the stuff is 2 pack & I had 2 tins so used a tin per coat & wasted a lot. I should have split into 4 & applied 4 coats not 2. I do have one spot of leaching rust

Re the gelcoat. I really wish i had applied some epoxy first as I am not sure that having butchered the gelcoat when sandblasting AMC's assurances that this is OK are worth didly squit

Re the squib. Although I paid for it, my crew bought the copper antifoul & put it on himself. I do not recall the name but it was not AMC.
This boat sits on a mooring all sailing season & the copper was not abraded before launch. We have several coppercoated squibs in our club & when they came out this year all had had a brush wash mid season. ( because we race & owners want the cleanest surface finish) Ours was much better than the Coppercoated squibs, which had all been professionally applied. My crew also helped with my Hanse & he says the squibs copper antifoul was much easier to apply
I suggest forumites at least consider other manufacturers before going with AMC. My crew says the other manufacturer was very helpful. , I believe the squib worked out dearer per M2 than the Hanse. But as I did not have to do any work I was happy to let him get on with it. The results suggest it was worth it
I seem to recall that the squib coating was applied over a couple of days whereas the coppercoat has to be done in 1 day for all 4 coats
 
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What do you mean by failed miserably on the hanse? I don't know billy hibbs but he is talking billy *******s. There are now over 40,000 coppercoated boats and people keep coming back for more, some must have been to st helier.

RTFM. It says to abrade before launch. Anyway, no harm done, if you don't abrade before launch sometimes it's fine, it just takes longer to start the corrosion process. Once it's gone green it's fine for 6-8 years before you need to abrade again.

Remember that it takes 3 months to get to full strength so the first year will always be worst for antofoul performance. More so if you didn't abrade. If it is green it will get better.

If it hasn't gone green, abrade before launch.

Streaks. I presume you mean vertical ish and thin? Yes it did get wet. You may not have known, it could be condensation. But they don't make spripey paint, it got wet.

Dark streaks are fine. They show water after the coppercoat is cured, just slightly differnt rates of corrosion. Does no harm and doesn't effect the performance. Light streaks show it got wet before it was cured and are a problem.

Yes, you should only have mixed as much as you needed. 4 coats would have been a lot better. At £130 a tin I'm amazed you elected to waste half the second tin. So be it. Sand the area around the rust and do a local repair. 3 coats of epoxy then 4 of coppercoat. 2 days will be enough if you use a hairdier to get all the epoxy on on the first day.

Sandblasting can vary. Done well on sound GRP and you don't need to epoxy. People still buy the cheaper dry blast for their boats which is taking more of a risk. We offer wet and dry, the former being £2 more per foot.

Consider other manufacturers by all means. Only one has been doing it for 20 years and has done over 40,000 boats. That's the reason I only ever use coppercoat. I dallied with other manufacturers, all and i mean all failed and have been replaced with coppercoat. The original and the best.
 
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