Piers
Well-known member
Let's assume a new boat is delivered having been epoxied before being anti-fouled. You then anti-foul every year. How often should the hull be cleaned of all anti-foul and new epoxy applied before re-anti-fouling again?
Re-applying Epoxy - how often?
- Thread starter Piers
- Start date
longjohnsilver
Well-known member
Interesting question Piers. I guess for most people the answer would be never. Eos was epoxied from new, unfortunately when we stripped, or rather had her blasted prior to copper coating, we discovered that the hull had not been keyed before the original epoxy was applied and therefore in places was coming away. However the better news was that it had done it's job, and after 25 years the hull was still extremely dry.
So my answer to your question is that if applied properly and with the recommended number of coats, it should last a long, long time. I seem to recall you're having work done on the hull of Play d'Eau, sounds as though you've discovered a problem? If so, hopefully nothing too serious.
Piers
Well-known member
Hi LJS. I'm told that no epoxy manufacturer will guarantee their products for more then 5 years, albeit their products may actually last for ten provided they've been applied correctly. Hence, boats should be checked every 5 years for moisture content, and if necessary, taken back to the epoxy to see its state. If OK, re-epoxied, but if not OK, the old epoxy removed and new applied.
I suspect the industry is still learning, but it also poses the question if manufacturers are advising their customers accordingly.
Elessar
Well-known member
if it aint broke dont fix it piers. Taking epoxy off is a very difficult job. It cannot be taken off with an abrasive blast as it is harder than the gelcoat underneath. Sanding off is a huge job and will, to an extent, damage your boat. Epoxy is waterproof and stays that way. It doesn't spontaneously degrade at the end of a warantee. If it isn't flaking off, leave well alone. If it is flaking off and it is localised, repair that bit.
As for removing the antifoul the average is i reckon every 7 years. If you have a solvented epoxy system it will have had 6 layers of contrasting colours, with a dry film thickness of about 45 microns per coat. After antifoul removal if it is done well, you will be left with a green grey mottle, showing the blast will have removed on average about 45 microns of your 300 or so microns of epoxy. One coat of solvent free over the top before re antifouling would therefore put you back to the thickness you started with. Most people don't bother as 250 microns of epoxy is left after all.
You don't need to remove the antifoul to measure the moisture content of the hull by the way.
IDAMAY
Active member
A very topical point for us Piers. Ocean Star (Trader 42 for readers who don't know us) was launched in 2008 and was epoxied from new. We are having the hull blasted this winter as the anti foul isn't adhering too well now. I am hoping that the epoxy will be in good condition and that all we will have to do is prime and apply two coats of anti foul. As we mostly travel at displacement speed we use Cruiser Uno with reasonably good results. Any thoughts on alternatives?
We are exactly in line with the seven year suggestion above.
Richard.
We are exactly in line with the seven year suggestion above.
Richard.
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Imperial One
Active member
Hi Piers,
An interesting post, hope you are well and all is good with you.
We always epoxied the Atlantic's from new and have never had to redo any of them to my knowledge.
As long as it is applied correctly in the first instance it should be OK to leave well alone.
In short Elessar is bang on the money with his assessment IMHO.
Mike.
An interesting post, hope you are well and all is good with you.
We always epoxied the Atlantic's from new and have never had to redo any of them to my knowledge.
As long as it is applied correctly in the first instance it should be OK to leave well alone.
In short Elessar is bang on the money with his assessment IMHO.
Mike.
benjenbav
Well-known member
Out of interest, if the epoxy can be patch-repaired as mentioned, would it be practical to key the whole hull and re-epoxy over the first treatment? Weight might be a factor with lighter boats but perhaps the difference would be marginal for something like a Fleming 55?
Elessar
Well-known member
the only sensible approach in my view. Taking it off is folly unless there is a jolly good reason which would probably involve removing the gelcoat as well.
longjohnsilver
Well-known member
That's exactly what we did last spring before applying coppercoat. As long as the previous epoxy layer is keyed, ie lightly sanded, I can't see any problems in putting new layers on, as long as the hull is dry.
Elessar
Well-known member
yes key with 80-120 grit.
If the hull isn't dry, it wasn't dry when you put the epoxy on, so stop worrying. If you really want to worry, no point taking the epoxy off because it won't dry through the gelcoat. You have to take the lot off.
npf1
Active member
FWIW, boat was epoxied with a seven coat West system in 1995 and there were no signs of degradation of moisture level increases when surveyed in 2000, 2003, 2008 and 2013. Boat was in water all year for most of those 18 years too.
Piers
Well-known member
When having some GRP work completed on Play d'eau in Southampton last year (2014) I employed a surveyor, Guy Nicholls of Solent Marine Surveys. In chatting, we had some interesting discussions about epoxy treatments.
As far as he's concerned, if a boat has been epoxied and the treatment has been completed properly, it will certainly last the 5 years the epoxy manufacturers state. But after 5 years, the hull's moisture content should be checked (the old anti-foul doesn't need to be removed for this). If there's moisture detected, the reason should be established and the appropriate action taken. Whether it's patch and scratch depends on the findings.
npf1 mentioned the West system. This is generally regarded as the best of the bunch of epoxy treatments, and should last 10 years. But, Guy still advises checking the hull after 5 or so years, just in case. A simple and inexpensive check to ensure the integrity of the epoxy and hull.
I had no idea of any of this, having bought Play d'eau in 2003. Nothing in the manual, nothing in newsletters, and nothing really in the mags, yet maybe I've missed something. I just thought that annual anti-fouling was all that was necessary, and all one did was to apply fresh anti-foul. Thankfully, on checking, Play d'eau's hull was absolutely dry!
But it was a thought provoking matter that's started me thinking. For example, when buying a new boat, does the manufacturer advise about treatments and checking?
As far as he's concerned, if a boat has been epoxied and the treatment has been completed properly, it will certainly last the 5 years the epoxy manufacturers state. But after 5 years, the hull's moisture content should be checked (the old anti-foul doesn't need to be removed for this). If there's moisture detected, the reason should be established and the appropriate action taken. Whether it's patch and scratch depends on the findings.
npf1 mentioned the West system. This is generally regarded as the best of the bunch of epoxy treatments, and should last 10 years. But, Guy still advises checking the hull after 5 or so years, just in case. A simple and inexpensive check to ensure the integrity of the epoxy and hull.
I had no idea of any of this, having bought Play d'eau in 2003. Nothing in the manual, nothing in newsletters, and nothing really in the mags, yet maybe I've missed something. I just thought that annual anti-fouling was all that was necessary, and all one did was to apply fresh anti-foul. Thankfully, on checking, Play d'eau's hull was absolutely dry!
But it was a thought provoking matter that's started me thinking. For example, when buying a new boat, does the manufacturer advise about treatments and checking?
IDAMAY
Active member
But it was a thought provoking matter that's started me thinking. For example, when buying a new boat, does the manufacturer advise about treatments and checking?[/QUOTE]
There is certainly no mention of it in the otherwise quite comprehensive Trader manual for the 42. I am quite pleased you started the thread as it is food for thought.
Richard.
There is certainly no mention of it in the otherwise quite comprehensive Trader manual for the 42. I am quite pleased you started the thread as it is food for thought.
Richard.
Piers
Well-known member
Hi Richard. I must say that the whole area became really intriguing. And it all depends on hull preparation, application, timing and so on. It's a whole science in itself which is still evolving, and not one to be tinkered with.
Really made me think - and made me go to the Fleming Manual in which no mention of hull care was made. But then that was 2003....
Bandit
Well-known member
Most manufacturers view the gel coated hull as the finished product, providing it lasts the warranty period, that is all their worried about.
Abrade, an epoxy tie coat and two coats of Antifouling is an extra ( most manufacturers, dealers don't use an epoxy tie coat)
Abrade seven coats of epoxy and two coats antifouling is most definitely and extra. Epoxy coating a hull like this is an expensive extra in most peoples minds.
Antifouling is rarely scraped off or abrasive blasted off on a boat under 10 years.
Moisture levels are only normally taken on a sale survey or when one suspects a problem.
After 10 years to lift a boat, abrasive blast to remove antifouling, fill any voids, sand any areas requiring it, patch prime then 6 or seven coats of epoxy and two costs of antifouling is viewed as very expensive.
Abrade, an epoxy tie coat and two coats of Antifouling is an extra ( most manufacturers, dealers don't use an epoxy tie coat)
Abrade seven coats of epoxy and two coats antifouling is most definitely and extra. Epoxy coating a hull like this is an expensive extra in most peoples minds.
Antifouling is rarely scraped off or abrasive blasted off on a boat under 10 years.
Moisture levels are only normally taken on a sale survey or when one suspects a problem.
After 10 years to lift a boat, abrasive blast to remove antifouling, fill any voids, sand any areas requiring it, patch prime then 6 or seven coats of epoxy and two costs of antifouling is viewed as very expensive.
Piers
Well-known member
...and that's the problem n a nutshell.
DAW
Active member
My 2005 Sunseeker was inspected by a surveyor at purchase - hull was checked with the boat out of the water and found to be dry and in good condition prior to antifouling by the seller. After two years of ownership, the same surveyor inspected the boat again during its annual maintenance lift - hull was found to be completely dry, but he recommended abrasive blasting to remove years of built-up hard antifoul. After the antifoul was removed, the hull was inspected again and although hull moisture readings were non-existent his recommendation was to refinish the epoxy coating before antifouling. The yard (which has no connection to the surveyor) then applied three coats of epoxy and two coats of self-polishing antifoul - the cost was high but reasonable considering the work involved.
The view of the surveyor was that after 8-10 years of regular use (75-100 engine hours per year) on a largish planing boat, it would have been false economy not to renew the epoxy coatings when the hull was already being blasted clean to remove the years of accumulated antifoul.
The view of the surveyor was that after 8-10 years of regular use (75-100 engine hours per year) on a largish planing boat, it would have been false economy not to renew the epoxy coatings when the hull was already being blasted clean to remove the years of accumulated antifoul.
Greg2
Well-known member
Really interesting stuff. Our boat was, we understand, epoxied from new but I had no idea that it should be checked etc. She is out of the water now so I may check the moisture levels before she goes back in.
rosssavage
Active member
My boat is now 26.
She has never been epoxy coated.
She doesn't have osmosis.
simple really...
She has never been epoxy coated.
She doesn't have osmosis.
simple really...
BoatShow Avenue
New member
Hi Piers, if the epoxy was applied correctly, you should'nt remove it, as has been mentioned in earlier replies, if the job was done properly it should last forever. Epoxy is a non-degradable material, which means it wont loose its properties. But, if you see any spots where it is peeling off then you should consider a professional to look at it and then do the proper reparations.