Complete a/f removal: WHEN?

[MapisM]

After deciding to postpone te transfer of the new to us boat, I am going to lift and store her for the winter.
Btw, before anyone suggests that, nope, enjoying her also during the winter is not much of an attraction for us, because we already know the area pretty well, and winter weather in the N Adriatic can be worse than in the CdA - let alone the much more southern latitudes we are by now used to.

So, this made me wonder if I shouldn't take the opportunity to have the hull sanded for removing completely the old a/f - something which was never done before in the 13 years of the boat life.
Actually, thickness and roughness of old a/f layers is still acceptable, sort of.
But I don't think that a complete removal can be postponed by more than one or two seasons - hence my doubt about whether to bite the bullet now and go for it while the boat will be on the hard.

So, over to you folks: for how many years is it acceptable in your experience to keep putting new a/f over the old one?

Ref. the method for removal, I'm aware that sanding is not the only one, but it's by far the most popular around here..
And I was confirmed by several folks who made the job that the specialized company who does it is very accurate in bringing the hull back to bare gelcoat, without actually ruining it.
Otoh, everybody is telling me that after a dozen of more of years under a/f layers, gelcoat becomes porous no matter how careful the a/f removal is.
Therefore, it's very common practice to make an epoxy treatment while the hull is stripped to bare gelcoat, as a sort of insurance for the future, also on hulls that show no signs of osmosis.

Your views also on this matter would be highly appreciated.

As an aside, i'm also wondering if it would make sense to take the opportunity to go for some non-traditional a/f, like coppercoat or some foul release products.

Again, all views and experiences welcome.

Even more so if anyone can recommend specific products, and give also ballpark costs of these three jobs (old a/f removal, epoxy treatment, new "non-traditional" a/f).
I'm not asking about traditional a/f because I believe that we all know everything there is to know about it...
Fwiw, 2k Eur give or take seems to be the normal price for 2 layers on a 17m boat, around here.

Thanks in advance!

 

[Hurricane]

Some yards suggest sandblasting.
Personally, I would avoid that.
We had to remove some bad af so we used a slurry (wet) process that was so gentle that it didn't even scratch the plastic trim tab fittings.
So, I would recomend slurry blasting.

As far as teeatment goes, we applied Coppercoat which is epoxy itself so you can skip the epoxy layer after the removal of the old af.

Our Coppercoat cost about 5500 euros inc stripping but that was done at the same time as 3 orher boats. IIRC We are 110 sqm

Coppercoat isn't as good as af against fouling but it is really easy to maintain. Can last 10 years but ours might need recoating after about 8 years. That said, your cruising groungs aren't as aggressive as ours.
All that said, I recommend Coppercoat

 

[MapisM]

Thanks M, actually I said sandblasting but I'm not sure about whether that specialized contractor uses a wet or dry process - I will ask.
But I've seen them working on another boat on the hard some months ago, and they encapsulated the whole hull with plastic sheets, with huge aspirator fans connected to the insulated chamber created under the boat.
The couple of workers inside it were completely protected, with full mask and tanks for breathing.
So, at a guess I would think it was a dry process...
How was yours done exactly?
And did I understand correctly that you had coppercoat applied directly on the bare hull, without any epoxy resin layers in between?
Btw, how old was JW when you went that route?
Thanks again!

 

[Tranona]

There is no specific time. Do it when the build up starts to affect the smoothness of the coating. If you use hard antifoul this can build up fairly quickly, but eroding types by definition take longer to build up as most of each year's paint erodes away.

You will find advocates for all methods of blasting (all better than sanding) and much is down to the skill of the operator. Dry blasting is arguably more common in the UK and it perfectly satisfactory if done by somebody who knows what medium to use in a particular situation. You need to clearly specify what finish you require as, for example if you already have epoxy coating you will want a lighter blast than if you are going back to gel coat in order to apply epoxy.

Blasting is messy so the contractor must agree with the yard on their procedure for protecting the environment and removing the waste. The big benefit is that you get a consistent finish and it is very quick. Some contractors here will also do the recoating after blasting.

 

[Hurricane]

Thanks M, actually I said sandblasting but I'm not sure about whether that specialized contractor uses a wet or dry process - I will ask.
But I've seen them working on another boat on the hard some months ago, and they encapsulated the whole hull with plastic sheets, with huge aspirator fans connected to the insulated chamber created under the boat.
The couple of workers inside it were completely protected, with full mask and tanks for breathing.
So, at a guess I would think it was a dry process...
How was yours done exactly?
And did I understand correctly that you had coppercoat applied directly on the bare hull, without any epoxy resin layers in between?
Btw, how old was JW when you went that route?
Thanks again!

JW was about 2 seasons old when we did the job.
The wet slurry process was so good that there was (literally) no damage to the gel coat.
I have seen boats after sandblasting - and IMO, it isn't worth the risk.

Have a look and re-read of this old thread.
This link will take you to a new post that I've added to the end - a copy of the first post but with the Photobucket links patched.
(Message to the mods - it would be much easier if we were allowed to change our old posts)

You can see from this thread, the condition of the hull after the slurry blasting.

http://www.ybw.com/forums/showthrea...96-The-Complete-Process&p=6197458#post6197458

 

[Portofino]

What you hoping to achieve ?
I,ve seen diy ers sanding rough AF in the yard ,whole families at it. Then applying trad AF
I,ve seen soda blasting by mobile techs back to as new ,€ 40 sq M .Guy reckons it's pretty harmless on the gel coat .

I used for a couple of seasons some trad with PTFE in it was alleging to give a smoother less friction finish .
it did you could feel it ,no special prep just rollered on top of old .Gave an extra 1 to 1-1/2 knots in my sunseeker .
3 cans @ less than € 200 each so 5-600 € tops will cover your boat ,we use 2x cans and have spare to redo the WL .

By mid season or sooner it's the stern gear fouling that knackers planning boat performance ,not the hull
Having the worlds most shiny hull ( Easter lift out ) by July and rough stern gear ---- burn more fuel or go slow either way that's the important bit ,completely overshadows any perceived hull benifit of a back to new .

So I would invest in some dive gear and try a season or two trying to keep the stern gear clean .

Just my 0.02 worth .

 

[MapisM]

What you hoping to achieve ?

Ermm.... Nothing at all, I'd be tempted to answer.
I'm just considering the alternatives, and I thought to ask for other experiences.
Fwiw, my old lady is happily cruising with 20 years worth of a/f on her bottom, but I never saw that as a big deal, because it would take tons of crusts to affect her performance - and even then, the difference would probably be something like an increase in engines load from 30 to 30.2%, if that...
But as you know, P boats are a very different kettle of fish.

 

[Hurricane]

P boats are a very different kettle of fish.

No - quoting YOU
A Fishing boat is a "kettle of fish"

 

[petem]

My 2003 boat had A/F stripped two years ago. I recall from JtB's refurb thread that he had his done too (at 9 years?).

 

[MapisM]

No - quoting YOU
A Fishing boat is a "kettle of fish"

 

[MapisM]

My 2003 boat had A/F stripped two years ago. I recall from JtB's refurb thread that he had his done too (at 9 years?).

Thanks P, sounds like my idea of doing it on a 2004 boat ain't so silly, all considered.
Any idea about the method used, both in yours and JtB's boat?

 

[rafiki_]

Going to strip off the old a/f on Rafiki and copper coat this winter.

 

[MapisM]

Going to strip off the old a/f on Rafiki and copper coat this winter.

P, how old is Rafiki, and what stripping method are you going to use?
I assume it's the first time you bring her back to bare gelcoat, and you used normal a/f in the past, right?
Tx

 

[Divemaster1]

As the (professional) guy that helped me strip the gelcoat off Navigator said ... "osmosis is inevitable on GRP hulls ... all you can do is to try and minimise the moisure the hull absorbs through the gelcoat which gradually increase the longer the hull is afloat. "

If you have the time (having been too late doing it myself), I would strip back AF and do a preventative job as it gives you peace of mind..

 

[sarabande]

If a raggie could stick an oar in...

Multiple layers of AF are likely to be of different types and compositions. 'Exhausted' layers could diminish the effectiveness, or interact negatively with any newer top layer, so the strategic value of a complete AF removal, then application of a barrier epoxy layer prior to a long-term AF would seem to be of good value and merit.

 

[rafiki_]

P, how old is Rafiki, and what stripping method are you going to use?
I assume it's the first time you bring her back to bare gelcoat, and you used normal a/f in the past, right?
Tx

Rafiki is a 2002 boat. I have owned her 4 years. I have used leeching a/f. It will all come off. Not sure whether to blast or scrape yet, will sort in the next couple of weeks.

 

[Elessar]

After deciding to postpone te transfer of the new to us boat, I am going to lift and store her for the winter.
Btw, before anyone suggests that, nope, enjoying her also during the winter is not much of an attraction for us, because we already know the area pretty well, and winter weather in the N Adriatic can be worse than in the CdA - let alone the much more southern latitudes we are by now used to.

So, this made me wonder if I shouldn't take the opportunity to have the hull sanded for removing completely the old a/f - something which was never done before in the 13 years of the boat life.
Actually, thickness and roughness of old a/f layers is still acceptable, sort of.
But I don't think that a complete removal can be postponed by more than one or two seasons - hence my doubt about whether to bite the bullet now and go for it while the boat will be on the hard.

So, over to you folks: for how many years is it acceptable in your experience to keep putting new a/f over the old one?

Ref. the method for removal, I'm aware that sanding is not the only one, but it's by far the most popular around here..
And I was confirmed by several folks who made the job that the specialized company who does it is very accurate in bringing the hull back to bare gelcoat, without actually ruining it.
Otoh, everybody is telling me that after a dozen of more of years under a/f layers, gelcoat becomes porous no matter how careful the a/f removal is.
Therefore, it's very common practice to make an epoxy treatment while the hull is stripped to bare gelcoat, as a sort of insurance for the future, also on hulls that show no signs of osmosis.

Your views also on this matter would be highly appreciated.

As an aside, i'm also wondering if it would make sense to take the opportunity to go for some non-traditional a/f, like coppercoat or some foul release products.

Again, all views and experiences welcome.

Even more so if anyone can recommend specific products, and give also ballpark costs of these three jobs (old a/f removal, epoxy treatment, new "non-traditional" a/f).
I'm not asking about traditional a/f because I believe that we all know everything there is to know about it...
Fwiw, 2k Eur give or take seems to be the normal price for 2 layers on a 17m boat, around here.

Thanks in advance!

when I had my antifoul removal business, the average was about 7 years.

If the antifoul is all off and your moisture levels are OK, it's daft not to epoxy it. Gelcoat is not waterproof, epoxy is as good as waterproof. For DIY 6 coats of solvented epoxy in alternate colours is good for all sorts of reasons, including easy removal of antifoul in the future (you can breach just the top epoxy coat with your abrasive and the colours let you know where you are)

Personally I'd coppercoat it too and never have to remove antifoul again. Though thats another can of worms if you used solvented epoxy.

I'm not convinced on fouling release systems for hulls and I have trialled some. And if they don't work you need to remove and replace the gelcoat to use paint aver again, so I wouldn't be an early adopter. I think they work on props though now.

As for slurry v soda v dry blasting. The softer and slower the process, the less experienced/skilled the operator can be and still get a decent result. But it is all about the operator, gel coat is very soft and anything that can remove the antifoul can damage the gelcoat in clumsy hands. See the results that the actual operator has achieved. Good ones will leave some antifoul for sanding off, not try and achieve pure white.

 

[alant]

Some yards suggest sandblasting.
Personally, I would avoid that.
We had to remove some bad af so we used a slurry (wet) process that was so gentle that it didn't even scratch the plastic trim tab fittings.
So, I would recomend slurry blasting.

As far as teeatment goes, we applied Coppercoat which is epoxy itself so you can skip the epoxy layer after the removal of the old af.

Our Coppercoat cost about 5500 euros inc stripping but that was done at the same time as 3 orher boats. IIRC We are 110 sqm

Coppercoat isn't as good as af against fouling but it is really easy to maintain. Can last 10 years but ours might need recoating after about 8 years. That said, your cruising groungs aren't as aggressive as ours.
All that said, I recommend Coppercoat

Apparently soda blasting is a less aggresive alternative to sand blasting.

 

[wellf100]

I'm not convinced on fouling release systems for hulls and I have trialled some. And if they don't work you need to remove and replace the gelcoat to use paint aver again, so I wouldn't be an early adopter. I think they work on props though now.

Elessar, can you elaborate on your point regarding removing the gelcoat if you want to replace foul release coating please? I use aquamarine and have not read or been told any such thing. But happy to be proven wrong.

Thanks

 

[MapisM]

Thanks everybody, some useful food for thought.
One specific question on this...

Personally I'd coppercoat it too

Does coppercoat it "TOO" mean on top of 6 epoxy coats?!?

I asked some specialists around here in the meantime, and they confirmed me that with CC it's possible to use directly two coats of its own primer (a non-solvent epoxy resin, as I understood), and 4 coats of CC (also non-solvent epoxy based) on top.

Otoh, if going for traditional a/f, yes, I was also recommended a full epoxy cycle.
Actually with 5 rather than 6 coats, which allegedly is the supplier (International) recommendation.
They didn't mention to me the different colors though, which sounds like a clever idea.
Is there any specific product available in different colors which you used for that purpose?

Ref. old a/f removal, the most popular method around here seem to be dry blasting, with either walnut shell or garnet (an Australian mineral, as I understand).
I was told that slurry blasting is usually done with bicarbonate instead, but the cost is much higher, and allegedly not worth paying, provided that the operator works well with dry blasting.
Which is a given, sort of, considering that the company I got in touch with is widely used in this area, and they make literally hundreds of boats every season.