How long lasts Fiberglass?

Discussion in 'Materials' started by Vega, Apr 26, 2006.

  1. Guillermo
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    Guillermo Ingeniero Naval

    I think honestly you should be careful. Probably they are trying to 'create' a market as Mike says. Epoxy barriers may even be a very, very bad thing, if laminates have already embeded moisture. They need to be absolutely dry before applying.
    Epoxies are not impermeable. They just allow the passing of water at a lower rate that gel-coats, that's all. So if a boat has moisture within laminates after being ten years afloat, that's not so rare, and probably neither worrying if moisture-meter lectures are low (But anyhow more worrying than with gel-coats, because with epoxy barriers hull will not dry out even after several months ashore).
    Fishermen applying three coats of epoxy every three years are the more concious and careful fishermen in the world, to say the least! On the other hand, or they are being cheated, which is not so easy with fishermen, or....
    By the way, last time I've been in Nazaré by boat, there was no Marina and I had to sleep anchored under the protection of the cape. It was a rolly night, indeed!
  2. Vega
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    Vega Senior Member

    You should cruise more.:p The Nazaré Port is 23 years old, and the place where you have stayed at anchor just looks good.:p If you stay there, the boat will roll a lot, even in settled weather.

    I have asked to the shipyard boss about the 5 year period, for applying a new epoxy barrier and the answer was quite simple.

    He is a very serious kind of guy and gives full warranties to all works made in the shipyard, so regarding the warranty on the job of applying an epoxy barrier in a hull, he gives the same warranty the different suppliers give him.

    I have checked out in the technical papers of the products, and they never talk about the time effectiveness of the product and if you ask for a warranty I doubt they will give you any, but if you are a significant costumer, they will have to give one, otherwise they don’t sell.

    So about those warranties, he says the longer that he knows of, is 5 years and most of brands will offer only 3 years.


    "Any boat represents a substantial investment. Maintenance problems unique to polyester/glass reinforced boats, particularly the hull, can threaten your investment as well as detract from its performance and appearance.

    An epoxy matrix is more resistant to hydrolysis than a polyester matrix. In general, the structure of the ether linkage within the cured epoxy is more stable than the structure of the polyester. This means that the epoxy will not be broken down by water as easily as the conventional polyester resins."

    "Protection is always better than cure and it really does make sense to protect a new boat as well as an older craft.

    To achieve this protection it is necessary to sheath the hull with a water barrier to seal the surface. This is done over the existing gelcoat".

    "Epoxy resins have exceptionally low water permeability, and if applied to a hull which has no evidence or sign of any chemical change in the laminate caused by hydrolysis, and provided it is applied to the correct specifications it will give many years of protection".

    There is a little data available on the true long term effectiveness of any coating in preventing blistering in a variety of climates and conditions.

    And looking at the Osmograph (westsystems) we can see that, after 6 weeks of emersion, even the best epoxy barriers only have an efficacy of 85%. Considering that the “ epoxy will not be broken down by water as easily as the conventional polyester resins”, (but with time, it will be broken nonetheless), what do you think the efficacy after 10 years will be, 10%?

    As you should not apply an epoxy barrier on a “hull which has no evidence or sign of any chemical change in the laminate caused by hydrolysis”, you have to be sure that you maintain the efficacy of that barrier in acceptable levels and for that nothing better than to stick to the judgment of the ones that know more about it, the epoxy barrier manufacturers.

    And if they give you a 3 or 5 year warranty on the efficacy of the product, it will be very naïf to think that the product is still effective after 10 years. If they could they would give it a 10 year warranty, it would be good to the business.

    I believe they are right when they say that “protection is always better than cure”, and probably cheaper, because anyway 5 years is the time to clean the hull of all anti-fouling and have it inspected. So if you apply some new coats of epoxy barrier, the cost will be a fraction of what it will cost, some years later, to take away all the gelcoat and make a full reparation.

    Besides, as we have seen in this thread, you can not repair the structural damage caused by the Osmose on the composite, or putting it different words: Osmose “will induce stronger drops in the composite thermo mechanical properties due to higher water uptakes”.

    Everything considered, it seems to me that the advice given to me by the owner of the Nazaré shipyard, regarding boat protection against Osmosis and weakening of the composite by excessive water content, is a sound one.

    What do you think guys?

    Attached Files:

  3. Roly
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    Roly Senior Member

    Good stuff Vega! Much obliged for your research. There is nothing worse than shelling out good money not knowing whether you are applying the optimum product, and how effective the industry rates that product.
    As Mike said, urban myths prevail in the industry, and it is easy to be misled by the wealth of misinformation. The MEE test has been out for a considerable
    number of years but little heed is given to it.
    BTW, just why did did West Sys. stop at 6 weeks? Like you,I would be curious to know
    what happens to the curve long term.

    Some time ago, I prepared 50mm cubes of balsa with 6,5,4 coats of 105/205,105/205+ 2 barriercoats,polyester+gelcoat,+ control, and was going to drop them down to 100' for an accelerated emersion test at 3 atmospheres). (Weighing at monthly intervals)
    West told me not to bother. As the MEE was available!
    That was 12 months ago,and now I am ready to glass.:(
    Wish I had done it for a little more insight.
    p.s. I realise the 100' thing is not ideal but just how do you simulate conditions and accelerate the time frame without pressure?
    The MEE tests, as I understand it were with steam, 100% relative humidity in closed camber @ STP. 1 AT./25degC.
    Perhaps just a temperature controlled steel camber, with the cubes immersed and the air volume above @ 3 atmospheres would have been easier than dropping them down on an anchor warp!
  4. MikeJohns
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    MikeJohns Senior Member

    I remembered a link I have been trying to find ( must learn to organise those bookmarks ): Download the PDF on Osmosis it is a good ref document to give to clients.

    What are you building? I understand your commitment now :)

  5. Roly
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    Roly Senior Member

    It started as a repair and rapidly turned into a rebuild. Long story!:rolleyes:
    It has been re-engineered to Tom MacNaugtons scantlings,+ a "bit";) with 810gm triaxial both sides.
    We are trying to make the most of it as it is probably the only boat we will own. We consulted with experts during the process, but most were pretty damming during the dismantling.
    Progress at

    We missed the summer "window" to glass and now temperatures and humidity level are a worry. Guess we will wait for a nice big "high", heat the hull and go for it. Needless to say, after fairing, substantial barrier coats will be applied. (aluminium powder or copper)
    Thanks for your interest.
  6. Guillermo
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    Guillermo Ingeniero Naval

    Of course taking care of one's boat as often as posssible is better for the boat than the contrary, absolutely. Ideally we should take care of them every single day, as a boat is just one step downwards in caring demands than a woman....:D (Just a joke, girls. Don't blame me out)

    But keeping things reasonable, I do not find a reason to do as that boatyard of yours says. In my opinion a properly laminated hull in sound condition does not mandatoryly need that kind of intensive maintenance. I know of repaired hulls (after having suffered severe blistering problems), kept afloat in warm waters for the whole of the year after that, for more than 15 years now (Like the Banjer of my friend Brian Hull, in Port Moresby, Papua N.G.), that are still in sound condition, just with the subsequent standard yearly haul-out and bottom painting. Of course every single boat is a particular case, but I'm speaking in general terms.

    Warranties form manufacturers are good and give us a clue about duration of things, but we have to take them with a healthy care, based on our own or others' experience. Nobody buys a new car just when his actual one's warranty expires....

    About moisture meters, and not only, have a look at this:

    From there:
    "I work primarily in an area where boats often go three to four years between haulouts. The water is warm, clear, and clean-a veritable laboratory for studying the effects of water and continued exposure on FRP structures. After using a moisture meter on over 1,000 surveys, I have yet to see a recently-hauled boat that indicated anything less than "high" (7+ on a scale of 1 - 10) on surfaces below the waterline. These readings have been taken with a variety of meters, including Sovereign, Novanex, GRP-33, and Protimeter. The ban of tin compounds for anti-fouling paint and the advent of high copper loads along with special interior barriers have now given consistent "pegged" readings on nearly all hull bottoms. The end result is that I ignore meter readings below the waterline while still paying close attention to exterior surfaces above the waterline, particularly around through-hull fittings and any deck hardware. Meter readings inside the hull are often helpful, but care must be used in assessing potential problems where the bilge has been allowed to hold water. (A brief aside: NOTHING good ever comes of water in the bilge.)"
  7. Guillermo
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    Guillermo Ingeniero Naval

    Very nice paper, Mike.

    From there:
    "My own experience is that early treatment of osmotic boats tends to be less successful than treatment of vessels with advanced blistering...."
    I firmly agree.

    Roly: You're involved in a nice rebuilding project! I don't dare to ask about the cost...!
  8. hansp77
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    Wow Roly,
    I can only repeat the very same words that many a observor has said to me as they walked past our hardstand. (which usually strike me as particularly annoying).

    Big Job!

    and damn good work. I certainly know that repair turning into a rebuild feeling. Long story indeed.
    If this is likely to be your only boat, then at least it will be a boat you will be sure of- from the ground up.
    When I look at the job you are doing, it makes me feel like I have just been scratching the surface. I will have to show your photo's to my girlfriend. It might make her feel a little better, make her feel like it was not in fact the mini-titanic that I bought for us...

    Nah its never been that bad, but I know that sinking feeling when one small repair job opens up three more, which in turn opens up three more, which means this might as well be replaced, which means that will have to come off, which reveals one more repair job, which opens up to reveal three more, which...........
    It just goes on.
    Sometimes the days we weren't working on the boat felt like more progress. At least we weren't moving backwards!

    Anyway, good luck.
    She looks like a beautifull boat.
  9. Vega
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    Vega Senior Member

    Nice hull Roly.

    The boat seemed to be in perfect condition...apearances can be misleading.:rolleyes:

    But It could be worse, it is a lot more agreable to work with wood:p

    Seriously, it will be worthy, It is really a nice boat.;)
  10. Vega
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    Vega Senior Member

    Hey Guys, this is funny!

    Someone has given me "bad reputation points" on this thread, and has explained:"Vega has gone out of his way to make sense of this subject".

    Well, I will try not to make sense next time:p :p :p :p
  11. craig mclean
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    craig mclean Junior Member

    I've heard that osmosis can also be accelerated by electrolosis. Example in bodies of water where power cables are submerged. And that boats with metal gas tanks draw current/electrolosis,through the glass thus introducing osmosis. Ive seen some boats that show osmosis after only 8 years, that contained metal gas tanks. but when we switched to plastic tanks the problem dramatically reduced itself, note that we did not change resin,lay-up schedules or gel coat. what do you all think?
    1 person likes this.
  12. Roly
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    Roly Senior Member

    A thousand apologies Vega;That was supposed credit! That is the first & last time I try and give reputation points.:eek:

    And, I am trying to rebuild my boat?
    Doesn't bode well!

    I will try and reverse it.

  13. Vega
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    Vega Senior Member

    Roly, don't bother...I found it rather amusing...:D
    Not a problem, I really don't care about that.:)
  14. DanishBagger
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    DanishBagger Never Again

    Hehe, funny with you two.

    I have to say a thing or two about the subject as well.

    This is really interesting, but what I can't figure out is teh comparisons. The reason is that you cannot just compare "epoxy" with xxx product, unless you state how many layers and so on there are.

    Of course, in real life there will be difference, but are they those numbers?

    Let's use the ten-percent example after ten years. Yes, maybe it will onle be ten percent, but what happens if you have put another layer on there? If you have it painted, lacquered and so on.

    Basically, what I am saying is that one-layer might have, say 10 percent chance after ten years, but how about four layers, plus paint, all of a sudden we might be up to 95 per cent again.

    (did I make sense)?

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    CORMERAN Junior Member

    Re: EPOXY life expectancy.

    There is NO easy and difinitive answer.
    You can only deal with this matter on a case by case basis.
    We are doing a long term test of a composite epoxy.
    Since 1988 , a vessl we were involved with, has been imersed
    in sea water.
    It started out at 65'. Recently it was extended. A survey was required
    and the surveyor reported "..... that inside, below,she's as dry as a bone."

    This is antedotal evidence only - but it's useful to know.

    One needs to consider: LIGHT destroys plastics. Not just sea water.
    There's a lot of things - in process here.
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