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Thread: Help/Advise with my 19 foot Center Console - serious epoxy/ply delamination issues

  1. #1
    Join Date
    Nov 2017
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    Malindi, Kenya
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    Default Help/Advise with my 19 foot Center Console - serious epoxy/ply delamination issues

    Firstly - as a Newbie to this forum, I am honored to be here. And I hope that some of you can give me some insight into the best way fwds.

    I built this boat myself from scratch, but I live in East Africa and the right materials aren't always readily available. Having said that, I tried really hard to use as best I could...

    Anyways... something obviously went wrong...

    So what was meant to be a simple transom extension has changed into a major rebuild at the very least.

    https://www.youtube.com/watch?v=j4LTRu4WEWM&t=33s

    Whilst I had the engine off to extend the transom, I decided to do a few modifications to my bilge. After grinding through some paint (so I could glue in a mounting block for a bilge pump), stinking smelly greasy grey water started seeping into the bilge from under where I had opened up the paint on the port side of the keel.

    About 5 liters of the stuff came weeping into the bilge; on further inspection/digging and to my alarm I realized that I can slide a hacksaw blade all the way under the motor well bulkhead and the port stringers.

    In the transom lockers, I had noticed a small crack where my chase tube comes out; water would sometimes get in here (I guess from where the hoses come into the transom well).

    I decided I better open this up and check if there was any water in there; and whether this was the cause of my problem.

    Well the PU foam was a little damp near where the chase tube came out - didn't think much of it till I dug all the foam out and there was a pool of water about 10 liters right at the bottom.

    More frightening was that as I was pulling the PU foam out, it was pulling up the fiberglass laminations with it.

    I decided to cut an inspection hole in front of the motor well bulk head on the port side; so one frame in front of the leaking transom well.

    This is a total disaster... on cutting the pu foam out, you can litterly squish the fiberglass up and down.

    I cut through this layer with a box cutter knife and to my horror, it appears that all the fiberglass has delaminated from the ply.

    This is worse than just a gap under the stringers. This means that the entire inner layer of biaxial (which makes up the "monocoque structure" has delaminated.

    The epoxy has turned to a sort of dark brown gooey, sticky grease; it was rock solid dry when I poured the foam 5 years ago; is this some strange chemical reaction?

    Has anyone heard of this before.

    Does this mean I am going to have to rip out all my stringers and frames?

    How do I prevent this in future?
    To sum it up, on further investigation, I think that issue is far worse than I had initially thought.

    I have opened up the sole towards the front of the boat and basically the delamination has pretty much spread everywhere. I am posting another video now which shows that the biaxial fabric is even lifting off the hull sides high up in the front locker of the boat.

    I think that this is obviously some sort of failure/ strange chemical reaction on the part of the epoxy; and may or may not be something to do with the water in the hull - I am still in two minds over this.

    You can see in the video that it is like the epoxy has broken down, it is sticky and gooey and I can smell amines; on places where it was on the ply wood, I can literally scrape it off with my fingernails.

    I would never have carried on building had the epoxy not cured initially, so there must be something going on.

    I know that the outside of the hull was sheathed using Ampreg 21 (www.gurit.com/sitecore/content/Old-Prod ... mpreg-21SP)

    As I recall, I ran out of that and I believe that the inside was done with Atul Lapox B11 and K-41 hardener.

    Which as I recall, this was very viscous and I may have mixed it and then placed the pot in a tub of hot water to lower its viscosity (which I believe is an approved technique) in order to get it to wet out the glass.

    I live in a place where this is the only resin available, and I believe that I did run it by the designer at the time.

    Unfortunately, the whole inner biaxial fabric was laid in the same day, so what ever issues stem for the resin, they must be pretty universal to the whole sheathing.

    Having said that, it surprises me, that there are places which are firm and strong (perhaps a better mixed batch from the same day, or the water never got to that part)...

    All this is fairly mute at this stage, as I really can't see any other solution than to gut the whole inside of the hull, and hope that the outside, with the different resin is fine.

    As far as the plywood goes, it still seems pretty solid, with no signs of rot.

    In any case, I boil tested all the samples... before building - as I am not convinced the BS1088 stamp was genuine!
    All plywood used has stood up to one hour of boiling, a night of freezing and an hour of boiling so far, so at least the glue is strong

    All I can say is that this is all pretty devastating...

    I was certainly under the impression though, that once cured and hard, epoxy was fairly inert; and that other qualities aside like viscosity, cure times etc, were more of a luxury to the builder than a necessity to the integrity of the boat.

    As I said before, there is no way I would have continued building with semi-cured resin... and all my resin samples were tested before laminating to make sure that they cured.

    I guess you live and you learn; and as the saying goes, "worse things can happen at sea".

    Personally, I am strongly questioning the logic of adding PU foam and completely trying to seal the various lockers.

    I think that next time each compartment between the frames will have a drain plug that allows any water that may have gotten in there to flow into the keel section.

    I would of course appreciate all thoughts on the subject - I suspect I have to gut the whole insides?



  2. #2
    Join Date
    Oct 2009
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    Default Re: Help/Advise with my 19 foot Center Console - serious epoxy/ply delamination issue

    I think your problems come from the foam, not the epoxy.

  3. #3
    Join Date
    Nov 2017
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    Malindi, Kenya
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    Default Re: Help/Advise with my 19 foot Center Console - serious epoxy/ply delamination issue

    Meaning the foam has reacted with the epoxy to make the biaxial delaminate from the plywood below it? Surely other people would be aware of this sort of reaction between PU and epoxy? Isn't PU used fairly regularly with epoxy coated wood boats?

  4. #4
    Join Date
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    Default Re: Help/Advise with my 19 foot Center Console - serious epoxy/ply delamination issue

    Expand in place foam is generally looked on as being junk. It absorbs water. When you mention 10 litres of gooey stink junk leeching out.... well that is something folks who fix foamed boats have seen before,sadly.
    Looks like you built a fine boat and I'm glad the ply hull is still good, but I would send that foam back to satan.
    bruce

  5. #5
    Join Date
    Sep 2005
    Location
    new zealand
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    Default Re: Help/Advise with my 19 foot Center Console - serious epoxy/ply delamination issue

    Damn, that's pretty heartbreaking.
    Unventilated spaces generally seem to cause problems, as they retain any moisture that gets in, and grow things. Just as a comparison, the John Welsford boat I built had a similar flotation space under the sole, but had multiple large (100mm+) diameter holes in all the frame webs, and removable inspection ports - that whole space could be aired out, and there was no foam or anything.

    In the delaminated areas, is the plywood damp underneath? It seems like a really odd failure.
    I'm wondering (no offence) if your "epoxy" was actually polyester? That stuff is notorious for just peeling off just about anything (even itself) if the surface wasn't prepped properly, or the mix ratio was wrong, or it was too cold, or you din't stick your tongue out right.
    One other possibility (if it was epoxy) - did you pre coat the plywood, and allow the epoxy to cure, before applying the fibreglass?
    And if you did that, did the amine blush get washed off before the glass went on? That is the slightly greasy/sticky film on the surface of newly cured epoxy (some brands are worse than others), that wont do anything good for bond strength.

    Edited
    OK, Lapox B-11, definitely an epoxy http://www.apipl.in/Buildingandcivil.aspx
    It says medium viscosity, did the glass wet out properly? It should have gone almost invisible if the resin soaked through properly, and went into the wood. Most laminating epoxies are describe as low viscosity FWIW, and getting that to wet out through two or three layers of lightweight 6oz glass where there are overlaps, can take a fair bit of effort. Heavier glass and thicker resin??

    Pete
    Last edited by epoxyboy; 11-13-2017 at 02:51 AM.
    Don't underestimate the power of stupid people in large numbers!

  6. #6
    Join Date
    Nov 2017
    Location
    Malindi, Kenya
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    Default Re: Help/Advise with my 19 foot Center Console - serious epoxy/ply delamination issue

    Thanks for the responses; I am continuing to gut the boat and investigate. I suspect that the major failing is the epoxy; the water intrusion I am hoping was secondary and that hopefully the ply is still OK - and thoughts how to check this?

    The bits that I have investigated are still covered with a greasy slimey layer of semi-soft epoxy; so I am hoping that this in itself was some sort of barrier to the water. Like oiling wood!!

    If you have watched my video clip, where there is delimitation quite high up in the bow locker, you will see that there is no water in there, just delamination.

    Either way, the boat design is such that it is a core of plywood, sandwiched between two layers of biaxial fabric (outside and inside) and then the stringers are taped to this biaxial fabric. As it is the fabric between the hull and the stringers that is delaminating, either way, I am thinking all the stringers will have to come out.

    I can think of no other soln.

    I know that the outside of the hull was done with a clearly branded epoxy from a reputable dealer in South Africa; I then ran out of this; and can only assume that what I was sold locally perhaps wasn't the stuff that it said it was.

    I can only keep demolishing at this stage...

  7. #7
    Join Date
    Mar 2007
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    East Quogue,NY
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    13,634

    Default Re: Help/Advise with my 19 foot Center Console - serious epoxy/ply delamination issue

    Polyester blisters contain a brown greasy liquid. It's the result of a chemical reaction between the cured resin and water in the anaerobic environment between laminations. Perhaps a similar process occurred aboard your boat, epoxy use notwithstanding; the foam held water and kept out oxygen.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

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