Fiberglass repair

Discussion in 'Boat and Accessory Building' started by Seasider, Feb 18, 2016.

  1. Seasider

    Seasider Paddler

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    I managed to rip out the grab handle hook while making another emergency repair. The handle worked fine for carrying the loaded kayak so the original fiberglassing was good.





    I am familiar with basic fiberglass repair but am not sure how to tackle this. It seems likely that I would need to grind out a section
    and add glass followed by the gelcoat. How much would need to be ground out or is there some other approach?
     
  2. JohnAbercrombie

    JohnAbercrombie Paddler

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    What brand of kayak is that?

    IMO, a longer stainless rod would have helped prevent this, with more glass to support it. That's a lot of stress for a very narrow piece of glass (and gelcoat) to support. Never mind, 20/20 hindsight is easy.

    That's got to be one of the toughest spots to do a repair. Is this at the bow? How large is the forward hatch? (Can you access that area at all - with a stick on a brush or with a socket wrench on the end of a pipe- via the hatch opening?)

    Is a heavier SS rod a possibility, inserted from above into the existing 'pockets' ?

    Is that also the anchor point for the deck lines?
     
  3. Seasider

    Seasider Paddler

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    Hi John, the kayak is a Nimbus Telkwa HV. Other than this, the fiberglass craftsmanship is excellent throughout the boat. I like the design of the Necky Looksha a bit more than the Telkwa though. The Telkwa has a long narrow bow which isn't necessary for my purposes.
    The damaged hook is on the bow and it is also an anchor point for the deck lines. It is not accessible from the front hatch because there is a small bulkhead about 6 inches from the bow , which blocks access. I agree that maybe a different hook might be a solution, but it seems like it would be a lot of work and that maybe I should try to use what is there.
     
  4. JohnAbercrombie

    JohnAbercrombie Paddler

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    So, a repair from above will be necessary, I'd think.
    I'd get in touch with Nimbus and give them a 'heads up' about the problem (and this discusion) - they may have some ideas.

    If it were my boat, I'd be considering a couple of alternatives.
    1) Stick a new/heavier/longer/straighter SS rod into the same recesses and repair/reinforce with milled glass fibers and thickened epoxy.
    or, more drastic:
    2) Use a jigsaw to cut out the fitting area, repair or change the setup, and replace the piece of the deck and laminate glass over.



    Either one will require some cosmetic 'hiding' of the repair - I'd probably resort to painting over the tip of the deck if my initial attempts with gelcoat didn't do the job. It's more important to have a trustworthy anchor point than good looks, IMO. (You are lucky this happened at home, not when you really needed that anchor to be strong, on the water.)

    Is that really a bulkhead up forward, or just an 'end pour' of thickened resin? If you poke around in the holes where the SS rod used to be, do you hit air or solid resin? If it's an end pour, you could bond a U-bolt into it.
     
  5. Seasider

    Seasider Paddler

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    I now think it is likely an end pour. I tapped around the bow area and it sounded equally hollow as other areas so I thought it might be a bulkhead. If it turns out to be solid then it will be easier to repair.
    The boat is around fifteen years old so maybe Nimbus has since fixed this seemingly obvious weak spot.
    I will investigate further. Thanks for the help
     
  6. mick_allen

    mick_allen Paddler & Moderator

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    ditto. I have no idea what Steve will say, but I'd get a longer rod, curve it to the same amount, drill one hole out longer - and see if you can dry thread the longer pc thru the previous holes. The curvaceous shape will make this possible: rotate the rod 90 degrees, and push all the way in one side, rerotate, and back it to thread into the other hole. Successively drill out one side [broken one makes sense] in order to allow this to happen.
    Turn boat upside down and prior to insertion, inject lots of whitened epoxy mush into the holes and then slide in the SS steel rod. Let set up and then glue down the little bits with whitened epoxy. If the whole area looks really weak, preinject good epoxy mush and then drill out after setup.

    That'll be fairly cosmetic, really quick, quite easy, and pseudo-strong - and it'd be what I'd do - but it wouldn't be perfect.
     
  7. Astoriadave

    Astoriadave Paddler

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    An ugly failure, and a very questionable installation in the first place.

    I would be much more aggressive, and hog out the recess completely, getting back to sound interior material. Then prepare a solid piece of SS rod, conforming to the deck curvature. Roughen it thoroughly where it will disappear under the hole edges, about 2 or 3 cm of overlap under intact deck, each end. Prepare a mix of milled glass, slow hadener and resin, and fumed silica, (aka Cabosil) to a thin peanut butter consistency (successive batches, so the mass of each batch does not promote a terminal exotherm), and spoon or squeeze (from the plastic bag within which you mixed it) the mixture to completely fill the hole. Some vibration on the hull may be needed to get the bubbles out. Before the mixture begins to set up, insert the rod and backfill with more resin mix to completely fill the recess flush with the deck, hooking the rod in the center with a loop of wire and pulling up during cure so the rod remains fixed during cure. At the green stage, or maybe at the fully cured stage, dig out the excess solid mix to re-form an attractive hollow, sanding the surface to whatever degree pleases you.

    Apply System Three WR-LPU in a contrasting colour, around and within the repaired surface, several coats, as a badge of honour for your elegant, bombproof fix. Send photos to the manufacturer and ask for a substantial reward to compensate you for their insubstantial design.
     
  8. mick_allen

    mick_allen Paddler & Moderator

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    I agree and am surprised - especially for an end fitting. I would have thought that the rods there would at least have been longer.
    good point, Dave.
     
  9. Roy222

    Roy222 Paddler

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    The repair should be very simple.
    Simply get a longer piece of SS rod, bend it into a large arc. ( add about 25mm at each end) Mark the center point.
    Next simply drill out the existing holes using a drill slightly larger in diameter then the rod.
    Next feed the rod in the rear hole, being careful not drop it thru the hole, until it clears the front hole.
    Next feed the rod into the front hole. - feeing to the front
    Next work some epoxy into the holes and around the rod.
    Next apply upward pressure on the rod while the epoxy cures.
    After the epoxy cures patch and build up the damaged area.

    Getting the drilled out holes just big enough to allow you to feed the rod will take a little trial and error.
    Be sure to put downward pressure on the drill motor so as to not enlarge the holes on the up side.

    Rod extending 25mm under the hull should provide plenty of strength.

    It is worth a try. You might experiment with a piece of coat hanger wire first.



    Roy
     
  10. JohnAbercrombie

    JohnAbercrombie Paddler

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    The problem with using a curved rod is that any sideways force will tend to rotate the rod and loosen its attachment to the deck.
    Where the underside of the deck can be reached, this problem can be (somewhat) reduced by molding a good 'glob' of thickened epoxy around the rod ends - usually with glass cloth over that.
    If a simple rod replacement is chosen for this repair, I think a straight (larger diameter) rod would be a better bet.

    I'm still voting for burying a U-bolt (with nuts) into epoxy-filled holes, if indeed there's an end pour in there.
     
  11. Seasider

    Seasider Paddler

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    The front hole is solid. The rear hole goes into an airspace after about half an inch of material. I'm thinking now that a longer piece as described by Roy and Mick would be the best. I thought it might be a good idea to also grind a groove into the section at each end of the rod to prevent it from working loose since one part of the rod will likely be into an airspace.
    With that in mind, what sort of material would be best. I was thinking a resin with some fibre mixed in or will it be necessary to use epoxy and If thats the case, I assume the small tubes available at hardware stores would do the job.

    If i end up drilling into the airspace with a hole large enough for the rod, then I it might be very difficult to get a good seat in the resin or epoxy material. Maybe I need to avoid drilling into the airspace. Any ideas? Also, I don't have a heated area to work so this will need to wait until warmer weather.
     
  12. JohnAbercrombie

    JohnAbercrombie Paddler

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    I'd consider turning the boat upside down (deck down) to give the best chance of getting a bond between the rod and the deck.

    I've never had much luck with the tube epoxy from the hardware store, but it's been years since I've used that stuff- perhaps the selection and quality is better nowadays. When I did use it, it always seemed a bit on the rubbery side when cured; the 5-minute kind was the worst. JB Weld (from the auto store) is one product I've used more recently that worked well, but it is quite slow-curing so would need a warm spot.

    BTW, more than once I've used a small fan heater in a 'tent' to do an epoxy repair, when I didn't have a warm shop available. For something small like this job, even a hair dryer or heat gun with patience and a careful touch would do.
    (This assumes you are not up to your knees in snow and ice.....)
     
  13. Astoriadave

    Astoriadave Paddler

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    The 5 minute epoxy is crap, plain and simple. Not able to withstand constant immersion in water. Not suitable for marine use.

    Yes, you need to form the metal rod into bends at the ends to prevent it levering itself out again, or, thoroughtly roughen its surface, such as the groove you mention. Several grooves would be better.

    No way would polyester resin, aka "fiberglass resin" be adequate by itself. Mix in milled glass fibers and some thickener, about 1:4 ratio to make a thick peanut butter consistency. Thickener can be wood flour or cabosil, aka fumed silica. All these are available at a decent marine store. Then add catalyst if you insist on using polyester resin. Epoxy is much better for a job like this. And, you should practice on using these materials before committing to reinstallation of the rod.

    As to a heated workspace, a simple plastic tent will be adequate, if you heat the area a bit, to reach 60 F or so, using fast hardener with the epoxy.

    See previous post about overfilling the cavity and then carving back to form a recess under the rod.

    This is not a simple repair. If it intimidates you, get some help from someone experienced with epoxy.
     
  14. Seasider

    Seasider Paddler

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    So this is what I did:




    Not sure why ,but I can't seem to get this text to move to the end of the post where it belongs. Some of the pics are out of order too.
    I have several other gel-coat repairs to make so will finish this up some time later when its a bit warmer.
    Does anyone know if the gelcoat will stick to such a small repair as this. Otherwise I will add some more epoxy to finish the repair.
    Thanks all for the help
     
  15. Astoriadave

    Astoriadave Paddler

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    Seasider,

    I hope that works. Looking at this photo, I am concerned that some of the exposed fiberglass was damaged when the original metal rod was pulled out.



    The gel coat may keep things together. If it does not, and you decide to reinforce that area as part of a second effort, get some fiberglass fibers, aka milled glass fibers, mix them with the gel coat or other resin of your choice, and add in some thickener such as Cabosil or fumed silica to make the mixture about the consistency of peanut butter. Then add the catalyst and mix well. The glass fibers reinforce the mixture so that it will be much stronger. By itself, gel coat is not very strong.

    It looks like you roughened the new metal rod. That should help, as will the added length.

    If the new rod pulls out, it would be a good idea to dig out as much of the exposed fiberglass as you can and replace it with the mixture detailed above, which should adhere to the good fiberglass exposed by digging. Digging out the old stuff is important, much as when the dentist removes decayed material by drilling before adding stuff to make a dental filling.
     
  16. Roy222

    Roy222 Paddler

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    That should hold, if, the rod can develop some shear strength with the side of the hole. 7 mm of penetration could develop close to 200 lbs shear strength. Divide this estimate by 10 and you still a have 40 pound pull out.
    Any way, good luck with the fix!


    Roy