Cracked hull/accident please help

Discussion in 'Fiberglass and Composite Boat Building' started by CaptainReza, Oct 19, 2012.

  1. CaptainReza
    Joined: Oct 2012
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    CaptainReza Junior Member

    Thanks PAR and Frosty!

    I'll fix it with your help. This should not take more than a day. I learned a little when I did the bottom although that was not anywhere serious as what this is.

    Once I start grinding, I will post pictures to get guidance from you. By touching and seeing how soft it is, I doubt I can salvage anything, I probably end up having a hole and building upon that. My only concern is the bevel on top and sides.... Could I do this with 60 grit and a sander? I guess I'll order a grinder the way I am having luck lately......
     
  2. PAR
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    PAR Yacht Designer/Builder

    If by sander you mean a 1/4 sheet palm sander (hand shaker), then yes, but you'll make a career out if it. A better choice would be a DA, which will be useful for other jobs, like smoothing and fairing. The area affected will only be say 6" square, around each bit of broken laminate. In fact, you might be able to just grind out the worst of it, pack it fill of epoxy and then refair and paint. The epoxy will get into the broken up fibers, locking them down solid and some filler over the spot to make it smooth again.

    If it was me, I'd just hit the cracks with an angle grinder, exposing the broken laminate, feather back slightly, then arrange some way to place the goo in under pressure. All this means is a piece of plywood, braced against the hull, protected with some plastic packaging tape so it doesn't stick and a 2x4 to wedge against it while the goo cures. If you're real clever, you could inject through the plywood, into the damaged spot and when you remove the plywood the next day, it'll be nearly perfect, except for some minor filling and paint. This is asking a lot from a novice, so you'll be sanding a fairing your brains out as you learn, but if the boat was in my yard, that's one approach I'd take, to save some effort. Hell, I might even try to pigment the epoxy so the repair was very close to the color needed.
     
  3. CaptainReza
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    CaptainReza Junior Member

    PAR, brilliant idea but I may end up doing what you mentioned in the first part. That I know I am capable of doing.

    I am shooting myself in the foot since I saw an awsome angle grinder on Amazon last week for $65 (Makita), I should've bought it when it was on sale but its not much more now, I will buy one.
     
  4. CaptainReza
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    CaptainReza Junior Member

    Guys,

    What do you mean by "DA". Does that mean Dremel?
    I have a Dremel, it'd be so much easier for me to feather the edges with a Dremel since its small and I know how to work it compared to an angle grinder. Is that OK?
     
  5. PAR
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    PAR Yacht Designer/Builder

    DA is a dual action orbital sander. You'll make a career out of it with a Dremel too. A Dremel is for kidding yourself it's an actual tool. My electric toothbrush has more gonads than the best Dremel available.
     
  6. CaptainReza
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    CaptainReza Junior Member

    Thanks PAR!
    I have an orbital sander, I will hit it today.
    Question for you, when I build it up with small pieces of fiberglass cloth, can I do this in one shot or should I put a layer, wait until it cures then the next layer?

    Also from structural strength point of view, do you see the impacted area being a threat to integrity of the hull if ridden hard in rough water? I just want to see how good of a job I need to do or how nervous I should be when I am doing this job...

    Thanks,
    Reza
     
  7. PAR
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    PAR Yacht Designer/Builder

    The damaged areas are so small that doing them in one shot is they way to go. In this vain, you will have no worries about hull shell structural integrity. Of course if you where in my yard, I'd tell you about how boat's can split in two, from damage like this, as I handed you the estimate, you asked me to keep as low as possible. After you'd developed a good sweat, I'd let you off the hook . . . :)

    You're going to be fine, now get started, winter's coming . . .
     
  8. watchkeeper

    watchkeeper Previous Member

    Its very easy to cut a section of 1-2mm thick aluminium sheet same width of hole but longer - drill a hole thru the centre to push thru a piece of wire to hold the plate.

    Smear a coating of 2pack epozy glue on one face, feed the plate thru the damage hole then pull it up against the inner face covering the hole and secure it while the glue goes off then either snip the wire or pull it out.

    Sand and feather out the edges of the hole to taper the area around the hole giving youself an area of reduced hull thickness to build up with a wet lay up, once the patch is hardened use an epoxy filler top fair. Wet sand the prime and paint.

    Its a useful skill to have because hulls get banged up over the years
     
  9. CaptainReza
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    CaptainReza Junior Member

    Thanks PAR and watchkeeper!

    Please see pics.
    I bought a grinder, I went in 19/64 deep... This grinder with 36 grit sand paper would take material like laser... I didn't have much control over it ...

    Most parts are hard but one part was still a little soft and I thought if I grind a tad further I will have a hole so I stopped and started building up with many many layers of cloth in different locations and angles (small pieces). Now I am waiting to see what the outcome is before I go forward....

    Should I feather the top more or leave it alone?

    Please advise...
     

    Attached Files:

  10. CaptainReza
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    CaptainReza Junior Member

    Please make sure to give me feedback as I wont continue until I hear from you PAR and others. Don't want to continue on a mistake if this isn't OK....

    I can't thank you Gentlemen enough!
     
  11. CaptainReza
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    CaptainReza Junior Member

    I could not agree with you more.... Thanks so much!!!
     
  12. PAR
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    PAR Yacht Designer/Builder

    Just pack it full of thickened goo, slightly proud of the surface and let it cure. You'll be ready to knock it down flush and fill the little imperfections (pin holes, etc.). Agai a piece of sheet goods held flush to the surface can make fair it out a lot easier, though this is an advanced technique.
     
  13. CaptainReza
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    CaptainReza Junior Member

    PAR,

    Is it looking on the right track?
    When you say thickened goo, is it thickened epoxy?
    Did I take too much out? is the feathering OK?

    Sorry for all the questions :(
     
  14. PAR
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    PAR Yacht Designer/Builder

    To be honest, repairs this small are hard to mess up. The photos don't offer enough to answer your questions, but if it looks seamless under paint, you did a good job.

    Yes, goo is one of my favorite words for epoxy. From what I can see, all you need is to smear a coat of fairing compound over the area, then sand flush, in prep for paint.
     

  15. watchkeeper

    watchkeeper Previous Member

    Make sure you use epozy filler, polyester fillers are porous and don't hang on the same as epozy does.

    Good job
     
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