Gouged my coaming - ugly, but not terminal.

Discussion in 'Boat and Accessory Building' started by KayDubbya, Apr 14, 2013.

  1. KayDubbya

    KayDubbya Paddler

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    Got a bad case of butterfingers this morning and bashed the coaming of my boat on my roof rack. The gelcoat is gouged right down into the fibers. There's two inch long pieces missing from the top, but the underside of the coaming is intact, as far as I can tell. Any suggestions of how to fix this up would be appreciated. I'm trying to decide if I should attempt it myself, send it out to a "professional", or just burn it down and claim the insurance.
     

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  2. Reef

    Reef Paddler

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    I have to admit, looking at the photo I am confused as to what angle/what I am seeing?
    Others might be able to decipher the shot more easily. Have you got wider shot?
    But while we are at it, what boat? layup?
     
  3. KayDubbya

    KayDubbya Paddler

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    Here's a bit of a wider shot. It's a fiberglass coaming on a fiberglass boat (NDK Explorer). The shot is from above the boat , looking down. I hope that helps.
     

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  4. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    That doesn't look too bad -- appears mostly cosmetic. Should be a simple fix. Most shops should be able to repair that easily.
     
  5. Alana

    Alana Wave Seeker

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    It looks like it's just gelcoat damage. Check the underside for fractured glass, if not it should be a simple fix... no need to take it to a professional.
     
  6. Astoriadave

    Astoriadave Paddler

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    I see fractures and holes. Needs glass and resin buildup, I suspect. Probably have to fair back little ways into solid material. Easy for a shop to do, or you if you are handy with resins and glass. Matching the color might be the trickiest part.

    Must have really whanged it on the rack.
     
  7. KayDubbya

    KayDubbya Paddler

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    Yes, Dave, I really did smack it. The question is should I use this as an opportunity to gain some glassing skills or am I likely to make it worse? If I do decide to fix it myself, what's the best/simplest fix. I'm not hugely concerned about color matching the gelcoat, simply because the way it looks now is so horrible that a different shade of black would be an improvement. I'm just completely new to this so I'm not sure where to start.
     
  8. Astoriadave

    Astoriadave Paddler

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    If it were my boat, I would use epoxy resin and glass. But you would not be able to approach the original color. Also, once an area has been epoxied, you won't be able to get polyester resin (see below) to cure over it without a barrier coat. Epoxy is a two part resin system easy to measure out in small quantities, and available in several speeds: fast cure, medium, and slow, permitting work at lower temps if you have to, or allowing slow work if you are slow yourself. :wink:

    OTOH, using polyester resin and glass, you can get a tinting kit which allows you to color the resin. I think, from the photos, the resin is black all the way through. That would make reshaping the rough work back to the original smooth curves of the coaming easier, and no need for a final gel coat of a different color. Polyester resin uses dropwise amounts of a catalyst for hardenining and curing. In my hands, small resin jobs were always tricky to get the right amount of catalyst.

    You being a resin virgin, might be best to take it to a shop and get a quote ... then decide what to do. Or, could be a buddy in Kelowna might mentor you through this, maybe. That is kind of a tricky surface to tackle as a first resin project.
     
  9. JohnAbercrombie

    JohnAbercrombie Paddler

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    Don't feel too bad - that doesn't look like a very strong layup on the coaming anyway (mat, not completely wet-out + heavy gelcoat).

    I'd probably use polyester resin, milled fibers, and black gelcoat to repair that.
    Polyester resin is cheap enough that you can afford to do a lot of 'trial runs', applying to scrap wood or plastic, to 'get a feel' for the speed of cure and workability.

    If you are in Kelowna, you have Industrial Paint & Plastics in town. The Victoria IPP branch staff have been quite helpful (and knowledgeable) when I have come to them with questions, so it might be useful to print out your pic and take it in to the store for a chat.

    If you have a local 'glass guy', it will probably be as cheap to have somebody else do the job, unless you want the experience, and the materials for your spare parts shelf. Your call. If you decide to do it yourself, some creative use of tape to build a 'form/dam' will help keep things in place.

    I would try to avoid just filling the 'hole' with gelcoat, as gelcoat is weak and brittle 'on its own'.

    BTW, you can get black pigment for tinting epoxy, but as Dave says, the colour match won't be exact (it's hard to get epoxy to buff up to a shine like gelcoat).
     
  10. Astoriadave

    Astoriadave Paddler

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    Good catch, John. I did not pick up on the poor job on the mat wet out. Seems odd for what must have been a vacuum job.

    Kay Dubb -- John has the poop on this. Agree totally with his suggestions. Go for it. Sounds like the folks at IPP might be a first stop. This might be a lot easier than I thought. Once you have done one fix like this, you will have the skills and confidence to do more the next time your boat gets some rack rash. Good way to meet damsels in distress, too ..."Dear man, you can fix my boat?!!" swooon :wink: :D
     
  11. nootka

    nootka Paddler

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    Looks like an opportunity to learn about epoxy etc.
    IMHO, NDK makes great hulls from inferior materials. So I'm not surprised to see the mat.
    (I have 2 NDK boats)

    You should buy a small quantity of epoxy (ie west system 105-A & 206-A), and some 6oz glass.
    Then you can fix this and any future dings. You'll need gloves & a vapour mask too.

    Since the fiberglass is not obviously cracked, I'd
    A) smooth the edges of the gelcoat
    B) glass in one layer and TRIM it to fit the hole (with a heavy exacto knife), after it hardens slightly
    C) cover with black gelcoat after the epoxy dries

    and you're done
     
  12. RoyN

    RoyN Paddler

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    This is a non-structural part of the boat. I'd go get some black gelcoat and fill the chipped out area and sand smooth and call it good. If you already have a source for gelcoat, I'd probably use what ever colour is available for the least expense since you cannot see the when the sprayskirt is in place.
     
  13. Astoriadave

    Astoriadave Paddler

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    Nootka,

    Will polyester gel coat cure over epoxy?
     
  14. KayDubbya

    KayDubbya Paddler

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    Thanks for all those good suggestions. I did a quick trip to IPP this morning to see what they had. The neutral gel coat is available in a small can for $17 and $11 get the black tint (out of stock until tomorrow, unfortunately). I didn't price out and epoxy or glass, since the repair is under two inches long. I'll check into their smallest size of 105-A & 206-A on Tuesday and then decide if it's worth fixing it "properly". IPP suggested cleaning the area with TSP and then acetone prior to applying several layers of tinted gelcoat. Good/Bad idea???

    John, I'll follow your suggestion and take a picture down with me so they can have a look.

    Thanks all. I'll post the aftermath once I've finished.
     
  15. nootka

    nootka Paddler

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  16. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    Definitely a good idea -- the surfaces must be clean for a good bond. Listen to the professionals. ;)
     
  17. KayDubbya

    KayDubbya Paddler

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    Very much so. Eight days and counting though. Can't wait.
     
  18. Mark_Schilling

    Mark_Schilling Paddler

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    Thought I'd throw in my $.02. I, too, own 2 NDK boats (3 if you include my wife's!), and I agree with Nootka - they make great boats with inferior materials. I'd probably say they use more material to make up for it - their QC isn't always great but the boats are about the toughest out there. I've got plenty of experience 'prettying-up' my boats and helping friends with cosmetic and more substantial repairs, plus building a Pygmy a few years back. More than a few gel-coat stained shirts adorn my closet these days. :)

    Since the damage is small, and not in a high-stress area, I wouldn't bother with glassing it. Gel-coat will 'stick' nicely to the exposed glass you can see there, since there's quite a lot of texture (roughness) to it. If it were the front of the coaming or anywhere on the hull, I might put a small fibreglass patch on with epoxy before gel-coating, but in this case, the damage is basically cosmetic. Test the area first - if the damaged area seems a little more flexible than the surrounding area, glass and epoxy might be wise - but the chance of this area failing in any way is almost zero since there's really no stress on it (unless you drop the boat upside down on your roof rack, for example!) :-o

    As for gel-coat, make sure you get the waxed stuff (IPP will give you the right stuff, I'm sure). You won't need much pigment at all - add as little as you can to get the right colour. Black is the easiest colour to match so you're lucky - if you do it well, you won't be able to see the repair when you're done.

    I've heard that TSP can result in inferior bonding, particularly if you don't get it all off. Personally I'd skip this step - clean the area well, and give it a good hard wipe with acetone on a rag (it'll clean up just about anything, including gel-coat). If there are any little chips in the surrounding gel-coat, pick those out too. Mix a bit of waxed gelcoat with pigment, then mix in the correctly minute amount of MEKP (it's the catalyst you use to cure gelcoat). Be sure to mix it really well, getting all the gelcoat off the sides of your mixing container etc. There's no point in doing more than one 'layer' - it won't cure if there's air around (hence getting waxed gel-coat - the wax rises to the top, blocking oxygen from getting to the gel-coat and allowing it to cure), so one big 'lump' will actually cure better than smaller layers. The only benefit of doing it in smaller amounts is that it may run or sag slightly. If you err on the side of more MEKP (one or two extra drops, not a big amount or it won't cure!), warmer temps and lower humidity, it won't have much chance to sag before it starts to cure. Oh - be sure the area has completely dried before you start anything. Fibreglass will absorb a small amount of water (not as much as kevlar, but some) so if it's normally outside, let it dry properly in your garage etc. for a day or so first.

    Once your gelcoat has cured, sand it down. I generally start with about 220 grit to get it down to the level of the surrounding area. Then, increase your grit size by about 1/2 each time (so from 220, I'd go to 300, then 450+/-, 600, 1000, and finish up with 1500 if you can find it - Lordco can be good). Anything about 600 grit or higher (finer) should be wet-dry paper, and wet-sand it. It's messy, but it works great and gets the grit off the paper. If you want a really nice, mirror finish, get some heavy-cut cleaner on a random-orbit polisher and keep going - the coaming will be super shiny when you're done, and you might find yourself getting carried away and going over the entire boat this way to make it all look completely new! If you do take that last step, I would be surprised if you could see any evidence of the repair at all when you're done, assuming your colour is a good match (black is usually quite easy).

    Hope that helps! Do it on a nice sunny day, and if you're at all like me, you might even find yourself enjoying it! :-o

     
  19. Astoriadave

    Astoriadave Paddler

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    Learn something new every day. A little research brought this up:

    http://www.westsystem.com/ss/polyester-over-epoxy/

    Works with WEST system resin.

    My experience has been with System Three resins, three types. System Three folks do not recommend direct application of polyester resins over their resins, last time I checked.
     
  20. Astoriadave

    Astoriadave Paddler

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    KayDubbya,

    Look at the dialog your question spawned! I learned a bunch of stuff, especially from Mark (henceforth to be known as Gelcoat King) and from Nootka. The rest of us benefitted from this as much as you did, I bet.

    Let us know how the repair turned out ...