Finishing a pygmy kayak

Discussion in 'Boat and Accessory Building' started by meredith, May 1, 2016.

  1. meredith

    meredith Paddler

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    Hi All, I'm a first time builder and am near completing a pygmy stitch and glue boat (with systems three epoxy). I'm looking for advice on choosing a spar urethane for the final finish, as well as any tips on application. I don't have a sprayer but have a fairly well ventilated work space.
    Also, I've seen from some peoples posts, that they did a final sand and epoxy application before sanding again and finishing. I do have some places (mainly on the deck) where you can see the texture of the fiber glass cloth (not the actual cloth just the grid texture). Would another epoxy coat be advisable or just overkill. Additionally, is there a recommendation on how long to wait from the last epoxy work before sanding and finishing?
    Any opinions or advice would be welcome.

    Thanks,
    Meredith
     
  2. Kayak Jim

    Kayak Jim Paddler

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    On the deck of my CLC kayak I used Pettit Z-Spar Captain's Varnish, applied with a foam brush. It provided a great finish that has stood up well. I used yellow Epifanes one part urethane marine paint for the hull and really like the two-tone look.

    If you can see the weave pattern of the glass, it means you have not sanded enough. The varnish will not fill this. I probably spent as much time sanding and finishing as I did building the boat. If you sand some more and start to see glass fibres, this means you need more epoxy.

    You can check the instructions on your brand of epoxy but generally if it has cured enough to sand, it has cured enough to apply the finish. I like to use the fingernail test- if you can see any impression after pressing your fingernail into the epoxy, it hasn't cured enough. You'll know too when you start sanding, the epoxy will quickly clog the sandpaper if it hasn't fully cured.
     
  3. JohnAbercrombie

    JohnAbercrombie Paddler

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    This advice is correct, IMO, but....
    It's difficult to see the difference between 'weave still showing even with a lot of epoxy on the glass' and 'weave still showing because I haven't added enough fill coats' unless you have a bit of experience.
    You don't want to sand into the glass, so I'd recommend another fill coat of epoxy if you have any doubts.

    How many fill coats have you added so far?

    Do you want a smooth 'mirror' gloss finish on the deck? (You do want the bottom to be smooth, and it's easier to keep the deck clean if it is smooth. OTOH, epoxy is expensive and adds a little bit of weight with every application.)
     
  4. meredith

    meredith Paddler

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    Thanks for the suggestions. For both the hull and deck, the wood was saturated first, glass cloth painted on, then 2 fill coats. The hull is quite clear and smooth, just a few runs that happened later. The deck is mostly clear. The spots where you can see the texture of the glass tend to be towards the sides. It would be nice to have a perfect finished product. But, you're right epoxy can be pricey and heavy and I would avoid another round of sanding and epoxying if it was unnecessary, and the finishing spar coats would be sufficient.
     
  5. JohnAbercrombie

    JohnAbercrombie Paddler

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    As Jim said, you can't depend on the varnish to fill anything except fine scratches. The varnish just gives UV protection to the epoxy.
    If you want a smooth gloss finish, you need to (wet) sand the epoxy to a smooth 'satin' finish with no glossy spots showing before you apply varnish.

    One good thing about the 'wood look' (clear finish over plywood or strips) is that the eye is mesmerized by the wood grain, and people tend to overlook small flaws in the varnish. (With a painted finish, every little imperfection is noticed.)

    I'm sure your boat will look good no matter how you proceed from this point!
     
  6. meredith

    meredith Paddler

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    Thanks for the info, that helps quite a bit. I do plan to thoroughly sand, and likely wet sand, before varnishing. I suppose, if I see cloth show through during sanding, I'll stop then and deal with epoxy. Any opinions about spar urethanes? I know pygmy recommends system three's spar urethane or Zspar flagship varnish, and CLC recommends Interlux. I have not worked with any of these before. Thanks
     
  7. JohnAbercrombie

    JohnAbercrombie Paddler

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    I don't do much varnishing these days, but I'd be confident using either ZSpar (Pettit) or Interlux products.
     
  8. Astoriadave

    Astoriadave Paddler

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    Late to the game, Meredith, and agree with most of what has been said. However, I would lean strongly towards another fill coat. In my experience with S3 resins, two fill coats do not give sufficient coverage. I would use 80 grit to take the gloss off, and then roll on another coat of resin.

    Follow that with a cabinet scraper to take off the runs and major imperfections. Only then should you attack it with 100 grit wet or dry paper, I have successfully sanded cured S3 resins, done wet, far before I could resand using 80 grit, dry. Shortest wait time was probably 2 days. ROS on the panels, sanding block ONLY by hand, on the seams and panel breaks.

    And, do not be surprised if you find a touch up coat is needed after the 100 grit.

    It is critically important to avoid sanding into the glass, hence the early transition to wet sanding, which gives a uniform matte surface pretty quickly. I usually use a ROS, with a slow stream of clear tap water handy to flush the sanding residue away.

    I have never been in a rush to lay rhe varnish on. But when the surface is able to take wet sanding, that is usually the best indication it is ready. A final wash of fhe sanded surface with soap and water, followed by a rinse with clear tap water, toweled off, will get you to ready to varnish pretty quickly.
     
  9. meredith

    meredith Paddler

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    Hi Dave and all,

    Just wanted to say thanks for all the advice and info. I've now completed all the steps except for final epoxy and finishing. I'm going to take the advice and sand and epoxy, one more fill coat, over the whole boat this weekend. Wait. Then sand and finish. Any other opinions or suggestions, are still welcome.

    Thanks again,
    Meredith
     
  10. Roy222

    Roy222 Paddler

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    I used catalyzed water based urethane. It has held up well over time. I applied 5 coats and did not rub it out. The gloss was very good, but not boat show good. Overall, it was worth the extra cost and time. This finish is more scratch resistant then oil base varnish.
    Application is tricky, but you will get a lot of free advise on this blog.


    Roy
     
  11. Mac50L

    Mac50L Paddler

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    Which is why I always ask, why glass everything? It just isn't necessary and saves money and weight by not doing it and the kayak is still strong enough without the glass. Also a pain repairing with torn up glass if scraping over rocks.
     
  12. JohnAbercrombie

    JohnAbercrombie Paddler

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    I don't think you'll find many folks who will agree with this, if they paddle amidst rocks and barnacles. Plywood without epoxy and glass (protected only by paint) will get torn up quickly, and then water will penetrate the wood. How do you do a repair to this? Even after the boat is dried out (after trying to get the salt out with fresh water rinsing), the paint will need removing to let the repair adhere.

    You can test this yourself by dragging some weighted samples across a concrete slab, or just using a sander on two pieces of plywood - one only painted/varnished, the other with epoxy and glass and paint/varnish.

    If you are going to epoxy the plywood, you might as well add a layer of glass as it is an effective gauge for the thickness of the epoxy coating.

    Plywood is quite stiff, but glass sheathing does increase the stiffness even further.

    By the time you have added fillets (on the inside) and glass over the seams (on both sides), it doesn't take a great deal more to glass the whole surface - especially if the S&G kayak is a more interesting/complex shape with a lot of panels.

    I do agree that it is cheaper not to use glass and epoxy when building a kayak.
    For a prototype or 'throwaway' S&G boat, I'd consider using cheap plywood and narrow glass tape.

    ???
    "with" or "the" ?
    Epoxy/glass doesn't 'tear up' - separate from the wood - if it was properly bonded.

    What do you use to repair un-epoxied and un-glassed S&G kayaks?
    How do you bond the panels together when building S&G?
    Do you use a varnish finish over plywood?
     
  13. Mac50L

    Mac50L Paddler

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    I didn't say I didn't use epoxy, which I do and I use glass on the keel, chine and deck/side join. Glassing all over as well as epoxy tends to use 3 times as much epoxy which is heavy and expensive.

    Admittedly I might not have much experience as my oldest kayak, used a month ago by the grandkids, is only 33 years old. The most damaging environment I suspect was circumnavigating Vanua Levu, Fiji in my double, which being heavily loaded was often dragged over coral. A bit of work need on return, reglassing/epoxying the keel. That kayak is only 20+ years old.

    The kayak my partner paddles, she built in 1997, epoxied and varnished. She recently sanded it down and painted it. The UV here doesn't do varnish much good no matter how UV resistant it is. Coming ashore she always runs it up on gravel beaches.

    The oldest craft I have is the plywood dinghy my father built for us as kids, must be about 60 years old, no epoxy, no glass. It does need a repaint and then I'll use it again for setting a founder net over at the bay. Yes, paint chipped and worn and most probably salt water impregnated so it will probably only last another 100 years if looked after i.e. not left out in the weather full time for the rest of its life.