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Thread: Should I ease lapstrake edges for painted finish?

  1. #1
    Join Date
    Mar 2022
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    Jamestown, RI. USA
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    Default Should I ease lapstrake edges for painted finish?

    I'm in the midst of building a Herrreshoff 17' rowboat, getting ready to do the sheer planks. It won't be long after that when it will be time to paint the exterior.

    I am doing glued lapstrake planking with 6mm plywood. As I've cut the planks out I pre-finished the interior side with a saturation coat of epoxy and sanded them to 120. The bottom and garboard will be sheathed in 6oz glass inside and out. The remaining planks will be epoxy saturated only painted with two-part polyurethane.

    Remembering the old adage "round all corners, ease all edges," I'm wondering if I should ease that outer corner of the planks to get the paint to last better.

    Any thoughts on the matter?

    Here are a couple shots of the build, when lining off the planking and double-checking the sheer after the first four planks.
    IMG_4998.jpg
    IMG_5478.jpg

    Thanks -- Tony

  2. #2
    Join Date
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    Default Re: Should I ease lapstrake edges for painted finish?

    Welcome to the Forum!
    I've built quite a few glued lapstrake boats and always eased the edges just a wee bit.
    It doesn't take much to ease an edge for paint to adhere better just a little swipe with a piece of sandpaper.
    I think it even more important since it's plywood which could easily splinter if left sharp.
    I was born on a wooden boat that I built myself.
    Skiing is the next best thing to having wings.

  3. #3
    Join Date
    May 2015
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    Guerilla Bay, NSW, Australia
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    Default Re: Should I ease lapstrake edges for painted finish?

    I'd suggest - it depends.......................
    Do you want the boat to look like a traditional timber pin & rove clinker build and what would the edges have looked like after a traditional construction?
    Or, are you happy with a look which is slightly (very slightly) different to a traditional look?

    I am building my 3rd glued clinker boat, I do not round the edges of the planks, but I do make sure that the ply edges are well sealed - I use water thin 2-part sealant that I slosh (technical term) on till the ply stops absorbing - allow to dry for 2-3 days & then sand, then I paint with enamel.

    Good Luck Neil

  4. #4
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    Default Re: Should I ease lapstrake edges for painted finish?

    Round ‘em. Knick off the hard edges at the minimum. No sharp edges on little boats is a good rule. Not a bullnose, but as Rich said, ease them. Paint will stick and they’ll feel good in hand.
    Quote Originally Posted by James McMullen View Post
    Yeadon is right, of course.

  5. #5
    Join Date
    Mar 2019
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    Rushworth, Australia
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    Default Re: Should I ease lapstrake edges for painted finish?

    I vote Ease em. Paint will stick better and won’t get knocked off as easy.

  6. #6
    Join Date
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    Vancouver, BC
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    Default Re: Should I ease lapstrake edges for painted finish?

    My vote is just a slight easing with sandpaper. That's what I've done on my wherry build and the paint appears to adhere well.

  7. #7
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    Apr 2010
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    Fairfield, CA
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    Default

    A vote for fairly generous easing. They are going to get dinged, you do not want water getting into plywood.

  8. #8
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    Default Re: Should I ease lapstrake edges for painted finish?

    We used to glue on a strip of hardwood usually mahogany, the thickness of the plywood x about 3/8" this was faired again with a rebate plane and skimmed off to exactly the planking thickness with a block plane. That protected the end grain and allowed you to plane a wee chamfer to hold finish, it disappeared after the first coat of paint.

  9. #9
    Join Date
    Apr 2015
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    Default Re: Should I ease lapstrake edges for painted finish?

    I'm with the majority here on easing edges. It's a boat...anything sharp will get bumped eventually and break that finish.

  10. #10
    Join Date
    Mar 2022
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    Jamestown, RI. USA
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    Default Re: Should I ease lapstrake edges for painted finish?

    Thanks, everyone. Seems like we're pretty much in agreement on doing some easing. I'll proceed along those lines.

    Learned quickly about that from the ergonomic view on the interior of my first boat, a 28' single-chine plywood cruising boat. Sharp edges are a real pain in a seaway.

  11. #11
    Join Date
    Jan 2008
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    903

    Default Re: Should I ease lapstrake edges for painted finish?

    I ease edges, and put a small fillet down in the corner of the lap. In fact, I fillet ALL epoxy seams. The paint film lasts much longer with no hard inside corners to crack.

  12. #12
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    Dec 2003
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    Default Re: Should I ease lapstrake edges for painted finish?

    Quote Originally Posted by jim_cricket View Post
    I ease edges, and put a small fillet down in the corner of the lap. In fact, I fillet ALL epoxy seams. The paint film lasts much longer with no hard inside corners to crack.
    Strongly agree. Not so heavy a fillet that it's visible, but even a tiny one makes a big difference to paint adhesion, and even strength.

    And yes, ease those sharp edges - for two reasons. First, leaving them sharp leaves them vulnerable. They'll get rounded over in use anyway, best to beat nature to the punch and get some paint on. Second - because of the surface tension/capillary action of the wet paint film... it will want to migrate away from any sharp edge. That leaves the corner poorly protected by the paint . The paint performs much better covering even a slightly eased edge.
    David G
    Harbor Woodworks
    https://www.facebook.com/HarborWoodworks/

    "It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

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