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Thread: First questions from a self build virgin

  1. #1

    Default First questions from a self build virgin

    Evening all

    Firstly, why am I doing this? Only because my closed cockpit kayak is hard work on the canals and lakes round here for distance and I'd like to make something.

    Secondly, please confirm my understanding is correct for the build process (simplified as I do simple really well)
    - Buy plans and ply and other stuff
    - Cut to shape
    - Stitch together (using dowels, great tip)
    - Tape and epoxy seams on the inside
    - Remove stitches
    - Finish tape on the inside
    - Tape and epoxy the seams on the outside
    - Paint
    - Paddle

    Question: Is the external tape and epoxy necessary? (yes, any small gaps will need to be filled) Surely the inside tape and epoxy will stop it falling apart?

    Question: Why do some builders coat the outside (or inside) in epoxy or fibreglass and epoxy?
    Surely a coat of a good quality paint/varnish is enough to protect the wood?
    For me, the natural look of wood is best, but I seek advice from the experts...

    And the last question for 10 points

    My search/sort/filter/choose/hope has resulted in this one : http://www.jemwatercraft.com/proddet...uringPirogueTV

    What are your thoughts please? (solo paddler, flat water and minimal equipment carried afloat <15kg).

    Thanks
    Paul
    Looking for the end of the rainbow

  2. #2
    Join Date
    Sep 2014
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    Cumbria
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    Yes the inside layer of glass and epoxy will hold it, you'll need to fill the external joints with thickened epoxy.

    When I built mine, I secured the joints with small dabs of superglue all the way along, then removed the stitching and laid in the epoxy fillet and glass tape in one piece. The superglue was enough to hold the boat in shape while the epoxy was applied.

    A layer of glass/epoxy on the outside makes the whole thing tougher but yes, you could simply varnish it. Or, as many people do, fibreglass sheathe the whole outside rather than just tape. Once that's done, a few filler coats of epoxy to fill in the texture, a coat of varnish and you would have to look very closely to see the fibreglass weave. the fibreglass goes totally transparent.

    My stich and tape ply boat is fibreglass sheathed inside and out.



    My build blogg is still up but the pictures could disappear at any time due to photobucket.
    http://www.songofthepaddle.co.uk/for...t=peterborough

    A pirogue would probably be ok on canals, you may suffer from lack of freeboard and overall manouverability in other situations. From the JEM catalogue, I like the look of their Trapper 15 canoe. Probably not QUITE as quick as a pirogue but a lot more versatile. Also less likely to swamp in lake situations if the wind and waves get up (look at the heights). I also like the look of their sasquatch 14 which of the ones they list, Is what I'd chose for a solo flatwater canoe.

    Don't worry too much about claimed "tippiness" that's something you get over in the first few outings.
    "I'm not getting in a boat which is DESIGNED to go upside down."

  3. #3
    Join Date
    May 2007
    Location
    Redcar on the North East Coast
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    484

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    The Gem Trapper is a superb boat, I built one for my son and he loves it.

  4. #4

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    Thanks Stinkwheel, I have read your thread, looks a nice boat.

    Cheers Bob

    When I get to a real computer, will have a look at the others suggested.

    Given the weather here in Wales today, might need a boat at home...

    Paul
    Looking for the end of the rainbow

  5. #5

    Default

    Right, proper computer and a decision has been made.
    A Trapper 15-35 will be built...
    All I need now is a space to do it!
    Thanks for your help
    Paul
    Looking for the end of the rainbow

  6. #6
    Join Date
    May 2007
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    Redcar on the North East Coast
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    Check your inbox Paul.

  7. #7

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    Thanks Bob
    Looking for the end of the rainbow

  8. #8

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    Hi there
    Plans have been studied intently, supplies researched and all I need now is a place to build it.
    The sheets maybe marked out and cut in my lounge... (advantage of living away from home during the week!)

    A snowy Sunday question for the open canoe massive; The plans calls a butt joint in the panels, with glass and epoxy both inside and out.
    I am intending to leave the outside au natural, naked apart from a couple of coats of varnish.

    Will a butt joint be strong enough with just a tape and epoxy on the inside?
    Or should I scarfe the joint instead of butt join?

    Enjoy the weather :-)
    Paul
    Looking for the end of the rainbow

  9. #9
    Join Date
    Nov 2007
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    cambs
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    Not any sort of expert on this type of construction but here are my thoughts

    If I was only putting glass on one side, I'd want it on the outside: The pulling force on the outside from bending the panel would then be contained.

    When glass is applied properly it becomes invisible. The only thing you would see is a small ridge where the glass begins and ends. This could be feathered by sanding so you can do both sides.

    A long scarf would probably be ok - but I think you'd need about 1:8 - 1:10 - and unless the glue joint is very good, it could well open up on bending the panel.

    Sam

  10. #10
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    Sep 2014
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    As above, I'd do both sides and not worry about it, by the time you've applied a few coats of epoxy/varnish to the outside, the texture of the glass practically disappears and it's totally colourless. You could use very fine weave cloth to start with too.

    Pretty sure our scarf joints were 5:1 and were glued with polyurethane adhesive clamped down firmly to set. They held very well. I think the wood would have split before the joint let go. There isn't a huge amount of bend in the wood at that point either.

    Of course, we did both. Scarfed AND glassed both sides. Which would be the "gold standard" way forwards. Certainly not wrong to scarf them if the plans allow enough extra length on the sheet to do so.
    "I'm not getting in a boat which is DESIGNED to go upside down."

  11. #11
    Join Date
    May 2007
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    Redcar on the North East Coast
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    Recommended scarf length is 1:7 with an epoxy glue. I used butt joints with butt straps, not pretty but the scarfing looked as though it was harder to do. There is a post on this site that gives a good insight into making scarfs and getting them in the correct place according to the plans. Be aware of Stinkwheels note about having enough length on the panels to create a scarf. Good luck with the build.

  12. #12

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    Thanks for the inputs.
    Due to the weather conditions yesterday, all materials (and tools) have been ordered, total cost of about 250 Great British pounds
    The ply comes in 250cm lengths, I think it's a little more than British stuff. So I have adequate length to allow for a 1:7 or greater scarfe. (4mm ply x 7 = 28mm, so a little over an inch).
    Going to have to make it now!
    Paul
    Looking for the end of the rainbow

  13. #13
    Join Date
    Dec 2017
    Location
    Belgium, Gent
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    Succes Paul! The Trapper looks much nicer than the pirogue.
    @Stinkwheel: superb looking Peterborough Oh, and I've been through your thread on the build for a second time

  14. #14

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    Well
    After two evenings and a Saturday morning, I've converted four sheets of ply into 16 strips of ply and made a small bag of sawdust.
    Tomorrow is prepare to join them together into eight really long bendy bits of plywood.
    Only put one small cut into the kitchen table....
    Sometimes I am pleased the weather is bad
    Cheers
    Paul
    Looking for the end of the rainbow

  15. #15

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    Build update...

    After a pile of stuff arriving over Christmas, it's time to start again
    Found a bit of an error with one scarfe joint
    Spent today cutting 25mm off the ends of the other panels to match...
    Primed the all the cut edges with epoxy and opened a beer.
    'tis enough for one day.

    Paul

    Pictures to follow once I have something decent to show.
    Last edited by sonflowerinwales; 6th-February-2018 at 05:54 PM. Reason: 'kin autocorrect
    Looking for the end of the rainbow

  16. #16
    Join Date
    May 2007
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    Redcar on the North East Coast
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    How's the build going Paul?

  17. #17

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    Hi there
    Quick update as there is little progress i.e. none... This works lark gets in the way of your own project
    Had a practice using thickened epoxy to fill and join some offcuts, then reinforced with glass fibre and normal resin. All good so far.
    Next free weekend is in April (!) hope to have a garage by then too.
    Cheers
    Paul
    Looking for the end of the rainbow

  18. #18

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    Evening all
    Woohoo, some progress has been made!
    After running a sailing course for the last two months, I have some free time.
    Now converted 16 short bendy planks into 8 long bendy planks. (note the use of a light load to keep them flat while setting!)
    Negotiated a garage space this morning, so next weekend should see rapid progress.
    Cheers
    Paul

    Looking for the end of the rainbow

  19. #19

    Default

    There was some earlier discussion about the necessity of taping the seams both on the inside and outside of the hull. Do both. Here's why.

    Glass is stronger under tension than compression which means you would be okay with only glassing the inside if forces were to only be applied from the outside. However, in the case where the ends of a boat are pressured whilst the centre is unsupported (such as where the stern is on land and the bow is floating) forces will want to pull the boat apart at the centre. As that force cycles (as might happen in waves) incremental outward pressures will want to force the boat apart at the seams and the absence of external glass will mean your hull relies on the weaker compression characteristics of glass and is more likely to fatigue and split. I'm not suggesting that your hull WILL fail. I am suggesting that there is a significantly greater chance of it doing so if not taped on the outside.

    As for applying epoxy to the entire hull, you will find that it provides a somewhat better hydrophobic seal than if you rely on varnish alone, particularly if you thin the first coat and let it penetrate the wood. Varnish with UV inhibitors will still be required however.

    Best of luck with it,
    T
    Trevor Paetkau
    Ashes Still Water Boats
    Canoe Plans | Custom Boats

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