Peel's Coho build

Discussion in 'Boat and Accessory Building' started by Astoriadave, Feb 28, 2006.

  1. Peel

    Peel Paddler

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    I've got four on the hull now. I'll flip it over in the morning and do four more on the deck. There's probably enough in the quart that I could do 5 coats total. One of the methods mentioned in the Bristol manual is to do 3 coats wet-on-wet (like I've done) then after letting it cure for more than 24-hours, to do a light sanding and apply one more coat. After this final coat has cured, it can either be left as-is, or wet sanded to 1000, then buffed with rubbing compound.

    I don't think I'll go to that extreme, but will have enough LPU in the can to at least do the wet-on-dry coat if I choose to.

    I plan to launch it next weekend. :D
     
  2. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    You should come up next weekend and launch that boat at the Meet at the Beach gathering!

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  3. Mark_Schilling

    Mark_Schilling Paddler

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    Uh... isn't that two weekends from now?
     
  4. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    :oops:

    Yes, you're correct Mark. It's the last weekend of the month.

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  5. Peel

    Peel Paddler

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    Well, I was a little off in my estimation. I only had enough lpu to do three coats on the deck (to go with the four on the hull) before running out. Part of the problem was that the mix ratio for the Bristol Finish is 8:1 by volume (they don't publish the ratio by weight, so I couldn't go that route). Trying to keep that consistent is a bit of a problem when you are using a graduated container that is big enough to contain the mixed lpu, it's easy to be a little off on the 1-part of catalyst. I ran out of the catalyst with about a half-cup of urethane base left over. Thankfully the chemistry is tolerant enough to be this far out of equilibrium and still cure properly. (My ratio was closer to 7:1 instead of 8:1)

    My dilemma now is do I buy another Quart (at $50) for one more coat, or just go with the 3-coats on the deck, assuming that the deck won't take that much abuse.

    Thoughts?
     
  6. Peel

    Peel Paddler

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    Sound like fun, though I'll be over in Walla Walla on a winery tour that weekend :D . Would definately like to get my boat up there for the next event though.
     
  7. Batstar

    Batstar Paddler

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    Pete,

    I can’t speak for others who have used LPU in the past, but I managed to apply five coats to the deck and hull of my Tern 17 from one quart of System 3 WR-LPU. I actually purchased another quart, just in case, but will have it on hand when it comes time to refinish the boat. Since I have no experience with the solvent based Bristol product, I can only relate my thoughts to you when it comes to System 3.

    The result is a pretty hard finish and I’m quite comfortable with my decision particularly after returning from a recent trip. Received just a few minor but unavoidable scrapes on the hull’s LPU layers in return. I actually followed Dan’s advice after he completed the 5 finish coats on his tandem Osprey and I also diluted the LPU by 10% which likely helped extend its usage. The only drawback might be the additional sanding that I’ll be facing at the point in time when I decide to refinish it. That might be a few years off yet depending on how much future abuse the boat will encounter.

    If you ask me, 4 on the hull and 3 on the deck should be adequate. It almost sounds like the Bristol LPU has a higher viscosity resulting in thicker applied coats. How did the Bristol LPU go down? Did you find it easy to apply without leaving any significant traces of brush marks behind? I guess that’s what I found to be the most challenging aspect when applying the S3 LPU, particularly when the cross linker was added in the final two coats.

    Boat looks great btw! :cool:
     
  8. Peel

    Peel Paddler

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    The guy at the store did say that the Bristol goes on a little thicker than the System Three, so that would account for the fact that it didn't stretch quite as far (and of course the fact that I still have 4oz of Part A left in the can but no part B). It went down surprisingly easy. I applied it just like I did the epoxy fill coats - rolled it on, then tipped it with a foam brush. When I finished tipping it there were distinct brush marks, but by the time I was tipping off the next 2' section, the previous one was at an orange peel stage. By the time I had moved on to the third section, the first one was almost completely mirror-glossy smooth. Interestingly the Bristol folks have you add the cross linker to every coat - not just the final ones. Wonder if that makes for a harder final product.

    I think I'll leave it as is, and can always sand/apply another coat of two down the road if it looks like it's wearing too fast.

    Bart, you mention the additional sanding that you'll have to do when you refinish. It was my understanding that you didn't need to remove all of the lpu before recoating - just needed to sand out any scratches with 220 grit first. Am I mistaken?
     
  9. Peel

    Peel Paddler

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    :oops: Oops, sorry Art. I started to write Batstar, then went to change it to Art, but guess I didn't do a very good job of that. :oops:
     
  10. Batstar

    Batstar Paddler

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    I guess it all depends on the extent of damage but you’re probably right. Using a cabinet scraper might make the task a bit easier. Some of the gouges on Dan’s Osprey looked severe enough to warrant him removing as much of the LPU as possible. I believe that he even went one step further and rolled on a couple of layers of epoxy afterwards. I would likely focus more attention on the deck than the hull since it will be exposed for all to see and figure that a bit more work sanding/scraping will ultimately yield better cosmetic results as it did when Dan refinished his Osprey. From what I understand, the epoxy is harder but not nearly as tough to remove as LPU.
     
  11. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    Next time I refinish the LPU on my boats I won't be removing the old LPU to the extent that I did with my double. A throrough sanding of the surface followed by a re-application of LPU will probably be quite enough to get a nice new finish.

    The only place I'd sand the LPU right off is anywhere that there might be deep damage -- and then I'd only do those specific spots.

    I didn't remove all the LPU from the hull of my double -- I surface sanded and then applied a couple skim coats of epoxy before re-applying the LPU -- it worked out fine.

    fwiw: in retrospect, I did WAY more work on my double than was truly necessary.

    *****
     
  12. Peel

    Peel Paddler

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    I'm in the home stretch... the final moments of building my Coho. I installed the soft padeyes and hatch straps tonight using clear GE Silicone II that contained a bio-agent that prevents mildew from forming in any crevices of the silicone. Tomorrow morning I'll rig the deck and (if the weather doesn't totaly suck) launch it for a paddle around one of the local lakes. I haven't decided where to go yet. I might shoot for the Arboretum, through the Montlake Cut and around Lake Union. Again, it depends on the weather.

    Here are some shots from this last week after the LPU cured.

    Glossy. Glossy, Glossy 8)
    [​IMG]
    [​IMG]

    Here's one of the soft padeyes with the silicone applied, ready to feed up through the slot in the deck
    [​IMG]

    Everything in place, and clamped on
    [​IMG]
     
  13. jurgenk

    jurgenk Paddler

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    The art inlay looks amazing, as does the boat Pete.
     
  14. Astoriadave

    Astoriadave Paddler

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    Looking real fine, Peel. Let's hope the blackbirds along the lakeshore don't divebomb that art! :wink:
     
  15. chodups

    chodups Paddler

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    Launch at the museum? I'd love to see it in person and have the day to paddle. This morning is kind of wet but.........maybe this afternoon?
     
  16. Dave_Barrie

    Dave_Barrie Paddler

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    Looks awesome!
     
  17. Peel

    Peel Paddler

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    Well, things didn't go quite as planned this weekend. Too many other projects that I've been ignoring while building my kayak had finally got the best of me, and I wasn't able to launch on Saturday as planned.

    I did get it out of the attic on Sunday though.

    After removing a double-hung window, my brother and I passed it out to my friend John who was standing on a ladder on my back deck. Then I ran down to the deck, and took it from him, and we lowered it to the ground, and finally carried in down my front steps (all 23 of them) to my garage.

    Coming out the window
    [​IMG]

    [​IMG]

    In the Back Yard
    [​IMG]

    Down the Steps
    [​IMG]
     
  18. Batstar

    Batstar Paddler

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    Luna looks incredible Pete! :cool: Can’t wait to see the look on your face when you get her out on the water.

    Well Done! :)
     
  19. DarrenM

    DarrenM Paddler

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    Awesome! 8)
     
  20. Astoriadave

    Astoriadave Paddler

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    Yowsa! Loved the birthing shot as it exited the upstairs window.