Building RYD-16.9 Rocky - Hull 21

Discussion in 'Boatbuilding' started by John Theunissen, Aug 5, 2017.

  1. John Theunissen
    Joined: Aug 2017
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    Location: Melbourne, Australia

    John Theunissen Junior Member

    IMG_20171008_164129.jpg IMG_20171008_163938.jpg
    Greetings,
    With the help of my cousin, we spent the weekend sheathing both sides of the hull. We opted for the "dry" method, first pressing a coat of epoxy into the bare timber and covering the already sealed areas before carefully laying out the fibreglass cloth(trying to avoid creases). Wetting out the cloth took a lot of epoxy! Our favourite tool of choice for the initial coating and the saturation of the cloth was a plasterers plastic joint knife, worked a treat.
    Regards, John T.
     
  2. PAR
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Damn, you followed the instructions. Not the typical DIY approuch, but I approve and that's exactly the way I do it. The auto parts store as well as the big box stores, sell auto body filler applicators in various sizes. Buy a few packs. You'll end up cutting and shaping these puppies for fillets and odd areas that need a smear of goo, plus in spite of cured epoxy easily breaking off, the edges get torn up and not all of the epoxy always comes off. You can take a sharp razor and cut a new, clean edge on these, but the spreader gets a wee bit thicker each time you do. Eventually, this will be your tool of choice for spreading and applying goo. Looks good BTW . . .
     
  3. John Theunissen
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    John Theunissen Junior Member

    Thanks Paul, if it were not for reading and re-reading your "How to build this puppy and other stuff" as well as your very valuable "Tips-Tricks" material I reckon there may have been some monumental blunders along the way to this point. As it is, I'm really pleased with the results so far. The sheathing is a biaxial construction similar to the tape that has been used on the joints so it should be quite strong. Next challenge after finishing sheathing of the bottom plank will be filling the fibreglass weave with thickened epoxy, as per your guidance. I've bought some sanding filler powder which hopefully should be appropriate. Regards, John T.
     
  4. PAR
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    PAR Yacht Designer/Builder

    For novice builders I usually recommend System Three's "QuikFair" as a cosmetic filler. It's constantly smooth and easy to spread and sand. After you've smeared and smoothed things out, a final coating of neat epoxy to seal the surface is my next step, prior to paint prep.
     
  5. John Theunissen
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    Location: Melbourne, Australia

    John Theunissen Junior Member

    IMG_0627.PNG Thanks Paul,
    I've had a quick look and it doesn't look like that product is readily available in Australia. Here is a pic of the local Bote Cote product that looks like it is suited to the purpose. I'll use what I've got and see how it goes. The instructions mention that you need to mix it to a "soft whipped cream" state before applying.
    Regards, John T.
     
  6. PAR
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    PAR Yacht Designer/Builder

    Yeah, I forgot you're on the other end of our ball. Bote-Cote will be the usual source for most of your goo needs and they make a pretty good product too. I've never used that particular brand of filler, though I know a few that have and they've said it works well as a cosmetic filler. Getting a feel for the mixture viscosity is the main problem with mixing your own, after formulation of materials (the bag of powder). Vertical and overhead surfaces will want a slightly thicker mix, while horizontal mixes will live with a little runnier viscosities. You can also add a touch of silica to thicken it up (not much, as it works good in this regard) on vertical and overhead applications.

    Bote-Coat breaks down their filler selection into three basic categories, "lightweight sanding" (cosmetic), "fillet and glue" and "high strength" (light and heavy structural mixes". The light sanding stuff is for fairing, the light and heavy structural stuff if for gluing and under structural fillets. The two structural mixes are not easy to sand, though the light structural is much prefered in comparison to the heavy stuff, which is a ***** to sand. You'll use a fair bit of the light structural under the inside corner tapes, not a lot of the heavy stuff and bunch of the light weight stuff, depending on how anal you are, about things being smooth and straight.
     
  7. John Theunissen
    Joined: Aug 2017
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    Location: Melbourne, Australia

    John Theunissen Junior Member

    Thanks Paul, I've ordered some fumed silica powder for when I do the topsides where it's almost vertical. I saw one of your other posts where you mention a 4:1 mix with the filler so I'll be very sparing with the silica.
    Yes, I've been very satisfied with the Bote Cote products so far, their epoxy is excellent - almost no smell, low levels of toxic stuff, and easy to work with. Thanks again for your advice, much appreciated.
    Regards, John T.
     
  8. PAR
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    PAR Yacht Designer/Builder

    Don't take the ratios very seriously. Ratios are environment and application specific. In other words, a mix that worked good one day may not the next, if there's much difference in ambient temperature and humidity. The same is true with different surfaces, where some may suck up more or need a different viscosity, etc. You'll learn how to gauge things as you get practice with it.
     
  9. John Theunissen
    Joined: Aug 2017
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    Location: Melbourne, Australia

    John Theunissen Junior Member

    4126F5B8-79F7-4596-A83D-68D83FE3F502.jpeg Greetings,
    Some minor progress - completed the fibreglassing of the hull exterior and laminated what will become part of the keel plank (3 layers of 7mm Merbau garden edging timber to take the required shape). In the bow area the bend is quite severe so I’m still thinking about how best to do that section. I’ve also laminated the stock for the skeg - in the end I opted for Paul’s overlapping layers method rather than a strip planked approach, it certainly was much easier and I’m relatively confident that there won’t be any twisting along the length. I’m only going to get around to fairing the hull in mid-November (other family and work priorities) but still aiming for turn-over by Christmas.
    Regards, John T.
     
  10. PAR
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    PAR Yacht Designer/Builder

    You'll likely use the "lick 'em and stick 'em" approuch. This means you'll rip lengths of plywood to a width, try it maybe ripping it down some more, until it bends in easily, then you'll butter them up and stick them on. Conversely, you could just use biax in the forward areas. 2 layers of 12 ounce will stiffen her up pretty well, better with 3 layers.
     
  11. John Theunissen
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    John Theunissen Junior Member

    Hi Paul,
    Thanks for the tips. I was thinking about using the same 7mm thickness layers but half-sawing them through at regular intervals around the bend, thinking that the epoxy glue filling the saw “notches” would compensate for the loss of timber strength - I could try to stagger the saw cuts between laminations so that they don’t all occur at the same spot.
    Regards, John T.
     
  12. PAR
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    PAR Yacht Designer/Builder

    Don't "kerf" the plywood, Think of tis as cutting 'glass fabric across the grain and butting them together. It works, but you've lost the fiber integrity. Also when you apply the pieces, it helps to wet the convex side with water. I use a steam mop intended to clean grout lines on tile floors. My other half bought one and didn't like the tediousness of the process, so I stole it and have been making steam ever since. I like steam because it get things hot and moist (like me after a few beers), but this dries very quickly and you can move onto goo.
     
  13. John Theunissen
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    John Theunissen Junior Member

    Ahh, what would I do without your guidance Paul. Scratch my earlier idea, I’ll go for the thinner laminate approach and try the steam iron approach.
     
  14. PAR
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    PAR Yacht Designer/Builder

    There are "steamers" intended to clean tile floors. They make good, clean steam and do so quickly. Some of these are about 30 bucks, though the one I have is Italian made and cost about $150. I'm not sure how well the cheaper ones will do, but I'm fairly sure it boils down to watts and accessories. The multi funtion versions of these puppies, have higher wattages and larger container, so you get lots of steam, with a reserve and the tools to apply it broadly or with pinpoint accuracy. The tool I use the most looks like shop vac tool, but applies steam through little holes across about an 8" wide path. This works great on plywood and solid timber. On thicker stock I'll saturate the board first with the pencil point tip, then switch to the broad blade for really getting it wet and hot.

    [​IMG]

    This isn't the one I have, but is similar and priced lower too. If you steam a little, this puppy is a good investment, but on a single task, maybe not so much. Look around and you can save 20% - 30% over retail on this gadget.
     

  15. John Theunissen
    Joined: Aug 2017
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    Location: Melbourne, Australia

    John Theunissen Junior Member

    Thanks Paul, I’ve had a look at steamer product options here and there is a multipurpose 1800W product that is reasonably priced which I will purchase - you are right, it will come in handy for a variety of tasks. I’ve always wondered how one gets to have cockpit coaming with tight bends, this is probably how it’s done.
     
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