Newbie - Hello Everyone

Discussion in 'Boat and Accessory Building' started by rookiebuilder, May 30, 2009.

  1. Roy222

    Roy222 Paddler

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    epoxy

    The more epoxy you buy the more you will use and the heaver the boat will be. Try to resist tapping all the seams. That 9 oz. tape really likes the epoxy.
    For strength and weight a consistent and small fillet will help reduce weight and reduce stress risers. If you smash your boat on a rock a thick fillet will dump stress on thinned out fillet and the boat might crack open.
    Please post a photo of your NC cut panels.
    Roy
     
  2. rookiebuilder

    rookiebuilder Paddler

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    Re: epoxy

    I learned to fiberglass by helping friends build their airplanes. I have studied composites extensively and have some hands-on experience. So I am pretty sure I will build a light kayak. :wink:

    I plan to get photos of the panels being cut. Yes, I will post a bunch of photos. I will try to get enough photos of the entire build to make a journal like Maddie's and Dan's.
     
  3. rookiebuilder

    rookiebuilder Paddler

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    epoxy

    I just talked to tech support at a company in Florida called US Composites. They have a line of epoxies that are half the price of System Three. When I asked about this difference, he said it is because of their distribution system. They only sell direct - there are no distributors. So there are fewer markups in the distribution which makes it similar to buying it wholesale.

    They have a low viscosity epoxy that should compare favorably to SilverTip for $120 / 3gal (vs. $243 / 3gal for SilverTip). I am seriously considering giving this a try.

    Does anybody have any experience with this stuff?
     
  4. woodensoul

    woodensoul Paddler

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    You don't just want low viscosity, but also make sure that it will stay clear without going milky over a few years. Lot's of folks here use Silver Tip because it does that well. I am still using West 207 as this have a proven track record. Personnaly I also wouldn't use a system that did not have metering pumps, as life is just too short to mess with any other method when wetting out cloth. (just a personal preference guys :wink: ) So push them on some references for clear coat applications...

    ws
     
  5. Astoriadave

    Astoriadave Paddler

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    rookie, there are many variables which distinguish epoxy formulations. The choice you make can have unexpected consequences, including unusually low ability to wet glass, high tendency to form amine blush, etc.

    I'm a System Three user of many years because I know and trust their formulations. I order mine direct, and have been very satisfied. The Silvertip does not blush. I think it may be a "second generation" polyamide-based resin, instead of a polyamine-based one.

    One good (online) resource is the S3 "Epoxy Book", which describes some of the differences among their formulations. WEST Systems also has an excellent online resource on theirs.

    More than "marketing" affects the cost and value of a brand. I know nothing about the lower-cost alternative you have found. Before selecting it, I would definitely get some beta from users. YMMV
     
  6. rookiebuilder

    rookiebuilder Paddler

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    Both great comments! I have been learning more about epoxy since my last post and have found what you say to be accurate. I have more research to do, including another call to the tech to get more answers before I buy. :wink: :cool :wink:
     
  7. rookiebuilder

    rookiebuilder Paddler

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    More Questions:

    The Pygmy website states:
    Is this accurate? I've seen a few other places that give a similar number.

    I had planned on building my kayak on Whidbey Island, WA (I live in California) when I visit my mom.

    Is it reasonable to expect to be able to build it during a 3 week visit? Or is the 50-70 hours something that will be spread out over more time than that?
     
  8. Tootsall

    Tootsall Paddler

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    It is strongly a function of how quickly your epoxy cures up (which is a function of temperature/humidity). I began my build April 1 and I'm just at the point of applying varnish now: I've worked on it virtually every day but that old song "Hurry up and wait" keeps playing over and over.

    Whether the 70-80 hour worktime estimate is accurate or not is a function of your skill level and (probably more importantly) experience. I haven't made any effort to keep track of the hours so ~~~~~~~

    There are things I've done that wasted time, circumstances that couldn't be avoided (warped panels...a function of very low humidity "here"), perhaps a couple of things that I did do that saved some "envelope time"... so it's a mixed bag. But to cut 9, 10 weeks down to 3? Nope. I know that a friend (from Germany) wanted me to hold the build off until we meet at the lake this summer for 3 weeks: I had to tell him that it would be impossible to do a build in that length of time and it turns out I was so right.
     
  9. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    No.

    *****
     
  10. Tootsall

    Tootsall Paddler

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    Oh, you may wonder about the difference in working time from the 50-70 hours to 80-90? I believe that's largely a function of whether or not you install hatches/bulkheads and put your footbrace tracks in with epoxy or just drill holes through the hull. Also deck gear: they ask that you drill the holes and then seal them with epoxy...and that requires ANOTHER 12-24 hours to cure before installing the screws. I also don't believe that the shorter time includes varnish: if you go that route you'll find that you spend 1-2 hours wet-sanding and coating the hull and then 24 hours waiting for it to dry to the point where you can wet-sand and apply the 2nd (and 3rd and...) coats on.
     
  11. Astoriadave

    Astoriadave Paddler

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    Those build times are very optimistic, for sure. More important is that you must wait for several hours (minimum; overnight waits are far more typical) between resin applications before you can resume work. I've built two of their kits, and a 20ft power boat (plywood; and not stitch and glue). Even so, I doubt I could match those times. Finally, I would never "rush" such a project -- too many chances for error and I would not enjoy it.
     
  12. woodensoul

    woodensoul Paddler

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    Hi Rookie,
    Here's a method you can use to get the number of elapsed days. I am a strip builder so I can not give you a good number on this. But the issue which makes these project stretch out in elapsed time is the same. Fundamentally every time you do anything with epoxy, tools go down for 24 hours. For some tasks like waiting for cloth to dry out before you can sand it, it will be longer. You might thing that a small epoxy job won't require you to stop, but often it involves having the boat oriented in a certain manner in order for it to dry, or dust that gets stirred up while its drying is undesirable, or... Now a lot of the folks on this site may put more detailing into a boat than you think you want, so you might subtract a few tasks from your list. So take the number of drying days and add a week (?) to it for orientation and getting major pieces setup and you probably have a number that's in the ball park... Since your an ME we will expect a project schedule out of this and periodic reporting as to how you are meeting your milestones... :wink:

    ws
     
  13. rookiebuilder

    rookiebuilder Paddler

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    :lol: :lol: You just gave one of the better laughs I've had in a while. :lol: :lol:

    Yes, I was literally laughing out loud. :wink: Thanks for the guide to figuring out the elapsed time. Since I am not buying a kit but making my own instead, I'm guessing that too should add some time for collecting all the stuff. It's looking like it will take more than one visit to Whidbey Island in order to complete it (I'm not really excited about building it in CA and carting up to WA). That will certainly please my mom....

    Oh and don't forget, building a kayak is supposed to be fun. So maybe you shouldn't get too invested in getting those reports. :cool
     
  14. Astoriadave

    Astoriadave Paddler

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    Ooof! An engineer!!?? My sympathies to your Mom ... :wink: :wink:

    Seriously, it ought to be a piece of cake for an ME to parallel process high-turbo get 'er done!
     
  15. rookiebuilder

    rookiebuilder Paddler

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    I guess the honeymoon is over... :shock: I must have posted enough that I'm no longer treated as a newbie. :wink: :wink: No more kid gloves.... :roll:

    Well, okay, now that I know what I'm in for... :? :? :cool
     
  16. Astoriadave

    Astoriadave Paddler

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    'S Okay, man. I'm a chemist, so I'm also a big target! Flail away!
     
  17. rookiebuilder

    rookiebuilder Paddler

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    I spent a lot of time this weekend with my computer. :roll: I went through the entire process of re-laying out the panels. Since it was July of 1998 that I originally wrote the program to 'unwrap' the 3D panels to a flat 2D shape, it took some time trying to remember what I did back then. :shock:

    When I finally coaxed some memories from the nether regions of my noggin, I remembered that I had originally (11 yrs ago) changed the length from Nick's 17' to 16' (so I would only have to make one joint in the plywood). I had since changed it again to 17.5' in length. But when I increased the length, I didn't recalculate the panel shapes, I just scaled them up in 'X' but not 'Y'. At the time I had rationalized the distortion would be minimal. :?

    So in getting ready to finalize the design to take it to the CNC router, I discovered a minor aberration in the shape of the gunwale and that did it. I had to tweak the geometry and recalculate the panel shapes. There was as much as 1/4" difference in the sweeping curve of the side panels. :oops: Probably just enough to be a real PITA.

    I also changed my mind about using 3'x7' door skins and have subsequently rearranged the panels to use four 4'x8' sheet of plywood with the bottom panels being of a slightly thicker sheet (shown with tan background instead of gray).

    This is what it looks like so far:
    [​IMG]

    I have some room left so I'm planning on adding formers and jigs (if I can plan that well). :wink: I've already added doublers for the hatches and other areas.

    I'm also considering a 'keyhole' shaped cockpit cutout. Does anyone have comments about that? Pros? Cons?
     
  18. Astoriadave

    Astoriadave Paddler

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    Wow. Quite the layout. My main reservation/recommendation would be to eliminate the pickle-fork joins. In 4 mm okume ply, glass tape-reinforced butt joints (way Pygmy does this) are plenty strong, easier to make, and consume far less plywood. Could be you might be able to dial back to three sheets of plywood.

    Also, the coaming layout could be changed to use less plywood.
     
  19. rookiebuilder

    rookiebuilder Paddler

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    The reason I used the pickle-fork joints is to aid in the alignment of the pieces, not strength (with the fiberglass on both inside and outside, strength would be the same either way). It is easier to keep the strips straight with the overlap in the joint. Also, since I'm getting this CNC routed, "easier to make" seems moot.

    Yeah, maybe so. Though as I said, I plan to add some fixturing and forms to use up the extra real estate.

    If I really wanted to use minimum plywood, I could have stayed with the 16' OAL mod I originally made. With the recent addition of CNC routing, my priorities have shifted to simplifying the building process. If I need to make fixtures, templates, forms or other tooling, I may as well have the CNC router cut them out for me. Although it does take a lot of planning and going through the building process to figure out how I want to do it.

    This is something I do on a regular basis (y'know being an ME and all... :wink: ). So even if I don't provide regular progress reports and milestone scheduling, I'll still fall back on some of those ME habits.... :roll: :wink: :cool
     
  20. mick_allen

    mick_allen Paddler & Moderator

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    the sides of your hatch doublers look to be wider than the panel sides - i suspect you plan to chamfe?. Also if you plan on adding a gasket, you may need a 2nd set of doublers to drop the flange down far enough to account for the thickness. I also don't see a flange lip.

    A secondary hatch consideration is where you have designed the hatch edges to be. If you make the edges right at the panel seams, then the resolution of the hatch tensioning system will automatically have a downward vector component from the angle of the adjacent panel - thereby helping to add tension to the hatch. If it is cutout as is, you will had to add higher bumps on top if you use an outside latch approach. ie the hatches are flat - difficult to get downward external presssure. Anyway, a consideration.

    If you don't also plot out paper forms to sprayglue onto your cnc forms, then maybe cut some slots or holes so that you can more easily align the forms on the bench with stringlines, lasers or levels - ie 2 waterline nothches and 2 centreline notches on each.

    And because of the extra ply available, i'd cut another couple forms about 12-18" from each end just to nail it there.

    anyway, some thoughts
    mick