Fitting Fiberglass Fabric

Discussion in 'Fiberglass and Composite Boat Building' started by tomherrick, Feb 21, 2012.

  1. tunnels

    tunnels Previous Member

    first off you have two problems !!first theres not enough resin !! the glass is too dry !! and second the corners are too sharp !!
    glass hates going round corners !!,specially sharp corners . the diameter of an ordinary pencil is the smallest dia you should try to lay glass around !!you can always epoxy bog the sharpness back on later !!slow resin is another problem get it warm or get a faster hardener!! if it takes to long to go hard the glass will spring back and air bubbles will appear !!:idea::confused::?::p
     
  2. tomherrick
    Joined: Sep 2006
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    Location: Versailles, Kentucky

    tomherrick Junior Member

    I agree, there's not enough resin. As to the corners, C-Dory has been building boats with those lapstrake corners since 1979. I talked to their shop foreman and he told me they're currently using 2408 to construct the hull. They're using a female form, but still, they must have to do some interesting contortions to get that fabric to conform to those shapes. At U.S. Composites' suggestion, I heated the resin and hardener to around 95-110 degrees to get it thin enough to actually wet out the fabric. Otherwise their "Thin" laminating epoxy is like pancake syrup right out of the refrigerator. I didn't have to do that with West System epoxy; it was about 65 in the shop and it mixed, wetted out, and set up just fine. The stuff you see in the pics above will be removed tomorrow and reglassed with West System. Hopefully, U.S. Composite's 4:1 Fast hardener will get the job done for less than half the cost of West System epoxy; which I have about 20 years of experience using for old house work. I like that stuff...
     
  3. tunnels

    tunnels Previous Member

    The manufacture laying up in a mould will be coving the corners with a filler and possibly micro fibres in the mix first and then laying a soft glass and then putting in the 2408 so the lapstrake will have lost a lot of its shape by then !
    The soft layer will be a csm possibly or simular other wise you would be getting fibre print through to the outside .
    I used to make clinker fibreglass dinghys in my spare time at home and used polyester resin and :p2 layers of 450 csm before anything else went into the mould !!
     
  4. CatBuilder

    CatBuilder Previous Member

    Exactly. The hard edges are coved in.

    With all due respect to you Tom, you are making this project much more difficult than it needs to be.

    Cove it, or get some 6oz cloth. An entire roll of 6oz will cost you less than ordering new epoxy, that's for sure.

    You can make the cove square again by sticking some filler on there above the glass, against a couple of 1x2's that have packing tape on them and are held to each other at a 90 degree angle.

    That's how it's done when you don't have the luxury of a mold as Tunnels is describing. You'd be done already. :)
     
  5. tomherrick
    Joined: Sep 2006
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    Location: Versailles, Kentucky

    tomherrick Junior Member

    The existing hull is a quarter-inch thick. I wonder how many layers of 6oz. cloth it would take to make up that thickness? It takes six layers of 1708 to make that dimension.

    As of today, the only question that remains is whether or not the faster hardener from U.S. Composites will do the same job that West System's 205 does. If it does, it's only a little more cost for their hardener and I can sell the medium hardener.
     
  6. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    This is precisely what I described as "dams" when this thread first started (post #9).

    You can only get fabric to do so much, the rest if filler, either cosmetic or structural. It's much easier to handle, if you can mold these types of things, hence the dam suggestion earlier.
     
  7. CatBuilder

    CatBuilder Previous Member

    Wow, you just don't get how this is done, then you get testy about it. Have fun. You'd be done already if you did it the right way.
     
  8. tunnels

    tunnels Previous Member

    Simple???

    Why is glassing so complicated for some people !!
    Have resin ,add hardener ,goes hard SIMPLE !!
    Pour resin on glass soaks in and goes hard !!!
    If the product is old shouldnt be using it !!
    not going hard then needs warmth !! .
    If its to cold shouldnt be doing the job !!
    Always use fresh resin and hardener and mix properly !!
    If the corner is to sharp, sand it down a little and build it back up again later !!
    :idea::?::confused:
     
  9. tomherrick
    Joined: Sep 2006
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    Location: Versailles, Kentucky

    tomherrick Junior Member

    Testy? I don't know how you read that into it. Maybe I need to use lots of emoticons... That said, however, it is a bit frustrating to learn about fiberglass/epoxy work in a relative vacuum. In my situation, I have only books, YouTube videos, and online forums from which to learn. And those sources are full of very different and often totally conflicting recommendations; look at many of the argumentative posts on this forum about how to go about things. I have to sort through and make my decision on an approach that works best for me. Tunnels, I'm certain that glassing is simple if one learns how on the job, hands on, but I've found no such opportunity around here.

    In regard to epoxy use, I've used West System for many years with no problems; and it was simple. When I used it instead of the U.S. Composites epoxy it worked just fine and held the corners with no problem. It's this new-to-me goop that has very different and, frankly, difficult working properties that is taking some time to figure out. I'm using it to keep the costs down. We'll see how their fast hardener works.
     
  10. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    Ill agree with what the other have said, you round off any sharp edges with a router/planer/sandpaper etc.

    Then lay your glass/resin - it wont matter which type of resin you use because your not trying to fight with it.

    Then once its cured, build up the sharp edge with a solid resin and powder modified mixture. If its structural, use a silica powder, if its non structural use micro balloons as its much easier to sand it to the shape you want. You fibreglass supplier has all this stuff.

    Youll know for next time...
     
  11. tomherrick
    Joined: Sep 2006
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    Location: Versailles, Kentucky

    tomherrick Junior Member

    Well, both inside and outside corners on the lapstrake offsets and the running strakes are 1/4" radii. Perhaps that's not enough, but again, using a hotter hardener seems to work just fine.

    Thanks
     
  12. tunnels

    tunnels Previous Member

    Find a plastic sheet that is compatable with your resin cut strips 80mm wide Laminate you corner and peel ply it then role the 80mm wide plastic over the top and roll that as well . If the air cant get in then the glass will stay down on any corner ?? did this years ago on strakes on a power boat hull as they had sharp corners inside and out and always used to get long strips of air so the peel ply and plastic solved the problem !!:p
     
  13. tomherrick
    Joined: Sep 2006
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    Location: Versailles, Kentucky

    tomherrick Junior Member

    Tunnels,

    The individual words you write are regular, normal, comprehensible words. I'm certain you know what you're talking about, but what comes across here is incomprehensible to me. Knowledge, skills and ability are one thing - conveying them to someone else is a whole 'nuther thing...

    Thanks, though...
     
  14. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    nice trick tunnels, ill have to try that one day...
     

  15. tunnels

    tunnels Previous Member

    I have worked with asians for to long !!, most of them dont have any understanding of english at all specially the older ones so have to show and do !!
    My translator lady has left the company but life goes on !! Like working with handicapped adults !!
    Children are easy and learn so fast !!.
    What part dont you get plastic sheet ?? peel ply ?? wet glass?? :p:eek::D:p:?:
     
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