Tips on fiberglassing plywood hull

Discussion in 'Wooden Boat Building and Restoration' started by hospadar, Jul 19, 2011.

  1. hospadar
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    hospadar Junior Member

    I'm working on my first boat right now (whoooooooo!) and I've just finished gluing all the seams and am getting ready to glass the entire hull.

    It's a little 12 foot skiff - the summer breeze: http://www.simplicityboats.com/summerbreezeduckworks.html

    I was wondering if anyone had any tips on glassing the hull, or could point me toward any resources that cover the process in detail. I basically know what to do, but I'm worried about getting the glass to lay flat on all the curves and corners - especially around the stem and where the stem meets the bottom. Also I'm concerned there may be other details I'm currently unaware of that I'll miss.

    Thanks!
    Luke
     
  2. PAR
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    PAR Yacht Designer/Builder

    Bateau.com has some videos as do several other locations including westsystem.com and systemthree.com. Make sure all the corners are well radiused and preform a dry run with your fabric, so it can be cut to size, darted where necessary and possably marked to "key" it to the surface. Some places there will be overlaps, which is normal. You can cut and butt or better yet is to plan for the over lap as it offers slightly more material for abrasion in exposed areas.
     
  3. BATAAN
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    BATAAN Senior Member

    Carefully pick your fabric and follow your boat designer's recommendations. Glass goes on much easier when it's light and flexible. Pre-fit the pieces and roll each around a broomstick or something smooth and similar to make it easy to lay on the hull when installing. Consider a polypropylene fabric due to its 'sleazy' nature which just means it accommodates compound curved surfaces well. WEST resins work nicely. Do not use polyester resin for sheathing. Polyester will not stick to epoxy if you have built your boat that way, also it shrinks a good bit in curing, does not adhere very well to wood and is generally inferior for sheathing.
    This dinghy had its bottom sheathed 15 years ago and hasn't been repaired since after many hundreds of rocky beaches.
    The white/yellowed paint on the bottom is 'Interprotect 3000' from Interlux that is part of their blister repair system, an incredibly hard and chafe (you cannot sand it) resistant coating I used instead of antifouling as this boat lives out of the water usually.
     

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  4. lewisboats
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    lewisboats Obsessed Member

    Along with the above...drape your cloth and let it sit for two or three days to get used to the shape...it will lay flatter and tighter to your ply if it has had a chance to get the creases and wrinkles to ease out a bit. Use a squeegee to pull your resin around, it will result in a tighter cling to the ply and less floating in the resin. Recoat while the resin is still slightly tacky...that way you get a double bond...mechanical and chemical. Use a lightweight filler...microballoons are good...to fill the weave and as a fairing compound to get a smooth finish.
     
  5. thedutchtouch
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    thedutchtouch Junior Member

    note: this wasn't on a boat, but should still work the same.

    after laying out the fabric and cutting to shape as described above, coat the surface with a light coat of resin, and let it dry slightly, this tacky layer will help hold large sheets of cloth in place when rolling it out, and when squeegeing, particularly on vertical surfaces.
     
  6. hospadar
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    hospadar Junior Member

    Thanks!
    That's just what I was looking for.
     
  7. BATAAN
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    BATAAN Senior Member

    Show us pictures when you are done?
     
  8. hospadar
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    hospadar Junior Member

    of course!
     
  9. Northman
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    Northman Junior Member

  10. hospadar
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    hospadar Junior Member

    So,
    I just did the fiberglassing last night and on the whole it came out pretty well. I painted a thin coat of epoxy on, waited until it was tacky, then spread and wetted out the glass. putting the tacky coat on first was nice, it held the cloth in place while I worked, and I think it prevented more problems than it caused, but there were some spots where I didn't lay out the cloth correctly and then later couldn't work out some bad spots.

    My question now is - what is the best way to repair blisters/bubbles in the fiberglass? There are a couple places - some near edges, some near corners, some in the middle of a flat area where the fabric didn't quite lay flat and I had a little blister.

    I imagine I could:
    a) sand down the blister, put a patch over that location
    b) attempt to fill the blister with epoxy (I realize this would give me some floated fiberglass, and my hull wouldn't be perfectly faired, but it's a small little funboat so those things don't bother me)

    I'm leaning towards option 'a' - I've attempted option B before (when I was taping the seams) and although it sort of worked, it took a couple rounds of gluing and some bubble were hard to fill completely. in some of the smaller bubbles, I may just sand off the bubble and lay down some extra epoxy for filler and not bother with a patch. The fiberglass isn't really necessary for this boat, I just wanted to attempt it to get some extra durability and overall toughness (and to learn to glass of course)

    Thanks again for all the help I'm getting.
     
  11. lewisboats
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    lewisboats Obsessed Member

    Option A without the patch
     
  12. PAR
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    PAR Yacht Designer/Builder

    When it's fully cured, hit it with a disk grinder and knock the blisters or other bad spots down to the surrounding area's level. You can apply a patch if desired, though just filling the area with thickened epoxy will do just as well.
     
  13. hospadar
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    hospadar Junior Member

    I've got another problem:
    ALL I CAN THINK ABOUT IS BOATS ALL DAY LONG.

    I suppose that happens when you make a boat
     
  14. lewisboats
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    lewisboats Obsessed Member

    YYuup!
     

  15. Landlubber
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    Landlubber Senior Member

    "ALL I CAN THINK ABOUT IS BOATS ALL DAY LONG."....well hopefully that will help solve problems before they occur...the blisters are simply ground flat and smooth, filled with cloth and ground smooth again...no big deal, and don't fret over them. Next time you will have understood how to avoid them, and by thinking about the boat all day, well that is a good thing.
     
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