Replacing My Stringers

Discussion in 'Fiberglass and Composite Boat Building' started by mikefromtoledo, Apr 9, 2010.

  1. mikefromtoledo
    Joined: Apr 2010
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    Location: toledo,ohio

    mikefromtoledo Junior Member

    Hi, I am a what you call a newbee at boats but im jumping in and baffled. I am replacing the stringers in my 19ft 4in 1979 Thompson Fisherman i didnt expect to find what i did i though it was rott and it was termites eww boy anyway so i desides to pull all the stringers and redew the because they got in everywhere along with black and things fricken hurt when they bite and there was alot!!! my qeustion is when i replace the wood and strart the fiberlass how should i go about it? what materials should i use like what ounce of cloth should i use and other tips about doing the fiberglass for the stringers any and all criticism and ideals are welcome. also i'm replace the side gas tanks and putting it in the floor. what do you think the reason i need a new tank is because i geuss someone else needed them more then me along with everything else they could take off thanks for the look looking forward to hear from ya :confused:
     
    Last edited: Apr 9, 2010
  2. alan white
    Joined: Mar 2007
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    Location: maine

    alan white Senior Member

    It wasn't termites. They just saw a good deal and went for it. The stringers were wet and probably rotting already.
    Use the search function to find endless threads on stringer replacement. Good luck.
     
  3. mikefromtoledo
    Joined: Apr 2010
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    Location: toledo,ohio

    mikefromtoledo Junior Member

    stringers

    ya they got a good deal till i poured acid onem;) payback
     
  4. tedl2007
    Joined: Apr 2010
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    Location: Vancouver, WA

    tedl2007 New Member

    Replacing stringers

    I am doing my home work to repace stringers. To date have found to use spruce or marine plywood for stringers.

    Still do not understand what to put between new stringers and hull for any voids/gaps and eliminate hard spots. Discussions to date are using resin with fiber filler, 3M 5300 or foam.

    Any feed back will be greatly appreciated.

    Ted
     
  5. erikgreen
    Joined: Mar 2008
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    Location: MN, USA

    erikgreen Junior Member

    Bedding

    You can use anything at all, or nothing.

    Stringer bedding in a fiberglass boat is there to ensure that no hard spots, which are hull areas that don't flex with the rest of the hull, are created.

    To do this you need to keep the structural members like stringers away from the hull glass unless the stringer *perfectly* matches the hull contour, IE it has less than a 1/16" or so gap between it and the hull along its entire length.. usually this is impossible, so you fill the gap to ensure even contact or you space the stringer off the hull with another material, or both.

    You want the load from the stringer to be transferred to the hull by the fiberglass holding them together, not by the hull pressing against the stringer.

    Most home boat rebuilders use putty... resin (poly or epoxy) with a powder filler, like milled fibers, wood flour, or something else. This does three useful things - it ensures no hard spots by making contact even, it permits formation of fillets at the joint which ease the fiberglass transition from hull to stringer, and it adds strength by increasing the contact surface that holds the stringer to the hull.

    Some other folks use PVC foam strips or even pink insulation foam. Cut a strip so it's as thick at the top as the stringer, and a bit wider at the bottom, and about a half inch high. If you cut it right you can put it down with the stringer on top of it, then glass both in place.

    Lately a fad has been to use PL premium polyurethane construction adhesive. It's relatively cheap, comes in ready to use form, and glues the stringer in place. But it doesn't add strength due to its flexibility being much greater than the surrounding glass, and you can't really make fillets out of it.

    You can even use air, just make a gap between hull and stringer, although this is difficult to do well for a number of reasons.

    You can find a lot of people discussing these sorts of repairs at forums.iboats.com... there's a lot of people who frequent both forums.

    Erik
     
  6. mikefromtoledo
    Joined: Apr 2010
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    mikefromtoledo Junior Member

    This is what i found when i took mine out. I found the foam that goes in the rest of the bout under the stringer. It looks like they sprayed it on and then shaped it so the stringer would fit right on top of the foam at about 1/4 or 1/2'' thick of foam. Your probly thinking well it could of just sliped under the stringer when the foam was put in the rest of the boat but keep in mine that the stringers where incapsulated in fiberglass so there no way that the foam could of slip through or expanded through. So ya that's the way they did it, it don't seem like a bad ideal either. I geuss it would have a cushion but be strong enough so the fiberglass wouldn't give to much but just enough. well thats my thought of the day whats yours
     
  7. mikefromtoledo
    Joined: Apr 2010
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    Location: toledo,ohio

    mikefromtoledo Junior Member

    well still working on grinding everything down and prepin the boat for its new bones, right now i'm about to get the marine plywood for the transom. just keepin ya'll updated thanks for all the sopport one day at a time
     

  8. tedl2007
    Joined: Apr 2010
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    Location: Vancouver, WA

    tedl2007 New Member

    Thank you mikefromtoledo. That does sound like a very easy way to do it.
    shim it into the right height, foam the gap, let it sit, and then pull shims and foam those holes.


    erickgreen, from your explanation I understand about hard spots. A hard part is basically a portion there is no resin or foam whick allows the stringer and hull to bang against each other.

    I did read an article on using 3M 5200. either one of you have any thoughts on this material? Looks like the material would be also

    Thanks again for the replys.

    Ted
     
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