1968 Saftmate - Stringer Work and Question

Discussion in 'Fiberglass and Composite Boat Building' started by atengnr, Sep 25, 2019.

  1. fallguy
    Joined: Dec 2016
    Posts: 2,002
    Likes: 116, Points: 63, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Smell is pretty bad for working in your garage is all.
     
  2. atengnr
    Joined: Jun 2006
    Posts: 20
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: MI

    atengnr Junior Member

    Yes i used poly in 97 on this boat
     
  3. atengnr
    Joined: Jun 2006
    Posts: 20
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: MI

    atengnr Junior Member

    So did a little grinding to remind myself of the mess this makes. Can I get away with just roughing up the woven tapping or do I need to grind off?
     

    Attached Files:

  4. ondarvr
    Joined: Dec 2005
    Posts: 1,990
    Likes: 147, Points: 63, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    You don’t need to grind it off if it’s in good shape and securely bonded in place. Many times the stringers are glassed in so poorly that it all needs to be removed though.

    For a good bond you need to thoroughly grind the surface, 100% of it.
     
    fallguy likes this.
  5. fallguy
    Joined: Dec 2016
    Posts: 2,002
    Likes: 116, Points: 63, Legacy Rep: 10
    Location: usa

    fallguy Senior Member


    ^
    +

    I would make sure also to use thixo on all of it to avoid lotsa air on the new stuff. I am repeating myself, but it is best.
     
  6. ondarvr
    Joined: Dec 2005
    Posts: 1,990
    Likes: 147, Points: 63, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Using thixo putty will reduce the strength of the bond, only on rare occasions should any type of putty be applied first if strength is a concern.
     
  7. atengnr
    Joined: Jun 2006
    Posts: 20
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: MI

    atengnr Junior Member

    Thanks all. Can i leave the lip of existing floor and epoxy putty the new floor to this with 1708 tabbing extending over this joint? The wood is in good shape (rot was not reason for opening up floor).
     
  8. ondarvr
    Joined: Dec 2005
    Posts: 1,990
    Likes: 147, Points: 63, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Which type of resin do you plan to use for the rest of it? Either type will work.

    It’s best to stick with one resin type when doing a rebuild.

    Yes you can bed the floor in putty, or any good adhesive, then tab it in place.
     
  9. atengnr
    Joined: Jun 2006
    Posts: 20
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: MI

    atengnr Junior Member

    Was planning to use epoxy resin just because i like the idea of overkill. Could i use some construction adhesive to bond the new floor to old or make putty from epoxy?
     
  10. fallguy
    Joined: Dec 2016
    Posts: 2,002
    Likes: 116, Points: 63, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Putty vs air?
     
  11. ondarvr
    Joined: Dec 2005
    Posts: 1,990
    Likes: 147, Points: 63, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    There shouldn’t be any air, all surfaces need to be sanded smooth, there shouldn’t be any depressions large enough to not be able to glass into.

    Putty is resin with fillers, it’s weaker than than the glass layup, using it as the first layer limits your bond strength to that of the resin itself. You can add glass fibers, but short ones don’t add much strength, and longer ones are harder to work with. Plus the resin to fiber ratio is still high, you want less resin for strength.

    If someone is looking for the best properties possible you don’t use it.

    In a radius it helps to keep a uniform radius with less air, but the putty can be the weak link there too.
     
  12. ondarvr
    Joined: Dec 2005
    Posts: 1,990
    Likes: 147, Points: 63, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    I should clarify it a little.
    The bond is the same, it’s the resin rich layer of putty that can fail.
     

  13. atengnr
    Joined: Jun 2006
    Posts: 20
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: MI

    atengnr Junior Member

Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.