Loose fin-box?

Discussion in 'Surfboards and Surfboard Design' started by RespectIt, Mar 22, 2019.

  1. RespectIt

    RespectIt Active Member

    27
    May 27, 2013
    So I got a single fin and am seeing suspect play in the fin-box assembly, anyway to fix this short of speaking with the builder?
     

    Attached Files:

  2. RespectIt

    RespectIt Active Member

    27
    May 27, 2013
    Note the thin space indicating play where there should otherwise be a seal.
     

  3. sisurfdogg

    sisurfdogg Well-Known Member

    Jun 17, 2013
    Get it professionally reinforced with fiberglass cloth on both sides and above and below. Otherwise you'll end up with a constantly worsening wobbly fin box rot situation. It turns ugly and your whole tail becomes waterlogged and the foam gets soft underneath the glass and then you get delamination and contamination and the board goes so slow it feels like constipation.
     
  4. RespectIt

    RespectIt Active Member

    27
    May 27, 2013
    Dang thats a pain, i was thinking a slow cure 2-1 marine epoxy may work in there nicely for sealing and structural strength once its set down in there.
     
    Notaseal likes this.
  5. Barry Cuda

    Barry Cuda Well-Known Member

    Nov 19, 2018
    If it is as new as it looks in the picture, and if the builder is nearby, have builder do it. He probably has more experience than you do having done lots of them.
    just opinion.
     
    RespectIt and DawnPatrol321 like this.
  6. jaklsurfs

    jaklsurfs Well-Known Member

    473
    Apr 26, 2015
    You say you just got it ,take it back get him to fix it ,he should do it for free
     
    sisurfdogg likes this.
  7. jaklsurfs

    jaklsurfs Well-Known Member

    473
    Apr 26, 2015
    If it was mine and the builder wont fix it, id cut the box out and reset it ,to pile cloth on top of it might not last and looks terrible,one thing tail is under water more so pressure will force water in so fix it soon cuz next it will rot your stringer
     
  8. Notaseal

    Notaseal Well-Known Member

    Apr 18, 2015
    Its probably been damaged
    untitlerope.png glass.jpg
     
  9. LBCrew

    LBCrew Well-Known Member

    Aug 12, 2009
    Looks like the box wasn't prepped properly, or the glasser who installed the box used sanding resin instead of laminating resin - the bond that's failed is between the box and the resin in the routed hole. This probably means there's not much water getting into the foam, but there's always a chance that it is... you gotta fix it, and not with marine epoxy.

    My recommendation is to pop that box out and route out the resin using the proper jig, then do a clean install. And if you can't pop the box out, rout out both the old box and the resin.

    And by the way... this is a good argument for the fin box patch to go OVER the box instead of under, and for the use of a cloth "sock" around the box. If either one of those box install methods where used here (I do both), you'd never have had this problem.
     
    Last edited: Mar 26, 2019
    capecodcdog and DawnPatrol321 like this.
  10. jaklsurfs

    jaklsurfs Well-Known Member

    473
    Apr 26, 2015
    I made these for a board im about to finish with ,glass ons are my favorite 20190108_172712.jpg
     
  11. Barry Cuda

    Barry Cuda Well-Known Member

    Nov 19, 2018
    hippie fins.....
     
  12. La_Piedra

    La_Piedra Well-Known Member

    Oct 9, 2017
    wanna see the board those are going on
     
  13. jaklsurfs

    jaklsurfs Well-Known Member

    473
    Apr 26, 2015
    Vacuum bagged over balsa with 2 oz cloth over the fabric ....very light
     
    LBCrew likes this.
  14. CJsurf

    CJsurf Well-Known Member

    Apr 28, 2014
    Looks to me like the sander might have overheated the box when he ground it down flush with the bottom of the board......I've made that mistake myself. When you're grinding boxes if you create too much heat the plastic expands and then when it contracts you lose the bond to the fiberglass.
     
    antoine likes this.