Epoxy/glass schedule question

Discussion in 'Wooden Boat Building and Restoration' started by bobbrown, Jan 23, 2022.

  1. bobbrown
    Joined: Jul 2021
    Posts: 29
    Likes: 2, Points: 3
    Location: SE Georgia

    bobbrown Junior Member

    2 layers tape on seams. Will be unable to put fiberglass on hull within reasonable time.
    So, the question centers on preparing the epoxied seam tape for the hull epoxy. The seam tape has no fill coat some weave is still present. Confused if I need to do any sanding before the hull glass since sanding would sand the top tape weave which I think is not advisable.
    Will the exposed tape weave be enough tooth for the hull glass.
    Thanks
     
  2. Blueknarr
    Joined: Aug 2017
    Posts: 1,327
    Likes: 328, Points: 83
    Location: Colorado

    Blueknarr Senior Member

    Welcome to the forum.

    What are you working on?

    All depends on cure time vs delay time.

    A few days delay will still develop primary bond.




    Odd much of my original response disappeared.

    Now you get the short answer

    -Peal-ply-
     
    fallguy likes this.
  3. fallguy
    Joined: Dec 2016
    Posts: 6,068
    Likes: 1,213, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Sanding with 40/60/80 grit is advisable if there is even an overnite delay. The grit depends on the tapes. Yes, primary bond can still be achieved on some resins for 72 hours no sanding, but I have sanded these bonds and didn't always like the layers sheeting off; so I started sanding all overnite cures long ago.

    6 oz tapes 80 grit and just knock of sheen and avoid sanding thru

    biaxial tapes no mat 60 grit, mat tapes 40 grit

    I found that the tapes were just awfully rough to glass over once cured. A good bubble buster roller can manage roughness, but humps are really not easy to fair out..

    Also, for thick tapes like 1208 or 1708; I precoat the steps they create before glassing over the top with thickened resin. More important on boat bottom where you want zero voids than say inside tapes..

    Blueknarr mentions peelply. It is also a good solution and will help keep glass smoother for follow on layers and it will stop drips and runs from happening on mat backed tapes. I always regretted not using peelply on the inside of my boat because one seam was 3 tape layers and it ran pretty good. I applied 200 feet of tapes that day and didn't bother woth peelply and wish I had

    Drips and runs should also be sanded out if they occur which is not good on real thin ply cores. Depends a bit on what you are building.
     
  4. bobbrown
    Joined: Jul 2021
    Posts: 29
    Likes: 2, Points: 3
    Location: SE Georgia

    bobbrown Junior Member

    Thanks guys….14 foot flat bottom skiff for grass and mud flats in southern GA…go DAWGS!
     
  5. fallguy
    Joined: Dec 2016
    Posts: 6,068
    Likes: 1,213, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Probably 6mm ply and 12 oz biax tapes. Those, I'd either peelply or sand with 60 grit. They have stitching that is higher than needed for follow on layers. The stitching is a good sanding gauge; don't go past removing the stitches.
     
  6. bobbrown
    Joined: Jul 2021
    Posts: 29
    Likes: 2, Points: 3
    Location: SE Georgia

    bobbrown Junior Member

    Fallguy had a point that I was considering. Fairing in the tape seams before applying the hull glass. Wouldn’t take long and might save some work later on
     
  7. fallguy
    Joined: Dec 2016
    Posts: 6,068
    Likes: 1,213, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    I don't know how you plan to do the hull glass. I prefer to roll all but light wovens off a roll with lotsa sharpie marks to make sure length and overlaps land correctly. This allows you to prefair hot with thickened resin. Typically fumed silica because it knifes so well. A 4-6" flat trowel works nice; avoid excess; you can always be a little light, but the preloading is really wise on the bottom for perfect bonds.
     
  8. bobbrown
    Joined: Jul 2021
    Posts: 29
    Likes: 2, Points: 3
    Location: SE Georgia

    bobbrown Junior Member

    Due to timing my basic plan is…2 offset seam tape…fair tape edges…then hull glass and faired…then paint. Any need for low density filler to fill tape weave. Thanks a lot for the advice
     
  9. messabout
    Joined: Jan 2006
    Posts: 3,227
    Likes: 374, Points: 83, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    Attention Bobbrown; The Dawgs already went. Rather convincingly I might add. ................Now back to boats..........
     
  10. fallguy
    Joined: Dec 2016
    Posts: 6,068
    Likes: 1,213, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Fairing is quite a task. For biax glass; sand all the stitching a bit and remove most of the sheen. You won't get it all. For a boat such as this, a gallon and a half kit of commercial fairing compound is the way I'd go.
     
  11. Blueknarr
    Joined: Aug 2017
    Posts: 1,327
    Likes: 328, Points: 83
    Location: Colorado

    Blueknarr Senior Member

    Peel-ply would eliminate the pre fairing
     

  12. bobbrown
    Joined: Jul 2021
    Posts: 29
    Likes: 2, Points: 3
    Location: SE Georgia

    bobbrown Junior Member

    Thanks guys…very helpful
     
Loading...
Similar Threads
  1. Elias_Fleishman
    Replies:
    15
    Views:
    19,507
  2. smokinone8
    Replies:
    18
    Views:
    7,781
  3. Raptor88
    Replies:
    48
    Views:
    1,527
  4. AwJees
    Replies:
    1
    Views:
    491
  5. tonyg99
    Replies:
    6
    Views:
    2,599
  6. flyingvranch
    Replies:
    10
    Views:
    4,727
  7. RMMager
    Replies:
    14
    Views:
    3,893
  8. aaronhl
    Replies:
    11
    Views:
    3,865
  9. Skookum
    Replies:
    14
    Views:
    3,281
  10. abosely
    Replies:
    44
    Views:
    8,383
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.