Cloth Lap

Discussion in 'Fiberglass and Composite Boat Building' started by alyeska, Aug 18, 2010.

  1. alyeska
    Joined: Oct 2009
    Posts: 12
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    Location: Australia

    alyeska Junior Member

    Hi Guys,
    Just want to know what the minimum overlap on cloth joins I can get away with. Layup is 1 x 450grm 0/90 double bias ( outside skin ) over 10mm corecell. Whats the best method of laping cloth so as to keep the joint "bump" small for ease of fairing?
     
  2. apex1

    apex1 Guest

    Well,
    the minimum is zero, and that would solve the prob with fairing.

    But that was not what you wanted to hear.

    A bit more info about the structure you are building may help to get a answer you expect.

    Regards
    Richard
     
  3. tinhorn
    Joined: Jan 2008
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    Location: Massachusetts South Shore.

    tinhorn Senior Member

    Zero overlap would be a butt joint. Bad idea. Since it's going over Corecell, I'd just sand a shallow groove in the foam wide enough for the overlap. Since I'm not an engineer, I'll leave it to others to recommend the amount of overlap.
     
    1 person likes this.
  4. tunnels

    tunnels Previous Member

    Put a slight recess in the foam where the join will be so the join can be filled over rather than sanding it off . :confused:
     
  5. alyeska
    Joined: Oct 2009
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    Location: Australia

    alyeska Junior Member

    Thanks for the replies, will go with the rebate in the foam, I'm guessing 30mm overlap should be enough.
     
  6. tunnels

    tunnels Previous Member

    Make the recess 35 mm wide and the depth of one layer of glass!! Wipe a layer of filler over the whole join before you sand the hardened resin and glass and press it into the join , let it set and then sand filler and glass level just a fraction below so when you wipe the top layer its sanded and gives a perfect finish . :p
     
  7. apex1

    apex1 Guest

    Where is that guess based on?

    You have a uncommon single layer setup here, and only 0,5 -0,6 mm laminate thickness. I would not (and did not) give any recommendation without knowing the whole story.

    All nice thoughts tinhorn and tunnels, but to advise in a serious manner we have to know more about the application.

    Regards
    Richard
     
  8. alyeska
    Joined: Oct 2009
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    Location: Australia

    alyeska Junior Member

    Laminate is a single layer outer skin over 10mm corecell on a 6m hull, using ampreg 22 resin
     
  9. apex1

    apex1 Guest

    Well one can hardly call that much more info.

    So be it........
     
  10. alyeska
    Joined: Oct 2009
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    Location: Australia

    alyeska Junior Member

    If you tell me what extra info you need........
     
  11. apex1

    apex1 Guest

    That sounds very thin and flimsy. Is it for a canoe or the ama of a multihull?

    I just wanted to grasp how much safety factor is required in your layup.

    As far as I understand it, that will be the entire structure of the boats hull?

    1mm glass 10mm foam?

    We use already 10cm overlap on our wood epoxy hulls which are just sheathed for abrasion resistance! They are 2x 300gsm making roughly 1mm.

    Regards
    Richard
     
  12. alyeska
    Joined: Oct 2009
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    Location: Australia

    alyeska Junior Member

    Layup is inside 1x 300gsm - 12mm corecell (not 10mm my mistake ) - 450 gsm 0/90 biaxial outside. Boat is a 7.5m sportsboat with lots of internal structure including carbon reinforcement around keel/ shroud structure
     
  13. AndrewK
    Joined: Mar 2007
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    Location: Australia

    AndrewK Senior Member

    If this is a sports boat and your are using carbon and glass then I am guessing that your are vacuum bagging as well. If this is the case your laminate thickness will be <0.5mm so not worth the effort to rebate.
     
  14. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    For all those who don't have any idea what a "sportsboat" is, I'm thinking this must be it.....

    http://en.wikipedia.org/wiki/Sportsboat

    The hull is 6m long. Or 7.5m long.

    ;)
     

  15. tunnels

    tunnels Previous Member

    Ok another word for a trailer sailer !!
    Had one long time ago but got sick of living my life on a 45 degree angle just about every where i wanted to go, And getting from point A to B via every other letter in the alphabet used to piss me off !!
    I like to look at where i want to go , turn the key and get there asap !!
    I like yachts , i love building yachts and have made 100s of all differant sizes over my life time but i like powers boats better ,But that just me !! :p :D :)
     
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