cloth print and ripple

Discussion in 'Fiberglass and Composite Boat Building' started by hyboats, Oct 20, 2011.

  1. hyboats
    Joined: Jun 2010
    Posts: 78
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Sydney

    hyboats Junior Member

    when we take the deck out from mold the surface is very very smooth and shinning, no cloth print, no ripple. But about ten days later cloth print and ripple occurred, especially when deck is under sunshine. I think it is after cure but we don't how to slove this problem
    the first layer is 50g/㎡ surface mat then two layers 350g/㎡ mat
    --------Who can help me
    thank you !
    __________________
     
  2. rwatson
    Joined: Aug 2007
    Posts: 5,866
    Likes: 299, Points: 83, Legacy Rep: 1749
    Location: Tasmania,Australia

    rwatson Senior Member

    Dark colours accentuate the problem.

    What 'goo' are you using ?
     
  3. tunnels

    tunnels Previous Member

    What is the patern you are getting?? csm or cloth print through ??
    The ripples could be pre-release from the mould as it cures !! this could be dirrectly related the a surplus of resin left in the glass to cure . Pools and duddles etc etc
    Glass floats if you have to much resin !!!
    What you are exsperiancing sounds like resin shrinkage!, as it cures it draws and shrinks , some resins are worse than others also the type of catalyst you use can make the resin heat more , you need quick gel slow cure Catalyst ! .
    Your surface matt is what exactly ??
    is it Tissue ??
    350 grams X 2 Is way to much glass for a first layer and its loaded with resin so this is where your shrinkage is coming from initally . if you want csm then use a 450 gram P matt ! must be P" matt !!
    Do you understand the differance between P matt and E matt ?? !
    All we use just a skinning tissue with 300 gram csm p mat and use Vinylester resin . By nature Vinylester has less shrinkage and goes harder than the polyester . NEEDS TO CURE ABOUT A GOOD 12 HOURS IF POSSIBLE then carry on making the boat !
    What is the lay up schedual for the boat ?
    Do you use woven glass OR stitched glass ??
    As already mentioned colors have a lot to do with Shrinkage and draw from the sun !!
    as well dark colors draw so much heat !!
    light colors not so much !!
    white is best but hard on the eyes or very light gray that in the bright sun looks white but is easyer on the eyes .
    Another product you could look at is barrier coat !!.
    Never used it myself so dont have any first hand exsperiance to pass on about it .
    If it was me i would do tissue , 450csm with, vinylester resin ,check what catalyst to use with it !,let it gel and cure for 12 hours ,or more then build the boat . and see what you get !!. :)
     
  4. tunnels

    tunnels Previous Member

    Any chance of getting some pictures ?? Keep us informed how you get on !!and what you tried and what worked !!

    I have been through all these issues a few times and its a process of elimination till you find what works for what you are doing and the materials you are using and how you are using them . as I said even a simple thing like changing catalyst can help solve the mystery !
    I wrote a few pages for our managment in this company discribing the many causes and possible remedies !!:D :p
     

  5. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 89, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    Indeed there is a tad too little info to give directions in which to move.

    What materials do you use exactly, including gelcoat, peroxides, fabrics, and which time schedule is kept, including temperatures.

    Do you happen to have a barcol meter?
     
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