fiberglass correct lamination process, opinion

Discussion in 'Materials' started by linda.vrdoljak, Feb 8, 2015.

  1. linda.vrdoljak
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    linda.vrdoljak Junior Member

    hi there, as some of you know we (wife and myself) are building mold for 17m motor yacht,
    http://www.boatdesign.net/forums/cl...r-yacht-iso-sct-hullscant-will-pay-52462.html


    I'm trying to review/undersand "proper" laminate, since its strength is thickness related in terms of scantling... (to correct myself, material type)

    here is excel spreadsheet I made of Safeheaven laminate Pilot boat, and SeaFish, (working boat in UK), and I consider it solid/good lamination, its working boat.

    See excel table, and let me know if I understand things correct,

    Also your example of proper lamination is welcome,

    thanks,
    Linda
     
  2. linda.vrdoljak
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    linda.vrdoljak Junior Member

    re

    spreadsheet
     

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  3. gonzo
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    gonzo Senior Member

    Hi Linda:
    You really need to talk to the designer. A hull laminate is only part of the whole structure. It will be determined by structural reinforcements, laminating process, operating conditions, target speed and others. In other words, if all the preliminary design work is done, the hull laminate is generated by it. What does the Naval Architect or Engineer say about it?
     
  4. TANSL
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    TANSL Senior Member

    Forget the idea that the resistance is related to the thickness because it is not correct. Resistance depends on the mechanical properties of the material, in turn, depends on the glass content of each layer.
    The scantlings of composite materials is not easy and there are many factors that must be considered. It is, at last, after all, a heterogeneous material and is thus necessary to study how it behaves each of the layers.
    The sheets 2, 3 and 4 of your spreadsheet are correct. I really like the drawing of the "SeaFish" sheet, is the technique I use is my projects.
     
  5. gonzo
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    gonzo Senior Member

    The diagram of the laminate tabbing shows the smaller laminate first and larger outside. The diagram clearly shows the bending of the fabric, which is a bad structural design. To keep proper fiber alignment, the largest or widest strip goes first, getting smaller afterwards. That system was used in the past, but all recent testing indicates that it is not the best.
     
  6. TANSL
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    TANSL Senior Member

    Gonzo, as I see you have not understood anything, I will try to explain. I say that I like the technique and that technique is the one I use. I've never talked about the composition should go in each layer because, if you knew how to calculate scantlings, you would know that it depends on many factors (aside from the very obvious you commented on the post # 3) that currently do not know and therefore I would be an ignorant if I said what material should be placed in each layer.
    I am happy to teach you. You're welcome.
    You think, really, it all means something?
     
  7. linda.vrdoljak
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    linda.vrdoljak Junior Member

    thanks for input,

    My idea was, to ask, is this correct layup schedule for nice finish?

    pink is not to be changed, and blue layer I can "play with" to satisfty thicknes and strength requirement to ISO scantling soft, SSC, or what have you...
     

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  8. TANSL
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    TANSL Senior Member

    To determine the composition of the layers, it is necessary to know the concepts I've highlighted in red.
    Without knowing these three items, anything that is said is reliable.
     

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  9. linda.vrdoljak
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    linda.vrdoljak Junior Member

    Gonzo, I found architech, they do designs of smaller sailing yachts, and his particular yacht was chosen for yacht of the year somewhere in Europe, they never did 56' but they understand basics.

    He told me why is thin, 11mm because they like to work with quadriaxial any time they can. We both didn't have much time to discuss it further at that moment, but we are going to.

    15.6m hul length, 20t yacht (35, 50knots) under B category, under ISO.
    I got 13.3mm with csm, 11.7mm with over-stuffed roving with no smooth layers.
    Ignacio got 12.5mm with his schedule of material, correct one, thin layers on faceplate not to ugly the glasslike gelcoat.

    Only thing I mind is price of quadriaxial, is more than material I can get on wholesale like comman csm and roving, just like the one used in Safeheaven pilot, and SeaFish.
    Not state of the art examples, but still good and with good reputation, even with "outdated" technique of laminating Safeheaven got working boat of the year, so why go crazy with James Bond stories.

    This is fist out first boat, I have to finish papers, pay warehouse, and I can't afford any
    extra complications, expences. this is 2 people project, for now.
    I have to talk to architect to go easy with "not easy to get, or expencive stuff"
    I must see what material is in stock.

    So I safeheaven "model" with some less craziness on CSM they did 900g in 2nd and 3rd code. I found people do 600g in 2nd and 3rd layer, Ignacio gradualy 300, 450, 600.

    My calc for model I made out of foam to get area, was 2.88ton with no stiffeners, for minimum thicknes to pass ISO12215 with csm300500rw, and if I use architect material price goes up some 40-50%, not fun.

    I'll get his schedule of material what in the hack did he use to be 11mm thin, and to cost me more.
     
  10. gonzo
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    gonzo Senior Member

    Is the Architect recommending tabbing from small to large? That system produces sharp corners on the fibers and is not recommended. Seems like you either don't trust the Architect or are trying to modify his design. I don't really understand the reference to James Bond stories.
     
  11. TANSL
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    TANSL Senior Member

    Sorry for being totally disagree with these statements.
    - Produces sharp corners: Yes, What ?. For example, in reinforcements this is good.
    - It is not recommended: Who says it is wrong and why ?. All we learn a lot if you explain.
    The outer and inner layers are supporting a higher stress. Accordingly we all would try to put tough tissue in them, but the warp of the fabric would be visible from the outside. Therefore all attempt to make a first light coats. There shipyards only put 2 layers of mat and other shipyards prefer to place 3. But all start with gel coat, mat, roving. I never thought it would be necessary to explain this.
     
  12. gonzo
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    gonzo Senior Member

    It is Engineering 101: avoid sharp corners at all costs. Read any engineer primer; all the basic information there.
     
  13. TANSL
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    TANSL Senior Member

    That is absolutely true, but you should read a little more, and think more, to understand why that does not apply in the case at hand. Sorry, Gonzo, you're wrong again. In addition to reading, it is necessary to think. But again, what I have highlighted in your statement is completely true, I have no objection to admit.
     
  14. linda.vrdoljak
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    linda.vrdoljak Junior Member

    Re

    So what is the deal with corneres, if stress is to concentrated and high add extra seam to hold it, gelcoat will not crack if is thin enough, all plastic boat are alike.

    Gonzo what is better laminate schedule over
    "Standard" one ? This Safeheaven for example. I cant have texture print at faceplate.
     

  15. gonzo
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    gonzo Senior Member

    Corners should be rounded or radiused to avoid high stress areas.
     
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