Combining E-Glass and Carbon (or any cloth with different stiffnesses)

Discussion in 'Materials' started by bryson, Dec 14, 2020.

  1. KD8NPB
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    KD8NPB Senior Member

  2. bryson
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    bryson Junior Member

    @KD8NPB there is no floor -- the "floor" of the cockpit is just the inside of the hull. If I ever do a floor though, I will be using some of that foam mostly to fill sealed cavities. Thank you for the link.
     
  3. fallguy
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    fallguy Senior Member

    It does not matter how many times the internet repeats the error. A boat has a sole which is walked on and a floor in a boat is a frame.

    573F1328-3979-4029-BEF4-4185AD1B0E84.png
     
  4. Eric ruttan
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    Eric ruttan Senior Member

    If I have a simple foam and glass boat, infused, and i walk on the lowest interior part of it, what is it properly called?
    Is it the 'sole', because I am walking on it, or the 'floor' as it is the boats frame?
    Or is there no proper frame in this case... So the boat has no floor?
    Or does the boat have no sole, as you walk on the frame?

    P.S. thank you for the vocabulary lesson.
     
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  5. Rumars
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    Rumars Senior Member

    It's properly called the hull bottom skin. A floor is a transverse structural member, and it is separate from the frame. Frames with integral floors are called ringframes. There are boats without frames that still have floors, and boats without both.
    A sole is a plate, removable or not, structural or not, that separates the cabin from the bilge. Everything under the sole is the bilge. The sole can rest on the floors upper face, or not. If you don't have a sole you don't have a bilge.
    If the boat has an inner cosmetic skin covering the hull skin, that is called the ceiling, and not all boats have one. It covers the hull sides, from the sole to the hull-deck joint. Many modern boats have a molded ceiling that incorporates the sole, furniture and partitions, that is called a liner.
    The part that covers the inside face of the deck is called the overhead.

    From the outside in we can have: hull and deck skin, longitudinal framing (keel, stem, sternpost, stringers, etc.), transverse framing (floors, frames, bulkheads, etc.), sole, ceiling, overhead. The only mandatory component is the hull skin, everything else is optional.
     
  6. bryson
    Joined: Dec 2018
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    bryson Junior Member

    An update for anyone interested -- I received another sheet of 3/4" H60, and also some cloth samples. The 18 oz (610g/m2) cloth and WR seem similar in thickness, but the WR is significantly stiffer and more coarse. In fact, it is so much stiffer that it almost seems like there's a binder in the roving, though I don't actually think that's the case. I think I've decided to use the 18 oz cloth, since it's very similar to what I'm familiar with, and should still build thickness quickly.

    The new schedule will be:

    outside: 3x 10 oz (30 oz existing skin) + 2x 18 oz cloth. Should result in a skin thickness around 2.75mm (total 2240 g/m2 cloth). I may add another layer of cloth, but not sure if it's necessary. I will also probably orient the cloth so that it doubles along the length of the keel, with around an 8" overlap.

    inside: I might sand the current skin a little thinner, since this should be the new neutral axis and will require less strength. I will add a layer of 3/4" core, and glass the new inside skin with 3 layers of 18 oz cloth. This should result in a skin thickness around 2.3mm or so (total 1830 g/m2 cloth).

    @rxcomposites -- what do you think of this layup? Final result should be a core thickness around 39mm, with approx 2.3mm top skin and 2.8mm bottom skin (total panel thickness ~44mm). Is there anything you would add or change? I'm hesitant to incorporate CSM with the epoxy since I worry about the extra weight for minimal benefit, especially since I'll be adding significant weight already by doubling the skin thickness. Putty made from Q-cells and/or silica should prevent the weave from printing through.
     
  7. fallguy
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    fallguy Senior Member

    I realize I am not rx, but don't you want the wr on the inside for the stiffness?

    I understand the hesitation on the outside.
     
  8. bryson
    Joined: Dec 2018
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    bryson Junior Member

    I don't think that the WR will end up any stiffer than the cloth, provided the thickness of the skin ends up the same. I believe the fibers used are still the same type of e-glass and will behave similarly, although the WR will result in a more resin-rich layup, which I'm sure will have a slight effect. Maybe a slight change in stiffness, and I'd expect a reduction of strength with less glass fiber in the layup.
     
  9. rxcomposite
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    rxcomposite Senior Member

    Bryson_As I have said the CSM is cosmetic. The WR thickness I gave you is the minimum allowed, If you sand thru or damage the fibers of WR good luck.

    If you are going to paint it, sanding primer will do in lieu of CSM. Just depend on how good you want your boat to look.

    If contact molded, anything less than 300 gr CSM after gelcoat will do. Even veil cloth will.

    The inner or sole serves the same purpose. If you scuff it thru regular wear and tear, just reglass it or use carpet or glue skid plates.
     
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  10. bryson
    Joined: Dec 2018
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    bryson Junior Member

    Thank you! I will add an extra layer to the exterior to achieve the 3.0mm skin thickness.
     
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