method for wet layup with nomex

Discussion in 'Sailboats' started by Steve Adolph, Apr 22, 2007.

  1. Steve Adolph
    Joined: Dec 2006
    Posts: 3
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    Location: Ottawa

    Steve Adolph New Member

    I've been doing some reading, and I've not been able to find a soup to nuts method to laminate reliably using a wet layup approach with nomex.

    Some of the issues I've seen-

    1) obviously, wet layup of the inner skin can't be done on nomex, so you have to wet out the inner skin on a table first
    2) placing nomex on the outer skin, when the outer skin is wet, can cause epoxy to wick up into the nomex. this is bad because the cloth gets dry and then may be too dry to be watertight.
    3) you have to get enough epoxy onto the nomex to support a good skin bond


    Taking this into account, could the following approach offer good results?

    Step 1. Outer skin
    * prep the layers, place and wet out in the mold. nothing particularly special about this stem

    Step 2. wet out of one side of the nomex
    * (assuming it is already cut and prepped)
    * on the wet out table, over a plastic film, roll out a layer of fresh epoxy
    * place the nomex on the wet epoxy, to get a quantity of epoxy on the nomex edges
    * place the nomex in the mold on the outer skin
    * in some places, you may need some contoured foam strips placed in the mold to terminate edges of the nomex panels, and fair them down smoothly. this will prevent the nomex from collapsing at the edges under vacuum
    * finish off all the nomex placement

    Step 3. vacuum it all down and cure
    * hopefully you have enough epoxy to bond the nomex completely and well, and there is enough epoxy in the outer skin to be completely wetted out

    Step 4. bond in the inner skin
    * prep the core so that the outer skin can be smoothly and continuously bonded
    * prepare the inner skins
    * wet out the skins independantly on the wet out table
    * place the skins on the mold
    * vacuum it down and cure


    With the price of nomex at approx. 2x divinycell, and the price of kevlar at approx 3x glass, you don't want to write off a ton of this experimenting.

    So for you people who have trod this ground before, will this approach work? Any suggestions to improve the technique?

    cheers,
    Steve
     
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