Release film and peel ply

Discussion in 'Fiberglass and Composite Boat Building' started by weldandglass, Mar 15, 2011.

  1. weldandglass
    Joined: May 2010
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    Location: Gulf Coast of Texas

    weldandglass Junior Member

    I'm planning on using a Dahlar release film and Econoply peel ply from airtech to vacuum bag some epoxy laminates. Do I have to use both these layers (along with breather material and vacuum bag) or can either the release film or peel ply be left out?
     
    Last edited: Mar 15, 2011
  2. KnottyBuoyz
    Joined: Jul 2006
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    Location: Iroquois, Ontario

    KnottyBuoyz Provocateur & Raconteur

    Kinda depends on what you're going to do with the panel after. If you're going to paint it use the release film, less sanding. If you're going to do something else like fair it or glue other stuff to it use the peel ply, it'll leave a nice textured surface ready for secondary bonding. You don't need both IMHO.
     
  3. weldandglass
    Joined: May 2010
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    Location: Gulf Coast of Texas

    weldandglass Junior Member

    Knotty:
    Thanks for the reply. All the initial pieces I'm doing will have have things bonded to them so I guess I'm better off using the peel ply. I guess my question is will the peel ply by itself give me enough resin retention in the laminate if I'm using a low viscosity epoxy and drawing around 25 inches of Hg?
     
  4. KnottyBuoyz
    Joined: Jul 2006
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    Location: Iroquois, Ontario

    KnottyBuoyz Provocateur & Raconteur

    There's a few factors there that'd just make it guess work. Some depends on the courseness of your peel ply. Some are very fine weave and don't leave much "teeth" for a secondary bond. I always recommend you do a test panel first.
     
  5. idkfa
    Joined: Sep 2005
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    idkfa Senior Member

    Measured mine, weave is about 1mm wide, is this course or fine? The panel test, should feel like a 60grit sand paper?

    tks
     
  6. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    My best guess is that you will end up with a pretty dry laminate.

    For a start, I recommend:

    P3 perforation
    15 Hg vacuum

    or
    P31 perforation
    20 Hg vacuum

    What do you have?
     
  7. weldandglass
    Joined: May 2010
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    Location: Gulf Coast of Texas

    weldandglass Junior Member

    I weighed my panel after just using the peel ply (no release film) and after calculating what the core and glass should have weighed (using exact size of panel from my cad file and calculating glass and core weight based on manufacturer specified density) and subtracting that number from the actual panel weight, I get a glass to resin ratio of almost exactly 65/35. This seems pretty ideal but I feel like I need to weigh the core and glass prior to bagging so I'm feeling with actual weights and not theoretical. Is there any other way of verifying actual resin content?
     

  8. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    Yes, but only by destruction. You can burn the resin out of the glass.

    Making a test panel is probably the easiest way. The possible error you make is not that big.
     
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