can anyone guess at what went wrong? Can peel fiberglass laminate off? 2-part epoxy

Discussion in 'Boatbuilding' started by leaky, Jun 6, 2011.

  1. leaky
    Joined: Sep 2008
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    leaky Senior Member

    Hi,

    Finishing off a huge project I did with System III Silvertip, I switched from a very heavy stitched matt+woven, to some very light (like 4 ounce) but dense (ie fine weave with only very very small holes) 12 inch woven tape I just happen to have hanging around. No idea exactly what the tape is, got it in a pile of fiberglass stuff a buddy gave me, was a brand new roll. Just seemed like the right stuff.

    The tape was run on a relatively flat vertical surface to re-enforce an area and as part of finishing. Without any doubt I prepped the area perfectly.

    When I laid it up I rolled some epoxy on first, let it setup a bit so it was sticky, then spread the tape out with a squeegee, then wet it out until it went absolutely clear with a roller.

    On some of the "tag" edges that extrude past the area (didn't trim them beforehand) I found I can just peel the cloth off, once I get it started I can just keep working at it and bit by bit it turns white and will come free without much trouble..

    What's left behind is 2-part epoxy on the surface with the pattern of the weave. The cloth I'm pulling off ends up looking dry, although it certainly wasn't before it setup and before I started tearing it off..

    It's like the epoxy won't bond to the cloth? Any idea what the hell is going on?

    Thanks,

    Jon
     
  2. gypsy28
    Joined: Mar 2010
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    gypsy28 Senior Member

    Sounds like peelply to me?
    any pics?
     
  3. leaky
    Joined: Sep 2008
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    leaky Senior Member

    Hi,

    Sorry, no pics, searching for "peelply".. not sure what that is?

    Boat is someplace else, what do you want to see? Maybe I can explain it.

    Thanks you very much,

    Jon
     
  4. leaky
    Joined: Sep 2008
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    leaky Senior Member

    Ouch!

    You know I thought about whether it could be some form of release fabric (ie for vac bagging) but I wrote it off 'cause I thought they were always different colors..

    Does peel ply look like a very fine mesh cloth? This stuff looks identical to a fiberglass used for building other than it's very thin with a very fine nice weave (ie thought it would be great for a finish layer), and is somewhat silky in nature (like a hi thread count sheet compared to a cheap one)..

    Thanks,

    Jon
     
  5. sabahcat
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    sabahcat Senior Member

  6. leaky
    Joined: Sep 2008
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    leaky Senior Member

    I can't tell exactly from the pictures, but thinking this may be Dacron peel ply..

    Could it look like a thin, tight-woven, 12-inch fiberglass tape?

    Thanks,

    Jon

    PS: at least if this is the case it will be simple enough to remove!
     
  7. AndrewK
    Joined: Mar 2007
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    AndrewK Senior Member

    put a heat gun or a match to it, peel ply will melt, glass will not.
     
  8. Phil Locker
    Joined: Oct 2004
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    Phil Locker Junior Member

    There are very fine weave fiberglasses (Satin weave, if I've got my term right) that are quite difficult to wet out and have low peel strength... they've been known to be used as peel ply in certain situations.
     

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  9. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    If you're left with a sound bond on the wetout coats, but easy peel of the fabrics, you've probably gotten a blush between the two, which will easily cause this condition. I don't know if Silver tip is blush resistant or not, but no epoxy is completely blush proof. They all will blush with the right conditions.

    Most of the time when this happens it's surface prep, but you have a solid (my assumption) epoxy wetout coat, but a lack of bond strength with the fabric.

    Lastly, if it was peel ply, it worked perfectly for what it is. When in doubt, don't use a material.
     
  10. leaky
    Joined: Sep 2008
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    leaky Senior Member

    "Satin Weave" would definitely describe this stuff, it's different than typical light woven, much softer and finer weave. Because the weave is so nice, I thought it would be better for cosmetic reasons.

    For sure whatever the stuff is, I'm done with it. The roll is going in the garbage tonight! Glad I noticed this before doing much with it.

    I'm quite sure it's not prep. Silvertip is supposed to be blush-free anyway, but I've been treating it as if it became covered in oil once dried. Because of other details I was doing, the particular area got an alcohol wipe, then a 60 grit sand, then a wash, then an 80 grit sand, then a rinse, and was totally dry.

    Mostly trying to figure out what's causing the failure, then secondly whether I should be removing all of it, or just what obviously isn't bonding right. In certain areas it appears it *might* be bonded, or at least I can't easily find a way to slip a knife under it because the epoxy is thick beyond the edge of the cloth.

    Going to try the burn test tonight, that may give me some clue. Regardless going to try and peel it all off; then the area is getting a 40 grit wheel to remove any which is left plus that layer of epoxy.

    Jon
     
  11. Landlubber
    Joined: Jun 2007
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    Landlubber Senior Member

    I suspect that the tape may be what I use for electrical work sometimes, it is the same description, certainly looks like glass fibre tape, but is in fact NOT a glass tape (cos you can burn it). Try a bit to see if it burns......
     
  12. whitepointer23

    whitepointer23 Previous Member

    i hear peel ply mentioned quite a bit, what is it and what is it used for. sorry to hijack the thread.
     
  13. CatBuilder

    CatBuilder Previous Member

    That sounds a lot like peel ply to me as well.

    I'm working with the same epoxy system and have never seen a blush. They claim, "no blush" but as PAR mentions, apparently, this is only a claim. After building an entire hull from SilverTip, I haven't seen any blush in my case, though.

    Another thought is that it is possible the binder on the fabric was not compatible with epoxy? Maybe. Just a thought.

    Sounds a lot like peel ply though.

    Whitepointer: Peel ply is used to flatten and smooth the surface of a layup. It helps keep some epoxy between the weave of the fabric so that overall, the finished product is nearly smooth. I'm not a big fan of the stuff. It doesn't seem worth the cost or extra weight, IMO, even though I bought a bunch of it. (Bog is lighter than neat epoxy when filling in a weave). One thing I do like peel ply for is protecting your work from contamination or other epoxy work spills. When laying up the inside of my hulls, I do the lowest, center point first, so I have "sidewalk" of peel ply to use when laying up the other parts. I spill tons of bog and stuff on the peel ply side walk, but it's easy to clean up since it peels right off when you are done.
     
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  14. themanshed
    Joined: Sep 2009
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    themanshed Senior Member

    Peel Ply is what it's name say it is to peel off. I use it when doing vacuum bagging. The peel ply goes over the outer surface of your upper most layer of laminate. Then on top of the peel ply a bleeder cloth. Some people will put a thin layer of plastic 2-3 mills with many close holes in between the peel ply and bleeder cloth to keep the bleeder cloth and peel ply from sticking together. Then your vacuum bag goes over top of everything and gets sealed with the vacuum hose leading out of the bag. When the air is sucked out every gets compressed down to the laminate forcing the extra resin / epoxy through the peel ply into the bleeder cloth when the excess is collected and feed though the vacuum hose to an overflow tank if too wet. So the peel ply servers two purposes to release from the laminate and allow your resin / epoxy to flow through the weave. Most peel ply has a no stick finish to it. Sometime it is like skinning a gorilla to get the peel ply and bleeder cloth off after the resin / epoxy has catalyzed. Don’t throw it away send it to me the stuff is not cheap!

    Here is a little on vacuum bagging: http://themanshed.net/tms-20-trimaran/3-1-10-port-side-of-main-hull/?g2_page=2
     

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  15. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Well, it's hard to see, especially it you haven't had much experience with it. Knowing what I know of your building conditions, you should always assume you have a blush. This is the case for most back yard builders.
     
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