Peel ply....

Discussion in 'Materials' started by Roly, Oct 28, 2006.

  1. Roly
    Joined: Jul 2005
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    Roly Senior Member

    Can anyone give me the low-down on peel ply.
    The do's & do-nots!
    I am using it over epoxy/glass in prep for overlaps,fairing compound,bilge paint,bulkhead tabbing.
    Internal glassing;Hand laminating. I missed using it on the exterior hull glass---expensive time consuming mistake.

    Tips Like price,best place to buy,how long to leave before pulling off etc.
    Cheers.
     
    Last edited: Oct 28, 2006
  2. jonsailor
    Joined: Sep 2005
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    jonsailor Boat designer/builder

    go the pel ply

    There are many styles to buy and some are better for differant reasons.
    You can buy a very coarse one which we use for flat panel bulkheads and tabing joins because it is easier to remain flat on the job without puckering.
    We also use a fine cloth if we have to throw it over a large laminate or a contour one where we cannot pat it down smooth to wet out. This is only used in this sequence where we are vacumm bagging over the top. By using the fine one here, you avoid resin ridges than are more prominant from the coarse one if it is not laid flat.

    We leave the peel ply on until we get to the final finishing stage as this keeps all the **** off the job until you need the final preparation. If we tab a bulkhead into a hull, we just remove the section around the hull for tabing so that the rest can remain clean of foot prints and resin spills. For instance, we will even paint the deck head first so the peel ply acts as a drop sheet for the rest of the yacht. Peel ply is the best thing since sliced bread and gives a good finish with minimal work for secondary bonding.
     
  3. Roly
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    Roly Senior Member

    Awesome---thanks.
    We just wore thru 3 valves, nipples & 8 ceramic nozzles trying to sand blast the shine off 40m^2 of hull. Inexperience on my part. Ended up costing shitloads more than peelply. Plus heaps of time and swear words.
    Sounds brilliant way of keeping your work clean too.
    Mandatory material I reckon. :idea:
     
  4. waikikin
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    waikikin Senior Member

    edge pucker

    We'll often remove the selvedge from the peel ply as it usually lays a lot sweeter like that. Regards from Jeff.
     
  5. John ilett
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    John ilett Senior Member

    We use a peel ply commonly sold as a lining material in clothing. It's called polysheen and is typically much cheaper some peel plys sold by composite suppliers. It's only good for ambient cure resins and not for high temp such as pre pregs. Make sure your layup is slightly wet and quickly throw the peel ply on top and brush it down flat with a bannister brush (from a brush @ pan set) so that it will will moslty wet through from behind. This is easier and faster than trying to wet through the peel ply after. Having said that, apply more resin where needed with a roller rather than a brush.

    Love that peel ply!
     
  6. catmando2
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    catmando2 Malaysia bound....soon

    Have looked at these post's and have to say I hate peel ply. I always seem to end up using excess resin like above post which = weight.

    In the early 90s there were lot's of talk and some problems with peel ply having silicon or similar, making later bonds dodgy and I had witnessed a daggerboard smashed out of a cat with a nice clean fracture where peel ply was used.

    I just wipe a thin bog slurry every where that needs paint or more work done while glass is green. At least then i'm not grinding glass for the next stage , have no contamination and dont spent a fortune on peel ply.

    And Johns comment on the suit liner above is correct, we were using this 20 year's ago as well.

    Dave
     
  7. nero
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    nero Senior Member

    I have found only limited functionality for peel ply in hand layup. I have a roll of perforated light weight peel ply that has a slightly green color. The only use I have found is as a release agent. I use it when pressing seams of overlapping glass on flat pannels.

    The problem I have not over come, is the puckering and trapped air underneath it. All looks wonderfull until I remove the stuff and sand. Then a whole bunch of air bubles appear.

    The other problem is that once the peel ply is on, I can no longer see dry spots or places where the glass has lifted from the core.

    For secondary bonding and finishing, I have started to use an electric power sprayer and a sump pump. This does an excellent job of removing blush from the inside of the hull.

    In areas that I am going to tab in a bulk head, I add a thick layer of resin just after the wet glass has gone tacky. From destruction testing, the results seem to be as strong as the origininal wood core/fiberglass bond.
     
  8. marshmat
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    marshmat Senior Member

    I'm not sure how much value peel plies would have in an open wet layup.
    I have had very good success with Airtech plies in prepreg carbon and kevlar layups. They make release a lot easier, and leave this beautifully textured surface that epoxy just loves to weld itself to later on.
    The same peel plies have also proven useful in vac-bagged wet layups. It is really important when using them to not use too much resin, though. The peel ply's job is to remove the waxes that float to the surface as the resin cures, and to leave enough of a texture, that secondary bonds will hold well. Too much resin in the layup, and the resin will soak right through the peel ply making it nearly impossible to remove. In open layups, covering the whole thing isn't going to accomplish much.
    One option that often works is to lay strips of peel ply only where secondary bonds (ie. bulkheads) are going to go. This works fine in an open layup (no bag), it won't cut down on the weight but it will leave you with a good place to bond the next part.
     
  9. catmando2
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    catmando2 Malaysia bound....soon

    Are any of you guy's actualy doing destruction tests yourselve's , or are you just believing the sales rep?

    Dave
     
  10. marshmat
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    marshmat Senior Member

    I generally do some testing of my own, plus building on the advice of previous team members.... don't take a sales rep's word for anything, sales types often seem to have little knowledge of the actual product, for info on that you need an engineer. But yes, in my experience with prepregs, peel ply is amazing stuff and results in much better secondary bonds than bare laminate does. Same goes for vac-bagged wet lay if you're smart with the layup. I haven't done much with peel ply on open wet layups so I can't speak to its effectiveness there, although with so much excess resin I doubt it'd be as effective.
     
  11. Pericles
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    Pericles Senior Member

    Has anyone experimented with stretching industrial strength wrapping film over the last coat of epoxy on a boat hull? Would it bond to the resin or would it pull off leaving a smooth high gloss finish without runs?

    Pericles
     
  12. lewisboats
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    lewisboats Obsessed Member

  13. cookiesa
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    cookiesa Senior Member

    Hmmm I like :)

    I'm going to have a painted finish most likely... (easier to hide mistakes... my woodworking is not to a carpenters standard!)

    Would I be right in thinking with this "gloss" finish a light sand for the paint to key in with maybe all that isrequired in the bulk of areas? (Thinking external parts of the hulls) Of course there is likely to be areas that need more work as I don't think I'd get close to that kind of finish on all the areas!
     
  14. rxcomposite
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    rxcomposite Senior Member

    Looks like a 0.003" thick plastic. A 0.030" is 30 mils and is thick as an illustration board.
     

  15. Pericles
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    Pericles Senior Member

    cookiesa,

    Yes, light sanding is all that is necessary for painted finish. The film gives you the opportunity to miss much of the long boarding inherent in hand laid epoxy composite construction.

    Cut the film to match panel shapes before pouring the epoxy, ensure correct wet out & bed the film per John Blazy's instructions. Do the work methodically in sections & allow each to cure before moving on, i.e. bottom one day, sides the next. Use masking tape will hold the film in place as necessary. Work smart, not hard. Google Polyethylene Terephthalate, often referred to as PET film but commonly known as Polyester PET.

    P
     
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