Replacing teak with Kevlar Laminate

Discussion in 'Fiberglass and Composite Boat Building' started by aalbert, Oct 7, 2010.

  1. aalbert
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    aalbert Junior Member

    I am painting my boat "Kevlar Yellow", and want to recreate my teak trim pieces in Kevlar.

    For trim pieces I am planning on wrapping 4mm H60 strips with mat, glassing with vinylester, running the resulting strips through a table saw or router length wise to clean up the sides, and then laminating the final product with Kevlar and clear UV resistant Epoxy from FGCI.

    For larger pieces, I would just make full laminate pieces using the H60 and Kevlar or Carbon/Kevlar for contrast.

    I know the Kevlar fuzzes up when cut.. Are there any tips to dealing with that issue, or should I just wrap each piece of H60 with Kevlar like a present, and tuck the extra material on the back, so that I can keep clean corners..

    Anyway, any suggestion on how to best implement would be appreciated.
     
  2. Munter
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    Munter Amateur

    I would try to avoid cutting the laminated cloth if possible to avoid risk of fuzz. Also, will the UV resistant epoxy avoid the problem of the kevlar going brown in the sun? There is a huge colour difference between fresh and exposed kevlar so if aesthetics are of prime importance to you this colour change could be important.
     
  3. aalbert
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    aalbert Junior Member

    Yes... the color match is important to me... and I too am worried about how much the Kelvar is going to brown... I am hoping the UV inhibitor in the Epoxy will curb that, but also wonder if there are any other UV additives that can be brought into the mix. I have even considered adding in some dye (can't find any listed that aren't likely to run when subjected to the epoxy, or even doing a light coat of yellow paint, on the fabric to reinforce the yellow (in which case, I might as well use glass and fake it).

    For those areas that require cutting (i.e. mitered corners), can the fibers be rewetted with epoxy and tucked back in (considering they will be hidden by the other mitered side)?

    Any other suggestions out there on how to maintain the color - Would Awlbrite provide additional UV / Color fade protection? If it matters, the material I am using is 4" tape from Fibre Glast
     
  4. Landlubber
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    Landlubber Senior Member

    the Awlbrite is the answer, the epoxy will yellow quite fast, it needs the protection of a UV clear coat.
     
  5. PAR
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    PAR Yacht Designer/Builder

    It's a lot more durable to paint a Kevlar finish onto an object, so that it looks just like Kevlar, then to have an actual clear coat over Kevlar, the same is true of carbon. With no care at all you'll get 10 years or more from a paint job like this (assuming good quality LPU's), but with reasonable care, such as keeping the surface clean and waxed, you can get decades of use from these painted surfaces.
     
  6. aalbert
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    aalbert Junior Member

    So any suggestions on how to Faux Kevlar?

    Landlubber.... The Epoxy from FGCI has a UV inhibitor to keep itself clear, but I got the impression in talking to them, that they don't really warranty it for what is underneath, so I am hoping that maybe Awlbrite might give it that extra protection. Have you by chance used it on Kevlar, or some other UV unstable product? I would be interested in how it protected the core product.
     
  7. Ilan Voyager
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    Ilan Voyager Senior Member

    Par is right: the solution is a paint looking like kevlar.
    You're wasting your time and money if you use true kevlar and epoxy. That will last a very short time, if you can resolve the problem of cutting kevlar neatly.

    UV inhibitors in clear epoxy do not work well, kevlar hates UV and vinylester is not better Special clear varnish just delays the inevitable: epoxy, vinylester and also kevlar do not withstand UV. None clear coat and UV filter is able to stop UV from degrading them. It's lost in advance.

    It exist special "paint" films imitating to perfection carbon, carbon-kevlar and maybe kevlar. Less work, less expensive, more durable. You should look in motorcycles products providers.
     
  8. rxcomposite
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    rxcomposite Senior Member

    Kevlar "wicks" water. Make sure the ends are completely sealed. Epoxy is not UV resistant.
     
  9. Herman
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    Herman Senior Member

    Epoxy, even UV stabilised ones, will yellow over time. They will hardly protect the aramide, and the aramide will turn brown in a couple of weeks in summer. It even changes color remarkably fast in our warehouse, where we have a roll which is used for cutting samples and small quantities. This roll is in a room which has no windows and no light from outside enters!

    For creating "faux" aramide, there are films, which are nice to work with, once you get used to it. I have seen a couple of demontrations, where the film is floated on water, and the object to be covered is pushed through the film, into the water. Water temperature and the size of the waterbath is critical. For the latter the watebath had adjustable slabs of stainless steel, which could be adjusted in length and width, so the piece of film would stay in place. Unfortunately I lost track of the company, but I am sure it can be found on the internet. Perhaps via youtube.
     
  10. PAR
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    PAR Yacht Designer/Builder

    I've done faux carbon fiber that you couldn't tell from the real thing. In fact, in the last decade I've done quite a few, as kids seem to think it looks cool on their cars. I just did an instrument panel for a pontoon boat a month or so ago like this, which I found absolutely hysterical, but a gig is a gig.

    Kevlar I've never actually done, personally, though I've seen it done and it's a similar technique as carbon, depending on the weave type you're looking to simulate.

    In a nut shell the way I do a faux carbon look is a base coat of dark(ish) gray, which is color sanded to remove the sheen, then an applique, which is my special secret, but available at the local "Dollar Store" for cheap is applied over the base coat. This is what masks out the weave pattern then a light coat of gloss black is shot over this. Once dry and the mask removed, then the hard part is candy black pearl is applied in several coats until the look is just right. This is a difficult paint to apply and if you screw up, everything has to come off and you start over, but with some practice, you can get the technique down and charge big bucks for a faux carbon hood, on some bonehead's Honda.

    Fibre Glast has a printed scrim product that can be employed as a finish, though I'm not sure of it's UV tolerance. It's not cheap, but then again neither is Kevlar. I've seen it used as wood grain, stone, etc. so I suspect they also have carbon and Kevlar. Since it's a scrim, it drapes easily.
     
  11. aalbert
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    aalbert Junior Member

    I sent Fibre Glast an email asking if they had a procedure, or any dyes to add into their product... If they have a printed Kevlar scrim, that would be great, but I haven't seen it on their site... Will have to follow up with a phone call to them, to sort things out.

    I have actually also thought about scanning some Kevlar, doing a wrap print, and laminating over the top of that.

    In the end I know it will look kinda "campy" with exposed Kevlar on a center console, but I want to learn how to do it (for the sake of learning), and think it is just a "fun" touch.
     
  12. Herman
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    Herman Senior Member

    You can dye your resin yellow. Use a solvent based dye for that. They use it to dye epoxy hardeners blue, and resin yellow (mixed it will turn green)

    I buy this at a company also making dyes for printing inks.
     
  13. Ilan Voyager
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    Ilan Voyager Senior Member

    The problem is not to dye the resin. The goal is get the look of a Kevlar cloth embedded into clear resin, with the apparent depth of a thick barnish. Like on the motorcycle or car racing pieces. Some did that on kayaks, and the intelligent guys paint immediately over with a good polyurethane as they want to preserve the performances of the kevlar epoxy composite. If not painted, these kayaks look badly after one season, not a problem for the racing guys as they change of kayak as soon it becomes "soft".

    None resin adheres on kevlar, it's simply a mechanical embedding that will get "loose" in short time. That explains why (added to the very poor perfs of kevlar in compression and the price) kevlar is not more used on racing multihulls since a long time.

    Only a varnished film transfert can make a good imitation of carbon. As kevlar is a bit out of fashion, maybe a such tranfert will be difficult to find.
     
  14. PAR
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    PAR Yacht Designer/Builder

    I disagree, I've painted several small and large pieces with a carbon look and you wouldn't be able to tell without a 10x paramag or other optical enhancement, that it was a paint job.
     

  15. rxcomposite
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    rxcomposite Senior Member

    Kevlar is a specialty fabric. The "sizing" or finish on the fiber makes it slide past the resin, not stick to it. The opposite of what is needed for carbon and glass. This is to maximize the material property of Kevlar, which is shear strength.

    Kevlar also wicks water. When the resin is abraded, water enters the Kevlar fiber.

    Kevlar is best used in the center of the laminate, away from the "wet side". This is where also the shear is greatest (neutral axis) where the layer tends to slide past on each other.
     
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