Any Carbon/Kevlar Skinning experience in the group?

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by Rellik, Apr 28, 2010.

  1. Rellik

    Rellik o-KAY!

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    Admittedly, my bike spends a significant amount of time doing this....

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    These are not fast sliding falls, but rather hard sharp falls.

    With that in mind, I am looking to "skin" or apply a layer or two of 2x2 twill carbon/kevlar mix over my upper fairings and eventually move on to the tanks and rear panels. I am leaning towards the mixed twill as it will offer tremendous light-weight strength and yet provide more flex than the carbon alone. I am looking for any experience anyone has had in the following areas:

    A: How well does the epoxy bond with the ABS. I fully grasp the need for proper prep, but should I put some kind of adhesion promoter on the plastic first? My local supplier says the part will shatter before there is any worry of just the epoxy to plastic bond letting go.

    B: What are the concerns with expansion of the tank if I apply an immovable skin on the exposed outer surface. The sides and inside surfaces will still be able to expand and contract.

    C: What are the secrets to cutting the fabric around holes such as this one...

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    I am not looking to press the material into the hole, but rather stop just short all around.


    As I am going for material strength more than the carbon fiber look, the epoxy will contain the final color pigment (likely black) so that the orientation of the fiber won't be of concern.

    That's all for now, but I'm sure there will be many other ?'s!

    Thanks,

    Alan

    #1
  2. K2m

    K2m ....58....

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    I would leave the plastic for that job. You will end up breaking it if you cover it as it needs to flex.

    I would make up some good thick protection for the bottom of the tank.

    You can make nice mounts in carbon.

    I don't care either about the finish as you are doing it for your self. Form follows Function. But I recon I nailed it anyhow in the looks department anyhow .......:lol3
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  3. Rellik

    Rellik o-KAY!

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    Thanks K2m, you definitely seem to have some experience!

    The flexing is the reason behind the carbon kevlar mix. It allows some flex compared to the carbon alone. I'm not sure how much this part needs to flex anyways.

    Alan
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  4. Geek

    Geek oot & aboot

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    Please keep us updated on your skinning progress.

    I'm buying all the "commercial" carbon skinned parts I can get (as money allows) but I'd also love to mold some of my own for the bits not available...

    :lurk
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  5. K2m

    K2m ....58....

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    If you polish,wax, your faring, then apply 3 layers of carbon... West system epoxy......... Pop it off and use it as a mold you could make as many faring pieces as you need.... And get not to bad a carbon looking finish as well (look at the inside of my tank protectors) You could also make one into a water tank........

    You are only limited by your imagination, or like me .... Time...... If I wasn't married I would have all these things. :freaky

    I want to make a copy of this for my super moto look:eek1

    I have many parts that I bolt on depending on where I am going......

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  6. Pete640

    Pete640 I hate sand.......

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    Rellik - be careful moulding off painted parts using wax as the heat from the resin (exotherm)can cause it to melt the wax and adhere to the part. I've seen this happen a number of times with people hiring cars for their spoilers/body kits and having to pay for the panel beating and associated costs - it was a good idea at the time. Ive got both fairings moulded if your interested (pm me) .as well as most others
    As for the CF/K twill its a good blend but kevlar will lose its properties if left exposed to uv light (sunlight) It needs to be covered by paint or other fabrics. The ones you see commercially are usually bling factor or dyed CF - either way if your making it for its strength then you have to do it right.

    Pete:1drink
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  7. K2m

    K2m ....58....

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    You should see...... Pete's work:eek1

    He is one of a few technical assets here...... Thanks for coming in Pete

    Have a laugh at the way I do it........ :lol3 Sticky tape

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  8. Rellik

    Rellik o-KAY!

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    I was hoping that the pigment in the epoxy would solve that problem. Do you agree? Also, do you agree with K2m that the straight carbon fiber would be too rigid?

    Thanks
    #8
  9. GoNOW

    GoNOW Long timer

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    I have been thinking of getting huge sheet of vacuum formed plastic that will cover the entire tank. They make some thick, high impact stuff. Anyone try this?
    #9
  10. a$$hole

    a$$hole Long timer

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    Or just like 6 layers of 3m vinyl:D
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  11. Pete640

    Pete640 I hate sand.......

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    Pigment in the epoxy - AFAIK it doesnt have any until you add it??? You'll have to explain that one better.
    CF by its nature is extremely rigid - no flex which is why it is both good and bad. Good in that it resists bending or movement way past normal glass cloth - but when it reaches failure its good night irene. Just look at the masts on the super maxi yatchs. When they fail they FAIL... That is where the engineering comes into it - using CF/Kevlar/cloth laminates with the appropriate resin system. Kevlar on the other hand...........
    As for the sticky tape - plenty of people use it or cling wrap. Cling wrap in its liquid form is PVA which can be purchased at any good FRP retailer and either wiped on or sprayed (brand dependent) and will turn into a thin film that is both styrene and epoxy resistent. Its easier to use and can be cleaned up with water. You might be better off with that K2M.
    Basically there are a number of pitfalls that can cost you a fair bit if you new to the game - but the interweb has heaps of useful info that can speed you along if you going along the DIY approach.
    Let us know if you have any other questions.

    Pete:1drink
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  12. The Mass

    The Mass Timbuktu or Bust... Both!

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    Hey K2
    Are those rear tanks of yours for water or fuel?
    Any cahnce you can post a couple of pics of them on their own, showing especially the joining method as well as the fillers (where did you get them from?)
    If they are fuel tanks, I presume the resin used was a vinylester and not epoxy?
    Many questions I know, but I am very interested in your work.
    Cheers
    Mass :thumbup
    #12
  13. Pike Bishop

    Pike Bishop Pull Down the Ponzi.

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    Most epoxies (West System, System 3, Raka, MAS, etc.) are unpigmented, and since most epoxies have very little UV resistance, you need to paint them or add a UV blocker (aluminum powder, graphite powder, etc.) to the resin/hardener when they're still liquid. By blocking the UV just like the lead oxide in paint, those materials give the epoxy a lot more sun resistance.

    Kevlar also breaks down with UV exposure.

    Another option you might want to consider is using polyester resin instead of epoxy. It's a little harder to work with (mixing is a little more critical, pot life is typically shorter, and you'll need to either add a wax to the resin or somehow shield it from the air to get it to fully harden on the surface without a tacky film that makes sanding a nightmare) but polyester does have a lot more UV resistance than epoxy.

    I've never messed with anything for my bike, but I've used epoxies, polyester resin, fiberglass, carbon fiber, etc in marine repairs and fabrications. You can do some really cool things once you get the hang of it.

    For specific questions, you might want to contact West System / Gougeon Brothers – those guys really know what they're doing and what they're talking about. They also have a free publication you can subscribe to – Epoxyworks – that has lots of good articles on how-to and projects, both marine and non-marine.

    Good luck.
    #13
  14. K2m

    K2m ....58....

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    Bit busy right now Mass. I'll get back to you........

    I went out and got a good 0 to 400gram scale for critical mixing.....

    Thanks for the contributions fellers..... :clap

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  15. HickOnACrick

    HickOnACrick Groovinator

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    I am watching this thread closely as I want to fab a variety of CF parts as well. One site I came across was this: http://www.carbonmods.com/

    For a beginner, it looks like it might be a good way to get started, then once you get the knack, you can find a place to buy all the stuff individually.
    #15