Fabricating custom fairings

Discussion in 'The Garage' started by Bob Tosi, Feb 25, 2011.

  1. Bob Tosi

    Bob Tosi Long timer

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    this is what I dont want:
    [​IMG]

    [​IMG]


    What Im trying to fix:

    [​IMG]

    [​IMG]
    #21
  2. HickOnACrick

    HickOnACrick Groovinator

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    I guess one of the first things you need to ask yourself is whether you want a rally cluster (roll map, gps, rolling odometers, etc) or if you want to keep your stock instrument cluster and just add some gadgets.

    If you want a rally cluster, I think you will need to build a new headlight/cluster frame, then build your fairing around the frame.

    If you just want some room to add gadgets to the stock instrument cluster, and you are going to keep the stock headlamps, then the process will be much easier.

    Although you may not like the aesthetics of the bolted-on windshield, I think that might be a place to start. It looks like the stock fairing is made of multiple pieces. Maybe you can take off the piece that surrounds the headlamps and holds your windshield - I'll call it "the nose" for simplicity. Remove the windshield from the nose, then use the nose as the beginning of your plug. The nose has the advantage of already being drilled for attachment.

    Lay the nose, facing up, on a flat, smooth surface (like a cheap plastic cutting board from a dollar store), and secure it to the board with non-hardening model clay (plasticene at hobby lobby for a couple bucks).

    Now use your choice of modeling media to create your plug. Advantages/disadvantages to media include:
    - Wafer board - easy to cut, easy to maintain symmetry, cheap, light, easy to use as a template for other media, readily available, but it only facilitates flat surfaces and sharp angles, and it will dissolve when exposed to polyester resins.
    - Styrofoam - easy to cut, difficult to fix mistakes, light, cheap, can be molded into any shape, but dissolves when exposed to polyester.
    - Wood - kinda cheap, easy to obtain, can be made into any shape with the right tools, requires much more time to shape, easy to maintain symmetry as mirror images can be cut and then pasted together, will handle polyester or epoxy resins, as a plug it is durable enough to be used multiple times, comes in a variety of hardness that can be glued together
    - Metal - expensive, hard to work with, requires welding skills to stick pieces together, need a variety of special tools or a machinist, once you have your plug, it will last a lifetime and it will yield the best results to a mold, with the easiest "pull" characteristics.
    - Bondo - more expensive than wood, requires tons of sanding, readily available almost anywhere (Home Depot, AutoZone, Wal Mart), does not have good "pull" characteristics, the plug will likely only survive one mold making, it will adhere to almost anything. I like to use bondo over wafer board. It's pretty cheap, and the Bondo can be sanded into curves and soft angles even though the wafer board is flat with hard angles. The wafer board will dissolve under bondo, but does so slowly enough that the bondo hardens before the shape is lost.
    - Modeling clay - pretty expensive to do a large piece. The self-hardening clay cracks when it dries, the non-hardening clay has terrible "pull" characteristics. It is really hard to maintain symmetry with big pieces, but it is very easy to work with and mistakes can be easily fixed. I use non-hardening clay a lot to "fix" mistakes made in other media and to soften transitions between media. It can also be used to add small detail easily. It is also invaluable at holding your plug flat while you work. It can be covered with epoxy resin or polyester resin, but requires more layers than other media, because it is soft.

    One more piece of advice for plugs: Try and avoid any angles that go toward the center of the plug. That is to say, if you are looking at your plug from above, and the angle you are making goes toward the center of the plug, you will have a harder time pulling your plug from your mold, as well as any products from your mold. The more dramatic the internal angle, the harder the pull.

    Hope this helps.
    #22
  3. tmotten

    tmotten Lefthand ride Dutchy

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    What you can maybe also do is model up really rough the shape of additional body shape that you want to add to the OEM shape. Make a quick FG mold and fill this with a 2 part expanding foam liquid. Haven't used this stuff yet, but am keen to so I can find out exactly can do. This way you end up with a foam plug with half the OEM shape that you can leave and start shaping the areas that you roughly added to the shape you want. I don't find foam hard to fix mistake with. Just glue a new piece to is and continue. No need to worry about the cracks at the glue joints, because that will get filled with resin later anyway.

    I may be doing this to my finished part if the lack of symmetry annoys me enough to bother.

    Don't really see the issue with the shape you don't want. Unless you're looking for weight reduction.
    #23
  4. Bob Tosi

    Bob Tosi Long timer

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    yes this is pretty much what Im after, but would like to be able to add a roll chart holder for rides that use these.

    So Id like to be able to have a GPS, roll chart, and maybe a trip computer.
    #24
  5. coppertop

    coppertop occasional meanderthal

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    Wear a good fitting dust mask when sanding anything...
    Good ventilation when working with the chemicals...
    Keep the stuff off of your skin, polyester or especially epoxy...

    and I second the stuff above about how much work it is. Not especially hard, but time consuming getting that plug as perfect as possible so the mold will be as perfect as possible, etc. etc. The upside is you can make something totally cool and unique.
    #25