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Thread: K100 1986 fairing repairs

  1. #1
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    K100 1986 fairing repairs

    What is the best material to use when repairing the front fairing? There is damage around the mirror area and the top left molded in mounting nut has broken free.
    The base material is white and looks to have some fiber.

  2. #2
    A bozo on the bus deilenberger's Avatar
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    Repairs I've seen made on the BMW composite fairing parts have generally been done with fiberglas patches for strength, then something like Bondo to get a smooth paintable surface. The trick is to prepare the fairing part so the fiberglas resin has a good clean surface to bond to.. that's usually done on the inside of the fairing where it can't be seen. Then the cracks on the outside are grooved a bit to get rid of flaking/fuzzy edges and filled with bondo - sanded down, spot putty used to fill small imperfections - and painted.
    Don Eilenberger http://www.eilenberger.net
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    Outlander Omega Man's Avatar
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    You don't mention where you are located but if you are near water, a marine supply will be able to help. A good read as to "how to" along with the supplies is Here at West System.
    OM
    "Well they say.. time loves a hero but only time will tell.. If he's real, he's a legend from heaven If he ain't he was sent here from hell" Lowell George
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    I am not an expert, but I have done my share of body work. I also used to work at a marina (which was also a Motorcycle shop) when I was younger.

    Here is what I did this Spring to my bike.

    I redid the styling of an old Luftmeister fairing. I used the standard Bondo brand of fiberglass, with the glass screening (to re-shape and cover over larger holes) and then the Bondo brand "bondo" putty to fill, sand and smooth. Warning, the bondo fiberglass is extremely hard once hardened (be sure to keep the glass cloth BELOW the finish surface as it will not smooth out, but leave marks when sanded) so make sure you build up, and use coarse wet or dry to get down to surface and then finer to finish.

    However, I had my bike painted by a professional shop that does high-end cars and is the local exclusive body shop for the local BMW car dealer.

    When talking to them, the manager suggested I use a product called "Duraglass" when I needed to fill, but not fill with glass and not use the cloth. Then, after building up with Duraglass to surface desired, use the Bondo puttty to fill and smooth and finish sand.

    This Duraglass (sold in a can about the same diameter as a gallon paint can, but only about 3" tall) really worked slick. It is only sold at a auto body paint supplier. You will not find it at any AutoZone or the like. It Saved the messiness of the cloth with the sloppy resin and all that sticky mess. It was still messy, but not as much.

    This dried in about 1/2 hour - ready for the next cote. Worked great and I think would be great for your application. Trick is to be sure your initial surface is very clean and well sanded (not smooth) so fiberglass will stick.

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    Thanks

    I am great full for the replies I have used epoxy for boat repairs and I was uncertain about the base material of the faring. I will try the Duroglass and Bondo
    Cheers Bob

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    Repair started

    After striping the fairing of all parts I found that it had been repaired before. The fiberglass tape used on the inside was not well bonded and just pealed off with no resistance. I will do some tests with different things till I find what bonds well. Starting to get cold so this may take time.
    Cheers Bob

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    Quote Originally Posted by Bob 1642 View Post
    After striping the fairing of all parts I found that it had been repaired before. The fiberglass tape used on the inside was not well bonded and just pealed off with no resistance. I will do some tests with different things till I find what bonds well. Starting to get cold so this may take time.
    Cheers Bob
    My bet was that the guy who did the previous repairs, didn't do a good job of preparation. The bonding surface needs to be "roughed" up with coarse paper, and the larger the surface area the better. The local BMW (auto) body shop also told me that if possible put some holes through the object so that they provide more gripping surface. If the holes are countersunk on the outside, the glass material will harden and can't pull through,

    I also, on hidden surfaces, will use some supports (if necessary for support and if you have room) by using some small pieces of wood. These provide lots of strength so that they help support over the crack/break and the layer of glass doesn't have to bear the whole burden. Also, layering in, if possible, pieces of the glass "cloth" does wonders for strength and spreads out the support pressure.

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