Fixing a piece of plastic

Discussion in 'The Garage' started by petzi-baer, Feb 3, 2013.

  1. petzi-baer

    petzi-baer Been here awhile

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    So, I had a broken piece plastic - a smaller part of the fairing on my BMW F800GS. It's part of the Toura-tech tank setup.

    I bought a new pieces, but broke that one when I tried to install it. It's actually pretty flimsy.

    [​IMG]


    Rather than buying another part which would set me off another 110 bucks, I would like to fix and wonder what my options are.

    I would try strengthen the backside of the plastic.

    thanks

    petzi-baer
    #1
  2. H96669

    H96669 A proud pragmatist.

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  3. Bounder

    Bounder ExternallyDisplaced

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    Some fine stainless steel mesh and JB weld.
    Cut and form the mesh to fit the area ,apply the JB weld to the area around the crack and then push the mesh into the weld then apply the rest of the JB weld onto the mesh making sure it goes right in and saturates the mesh.
    You may need to clamp the mesh down if you haven't shaped it correctly.
    #3
  4. jbhawley

    jbhawley WTF- Gus?

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    is the plastic you want to repair ABS plastic? If so you can solvent weld it back together with ABS Cement...sort of like PVC glue. Its about 4$ a can and works wonders. I just repaired a broken ABS fairing. The problem with JB weld and the like is that it doesn't "bite"into the plastic and will eventually just peel off, same with bondo type fiberglass repair. You can also use the ABS cement to beef-up the back side of a weak piece. I did.

    Here is a good how-to if your interested:
    http://faq.ninja250.org/wiki/Plastics_repair_with_ABS_cement
    #4
  5. kantuckid

    kantuckid Long timer

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    Look for the symbol cast into the back of a plastic part stating what type it might be. Then research the best way to repair that type plastic. Sometimes its solvent other times heat welding or epoxies,etc.. Some of the box store plastic repair epoxy these days is good stuff. You can also use fiberglass cloth if an epoxy is the right way to repair. Why not call the seller 1st and ask about the "flimsy part"? They need to hear problems & might have that part?
    #5
  6. Irish John

    Irish John Been here awhile

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    I have had good luck with a inexpensive plastic welder I bought at Harbor Freight. It is basically a soldering iron with flat tips and sticks of various types of plastic. I have used it to repair the fairing on my club racing bike, the radiator shrouds on my KLR, fairing on my VFR and numerable other items. Pretty easy to use, I found best results by pre-heating the repair by cutting in a groove following the crack which fuses the two parts back together. Then go back over it and back fill with the plastic rod.

    Cosmetically this works best if you can do it on the back side of the part. Generally the repair draws the pieces together close enough that the crack is barely noticeable. I have also used this technique on the visible side of a part. If you take your time and are going to repaint the part, it can look really nice.
    #6
  7. The PacRat

    The PacRat I'm that other guy

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    If it IS ABS then you can grind up some scrap ABS and add it to a jar with some acetone. It will melt into a goo that will essentially weld the plastic back together and bond directly to it. Add metal screen as previously suggested for strength.
    #7
  8. Andyvh1959

    Andyvh1959 Cheesehead Klompen

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    Check out plastifix.com

    A friend who specializes in Honda CX twins claims the site has an adhesive or plastic welding option for all the plastics common to motorcycles.
    #8
  9. kantuckid

    kantuckid Long timer

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    On heat weldable plastics I use a cheap elec soldering gun with the spade tip and a spray bottle of water at hand to solidify the previously welded sections as you work. I had a HF air welder that I tried once & sold, preferring this method. When I was doing wrecks I would save broken plastics of various kinds as "welding sticks" to add to missing areas or build up the back side of repair area. The plastic rods that HF provides don't seem to cover many of the common plastics I ran into on autos. Some plastics prove to be easy , others hard to repair. I just used some clear & cheap epoxy to do a minor repair on an Asian vintage signal lens this week.
    #9