Katana Chin fairing repair

Discussion in 'Projects' started by RedKat600, Feb 26, 2012.


  1. RedKat600

    RedKat600
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    Vintage Screwball
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    So, this thing had a crack in it when I got it. One of the mounting tabs on the frame is bent. I said F it, deal with it later. Well, now is that later. It's winter, it's parked, carbs are dialed in, fender eliminator done, let's finish this right!

    I tried the repair first with just ABS cement. The fairings are just ABS after all. After talking with a friend, I determined I didn't let it set nearly long enough before I played with it and it didn't hold. After that, I got out my 2 part epoxy in a dual syringe with a 3 hour cure time, and I got to work. Oh, and it was snowing today so I broke out my trusty Halogen lights to use as heaters.

    The paint is not done yet, that's just one coat of gloss, to be followed with another coat, wetsand, another coat, and then possibly wetsand again before the clear. We'll see how it looks after the last black coat. I didn't want to match the factory red/metallic/pearl, so I went with just plain old black.

    The red line is approximately where it was cracked. My phone was charging when I started so no before pic.

    [​IMG]

    Routed, ready for epoxy. Inner side of fairing. Outside is taped along the crack with blue painters tape to hold it together.

    [​IMG]

    All gooped up! Now to hurry up and wait.

    [​IMG]

    Outside is routed and filled now.

    [​IMG]

    Thought I'd paint the uncracked half while I waited. Not too bad!

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    [​IMG]

    [​IMG]

    Tra de la de la......a few hours later, and I sanded the epoxied half. Two rounds of spot putty later it felt and looked good. I used a coat of black primer, followed by two coats of high fill body primer, then a single coat of black. Crack? What crack!

    [​IMG]

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    After I do the clear I'll post up some final pics. Both pieces are going to dry overnight before I attempt to sand them. BRRRRRR!

    Yes, I see the specks in the paint. Those are from the primer, NOT the topcoat. That will be sanded out before the next layer of topcoat and clear. It's dust off my coveralls. Couldn't take them off it was too cold, so I dealt with it lol.
     
  2. KATaTonic3

    KATaTonic3
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    All I had to do was sit back and enjoy the show :popcorn:
     
  3. Andy Capp

    Andy Capp
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    Nice! From experience, it is always worth drilling the root of the crack :secret:
     
  4. james1300

    james1300
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    Cool Post!
    What are all the shiney marks on the black fairing?(primer) Is it due to the bits being too cold?
    What kind of paint did you use?
    How was it applied?(gun or can)
    Great post!
     
  5. RedKat600

    RedKat600
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    Hmmmm....let's hope from my experience I don't have to re-do this one. Thanks for the heads up.


    There are no primer pictures. So that is the gloss black with the halogen lights on it to cure it out in a decent amount of time. The little specks are bits of dust off my coveralls. It was too cold to go without them, so I'll sand them out later. The first coat they are sitting on that small barrel, then the next coat they will be hanging to prevent dust like that.

    Applied with a can. Wishing now I had taken more pics of the glaze putty work and stuff, but ah well.
     
  6. RedKat600

    RedKat600
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    Maybe I should also mention that I "broke the glaze" on the factory clear coat with 80 grit paper, and took it down to ABS with the same on the broken area. After that, it was 150 grit to smooth out the marks, yet still give something for the paint to bite to.

    For the wetsand, I have 240 and 400 grit. I think the 400 might not be enough for the paint or clear to bite on, but I would like an opinion on that for the clear coat. 240 or 400 before the clear?
     
  7. james1300

    james1300
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    What kind of temps where you painting in?
    How long did the paint take to cure?
    What brand paint do you use?
    Keep it up!
     
  8. RedKat600

    RedKat600
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    Let's say my shop has no heat, and it was snowing outside while I was painting! I'm gonna guess between 35-40 degrees.

    The primer took maybe 30 minutes to cure, but it was on that barrel and I had to rotate it under the light to keep it warm. The gloss I have no idea as I put it on at about 5 PM yesterday, and I'm not touching it until this evening.

    That is just regular plain old Krylon. The primer was another brand of automotive High Fill Sandable primer that I can't remember off the top of my head. It was left over from another project last year.
     
  9. RideMotto

    RideMotto
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    Nice post and good work in a cold shop. Can't wait to see the final pictures.

    Absolutely! It eliminates the stress concentration at the leading edge of the crack.
     
  10. Andy Capp

    Andy Capp
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    Check the directions on the clear but you should be able to use 600 grit. 240 scratches will not look so good. Ideally no sanding before clear.

    Crack root drilling relieves the residual stress in any material and creates a round edge that discourages further tearing. Yes, after repeated test flexing mine started to creep.

    Although others have had success with epoxy I know, without filler, epoxy fillets can be relatively brittle. Straight epoxy does also not chemically interfer with the bonding material either. The "plastic weld" epoxies suitable for abs have solvents in them to help create a better bond.

    The other thing I did was to adhere, using the same plastic weld adhesive, an overlapping piece of fly screen repair mesh (with the adhesive backing removed) to the back side for added strength. Worked a treat!
     
    #10 Andy Capp, Feb 27, 2012
    Last edited: Feb 27, 2012
  11. RedKat600

    RedKat600
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    Yeah, I'm shooting for no sanding before clear. I will sand the black and put on another coat with hopefully no dust. The wife may not be picky, but I like to do quality work.

    This is a thixotopric (filler) epoxy that is supposed to stay flexible. We shall see about the bond. Live and learn, this is all a big experiment anyway. Never done fairing repair before!

    I didn't even think of drilling the end of the crack, I should know better by now. I think with this repair and then relieving the stress of the bent mounting bracket SHOULD be ok, but eh, ya never know!

    Hmmm.....I have some mesh in my shop. Some of that with ABS cement might work!
     
  12. Mrmat25

    Mrmat25
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    When your done with your project Jen is recruiting for someone to show her how to put her heated grips on.
     
  13. RedKat600

    RedKat600
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    crackup: crackup: crackup: :mfclap:
     
  14. RedKat600

    RedKat600
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    So, I wet sanded both pieces lat night with 400 grit. Washed them off with ONLY water (well water) in my sink, patted dry with a nice towel and then sat them in front of my stove to dry fully.

    Go out to the shop hang one up, spray it, AWESOME!! Nice thin coat, hardly any peel, looking good. Spray the second one. 2 minutes later, no bueno. For some reason parts of it are wrinkling. I didn't take any pics of the wet sanding because I was not going ot handle my phone while I was wet sanding. I'll get some pics this morning of the paint though.
     
  15. Wrench

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    Wrinkling because the solvents in the Clear attacked the color coat.

    This happens with rattle-can paint; nearly unavoidable once the rattle can paint is outside the top-coating time window. This basically means that if you want it clearcoated, you could not let it cure and wet sand it first; it would have to be shot the same time as the color.
     
    #15 Wrench, Feb 29, 2012
    Last edited: Feb 29, 2012
  16. Fast Eddie 919

    Fast Eddie 919
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    That epoxy fix looks good, I've done some plastic welding, I'd like to try the epoxy deal and see which I like best.
     
  17. RedKat600

    RedKat600
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    Nope, this was a reshoot of the base coat, no clear invovled. I think I rubbed it on my coveralls between the house and the shop. Only thing I can figure.

    Pics incoming.
     
  18. RedKat600

    RedKat600
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    Lookin good for the most part!

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    Then it's WTF is that?

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    Crack shot. Wait, what crack?

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    [​IMG]
     
  19. RedKat600

    RedKat600
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    Yeah, I'll keep you posted on how it holds up. If mine cracks, it'll save you the trouble. I treated the epoxy like bondo and it worked fine for me.
     
  20. Wes206

    Wes206
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    If anyone has to repair a cracked fairing again use Marine-Tex. The stuff is invincible, it's made for repairing boat hulls but I have used it on fairings before.

    Edit: it's sandable to.
     
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