Advice paint motorcycle fairings? Last attempt is cracking

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PostPosted: Mon May 08, 2017 9:37 pm
Hi all, I'm looking for some advice painting a motorcycle. I painted it 3 years ago using HOK products. KD3000 epoxy primer, tangelo base coat, and UC35 clear coat. Now it seems like on various spots on the plastic, it is cracking. Some are small cracks, one is a long split down to the plastic along the tail fairing. I'm thinking either the epoxy was sprayed too thick, or it's just too brittle. I have half a quart of the tangelo left, so I'm thinking of redoing it... What would you recommend doing differently on round two?



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PostPosted: Tue May 09, 2017 6:40 am
Pictures would help diagnose the failure.

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PostPosted: Tue May 09, 2017 9:17 am
Yeah, pics. would help a lot on this.... What year/model bike?
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PostPosted: Tue May 09, 2017 9:17 pm
The bike is a 1999 Honda VTR1000F Superhawk.

Here are a couple pics. Three from the tail fairing, and one from the front fender. Most cracks seem to be near a bolt, or edges.

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PostPosted: Tue May 09, 2017 10:49 pm
I'd say that "where" they are at is kind of answering the question about why it is failing. The plastic is flexing with hits/use in those areas and your paint film is not flexing with it. Just looking at the paint job itself it looks like the clear coat is kind of thin and rough(or is that the plastic itself that is rough???).....like their wasn't enough clear for proper build/flow out. What kind of gun/compressor set-up did you use? Do you remember how many coats of each process you did?
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PostPosted: Wed May 10, 2017 6:44 am
The plastic itself may be failing as well.



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PostPosted: Wed May 10, 2017 9:19 am
It was a 20 gal compressor with a devilbiss starting line touch up gun. This was my first time using a spray gun, so I wouldn't be surprised if my technique was bad. I think I had the pressure too low when spraying.
I agree it seems like the plastic is flexing and the paint isn't. I'm thinking it was the primer that was way too brittle for plastic. Would another product work better?

The other thing I just remembered, the PO had tried to paint the bike with krylon... I tried to sand most of it off. But maybe missed some.



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PostPosted: Wed May 10, 2017 10:42 am
Yes, the Krylon could deffinitly be a problem.



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PostPosted: Wed May 10, 2017 11:29 am
Maybe I should try repainting one panel and see if it's better. Any recommendations on a good primer to use for this?

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PostPosted: Wed May 10, 2017 9:58 pm
Yeah, that Krylon underneath sure doesn't help. That was a lacquer based material. Not saying this problem is related but I would have wanted to have 100% of that crap sanded off before beginning. So, okay, doing another panel.... If you are shopping local and using a paint jobber PPG stuff is good. They have a few different levels of product ( Shopline, Deltron,etc.) with corresponding regular and high build primers. I'm not a big fan high builds when it comes to something flexing this much. If you shop online the Tamco line here at the storefront (discuss by dropping a pm to Chris) is reasonable stuff. Also online is **********, again just call them and explain what you are running into for a recommended primer that would work better in this application.
Okay, so you are sanding this back...really check to see if those cracks are going down into the plastic. If they are we've got to talk about getting an ID on that plastic and if it needs to be welded and/or reinforced.
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