Sunday, August 30, 2009

Painting a motorcycle

This is the second time that I have painted my motorcycle and I wanted to share a few things that I have learned:

Almost all spray-can paints will not resist spilled gasoline very well. Some are better than others, but all pale in comparison to factory paint.

Almost all spray-can paints will leave a finish that is soft compared to factory paint. This is a problem because dust will get embedded into the finish, and the surface will lose its shine.

Getting a good-looking paint job at home with spray paints is not difficult, but the paint job will not last as many years as a factory paint job.

I briefly explored the possibility of spraying two-part (2-K) urethane paint which is what most car and motorcycle manufacturers use. There were two options: 1. Mix the paint myself and shoot it using an air sprayer (eg an HVLP gun). 2. Get SprayMax 2K in a can: I've heard good things about this paint, but it's very expensive. I would need at least three cans, and for a just a little more money, I could buy a quart of real 2K paint and a cheap HVLP gun from Harbor freight.

In the end, I decided to just use Krylon spray cans for $2.99 each. The motorcycle itself is not the most beautiful machine in the world, and repainting it every 5 years is an acceptable level of maintenance.

The original color was red, and I painted yellow over it without stripping last time. I used Jasco methylene chloride stripper on the steel gas tank.

The tank has a big dent that I filled with bondo before the last paint job

I've shot a few coats of Krylon primer, and used some glazing putty to fill in the last surface imperfections. I wet sanded the primer with 320 grit between coats. This was the only sanding that I did on the gas tank.
I shot about 3 coats of color on the tank, letting each coat dry for a day. Krylon can be re-coated within an hour or after 24 hours. These directions must be followed or the paint will lift and look terrible. It will have to be re-sanded and painted again. I was shooting pretty heavy coats, and I wanted to make sure everything was set before I loaded on more paint.

The plastic fairings on the bike have another problem: The methylene chloride stripper will dissolve the plastic fairing as well as the paint on it! I learned this the hard way the first time I painted the bike. A good alternative is to use regular DOT3 brake fluid on the plastic parts. It doesn't work nearly as well as paint stripper, but it's a lot better than nothing, and it doesn't attack the fairing plastic. Use really coarse steel wool to scrape off the old paint. I sanded starting with 80 grit, and worked up to 320. I did not use primer on the plastic parts -- just shot color right on the plastic.

I shot three heavy coats of color over the course of three days.

After drying another day, I added black stripes. The stripes were masked with blue 3M painter's tape, and the black paint went right over the yellow.

I did not use a clear coat over the color coats.

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