I got a bit off hobby last week. I had a track day planned for Roebling Road in Savannah, GA and wanted to paint up my helmet. I'm tired of the basic black, white, or silver. So, I attempted to paint mine up similar to my car color.
If you ever plan to do this to a helmet, YOU MUST mask everywhere the spray may get to the liner. Else, the spray will eat away the styrofoam liner rendering the helmet useless.
Starting with my silver Stilo Rally Helmet, I sanded it down, masked off the rubber trim and padding, and primed it white. Letting it sit overnight I then used Tamiya 3/4" masking tape. I lined up three rows and marked it every 3/4" with a vertical line. I very carefully laid each one down onto the helmet, beginning with the middle piece as shown. The Tamiya tape is the savior here. It is just tacky enough to stick, but not too much where it will peel the paint off.
Using a flexible metal ruler, I carefully cut the tape along the vertical lines I made and removed every other piece. After that step, I sprayed it black, added an extra 1/2" piece of tape to the sides and masked it all.
That is when I proceeded to paint the helmet the main color. Using Tamiyas Racing Blue spray cans, I went through 3 of them to get a thorough coat.
I let that sit untouched for an hour before removing the centerline of tape that you can see at the top of the helmet above.
To protect the helmet, I gave it acouple coats of Testors Gloss and then several more coats of Krylon Polyurethane to protect it. Word of caution with the Krylon spray: you must be careful to not let it build up, it must be thin even layers. Otherwise, the colors underneath will yellow. Nice if you want something to look antique, not if you want a sharp white.
The final outcome. Once I precut the masking tape away from the helmet, there was still some spots where you can see the white primer. This can be fixed with a slight black edging to blend it with the rubber border. I should have done this a month ago, not three days prior. It came out nice and many thought I used a sticker for the checkerboard.
Oh yeah, here's my ride!