Hi everyone, 
My name is Wolf & I'm new to the board.  I do a little bit of casting for people in the custom toy arena and make plastic resin pieces for different projects.  My website is called www.SolarColorDust.com where I offer Color Changing paint pigments for your model cars.  While I mainly create color changing figures for people I have had a lot inquiries about the pigments on model cars, planes and trains so I figured I would try to reach out to anyone in the forum and offer a unique way of painting your custom car.   
I have the largest selection of color changing pigments on the web.  My pigment, Solar Color Dust, changes colors from white to color in sunlight.  I currently have 5 different colors of SCD: red, blue, yellow, orange & purple.   
The second of the two is called Thermal-Dust, where it turns from COLOR to CLEAR when it is put in warm conditions of 86F or warmer; which I carry 15 different cool colors that change colors.  Even the heat from your hand will change the pigment colors. 
 
Please check out my site and see my video demonstrations; I'd be happy to answer any questions you may have  
Wolf 
www.SolarColorDust.com