I am responding to your July 2004 column about “Painting ABS Plastic" (www.pfonline.com/articles/clinics/0704cl_paint1.html). I agree with your basic premise to use a slower solvent. My company probably would cover both routes by blending mineral spirits equal parts (good for oil contamination) and butanol (good for finger prints and stearate type mold release).
I also agree with you that something different is in the black ABS plastic. It bothers me that the paint adheres to natural but not to black—smart paint. I suspect that the problem is the black dispersion that is incorporated into the natural plastic. Often these dispersions are based on polyethylene, which is impossible to paint. It also bothers me that they are priming ABS. There is no reason to prime ABS as topcoats can be made to adhere and not attack the plastic too.
My company’s Analytical Sciences Department could absolutely tell what is on the surface and identify the surface morphology.
I really enjoy your column and read it every month especially as it relates to plastic and composite painting. Maybe in my retirement, I will have the opportunity to be like you! C. S.
Thanks for your comments. You are too kind. For the Painting Clinic reader’s information, C. S. is the person I call to solve plastic-related coating problems.