Ask the Expert Question-and-Answer Archive

by Ron Joseph

June, 2006

Applying CARC Over Rhino Truck Bed Liner Coating

Q. We are a military equipment builder who has had to apply CARC polyurethane paint on top of a "Rhino" coating (basically truck bed liner material) which is also polyurethane. After testing in the field the CARC paint cracks and flakes off. One source told us we should apply the CARC to the Rhino coat while the Rhino coat is still wet. Does this sound right to you?

A. At least the following possibilities exist: Flexibility between the Rhino coating and the CARC might be different; surface tension between the two coatings might be different; the coatings might simply be incompatible; you might be waiting too long after applying the Rhino coating before applying the CARC. In this case the Rhino coating might be fully cured and present an inert surface. However, in that event you could consider abrading the surface to generate a relatively rough profile and achieve physical adhesion between the two coatings. It is possible, (although I hope it is not necessary) that you would need to apply an epoxy primer over the Rhino coating before applying the CARC.

Without knowing more, I can't be more helpful. If you simply can't find a solution to the problem, please get back to me as I might be able to work with you on a consulting basis to resolve the issue.

Best wishes,

Ron Joseph