I have cast up some parts in Smooth-On 305 Polyurethane Resin., which is white. I'd now like to prime them a neutral gray to look for defects, and get ready for color. I have always used "DupliColor" brand sandable auto-primer with few problems. Now I'm having trouble with paint flaking off at the least provocation. Any ideas or suggestions? Yes, I wash the castings before painting.
Carlo
Hi Carlo,
Resein Parts should be beamed sand beforehand, only that removes the Separating Agents completely.
I ran into a similar problem a few years ago, but with a different brand of paint. The manufacturer had modified the formula, and it was no longer recommended as "plastic compatible".