PU paint bubbling
Tuesday 19 December 2000 1:00:00 am
I repainted a used car. The seams around the wheel-wells (which
are spot-welded) commonly give rust,
> so I applied an inorganic zinc-rich coating, and used an epoxy primer on
top of this. I drove the car then
> for about four years, without finishing the paint job, and no sign of
rusting at the seams was evident at all.
> It looked AOK. Then I went ahead and primed and painted the car with a
catalyzed polyurethane automotive paint.
> It looked great for 6 months, but now there is bubbling of the PU paint,
at those seams. Its hard to imagine rusting
> having started at exactly the time I did the final finish. So why does
the PU paint now bubble, and is there a way
> to avoid this next time? K J Strack