"Bob Engelhardt" wrote in message
news
On 8/31/2017 5:20 PM, wrote:
...
Por 15 is not UV stable. It has to be topcoated.
...

I'm late to the party, but I have some personal experience here.
Back in '03 I painted a trailer frame with POR-15 and did not top
coat it. (An erroneous page on their web site said that it didn't
need to be top coated.)

The POR-15 that is on the part of the frame that is exposed is
intact and there is no rusting there, or anywhere. It will likely
fail sooner than if it was top coated, but I'm pretty satisfied with
the 14 years that I've gotten.

Bob

I ended up brushing a similar Rust Converter into the gap between the
fender and the wheel well edge, then sealing the openings in the
highly curved area with SS heat treat foil stuck on with truck bed
liner. Then I sprayed 3M Cavity Wax on the repair and the opposite
side wheel well which didn't have the gap. Time will tell...

-jsw