When sealing I always try to blow into the can to remove all the oxygen I can which is replaced with my carbon monoxide. I use to do this with house paint and it really works. I figure it may help to keep the Por15 fresh.
The Por15 can says to also put a layer of saran wrap over the can before closing it AND its best to store it in the refrigerator. I didn't and mine, what little I have left, held up pretty good. Opened it and used it about 4 times over a 3 week period.
I don't know why it doesn't "dried uniform" but on my chassis the places where it looked a little different were where some rust had set in. It could be that its the way the light reflects on it?? If I look straight down on those area's it appears to be the same....and of coarse it may depend on how well its stirred?


1937 Chevy Pickup
In the Gallery
1952 Chevy Panel
In the Gallery
More photos
1950 Chevy Coupe
Pictures!

I'd rather walk and carry a Chevy hub cap than ride in a Ferd.
I can explain it to you, but I can't understand it for you smile