Foam Aquascaping?

[Black Phantom]

The thought of having the spray foam break down is not a good thing.
What about sculpting something out of high density foam, like the pink stuff from Home Depot, and then covering it with a two part epoxy paint.
Do you think this would hold up to a salt enviroment.
I've had some of the pink stuff under my sump for five years now and so far it hasn't been affected from the salt water or the salt creep.
Do you think that would work?