I have a buildt-in bookcase with a 1/2" ply back that [nearly] meets up with a wall that is slanted in at the top at 45 degrees. The back of the case and the wall are painted with the same flat wall paint. I want to put a cove at the junction of the plywood and drywall, probably with a 2-3" radius. That means that the material I build the cove out of will be up to 3/8" thick. I have both plaster of paris and drywall joint compound. Which should I use and why?
PS: A molding strip is out--I want to camouflage this intersection, not highlight it.
PPS: I guess that Lew is going to suggest epoxy with microbubbles. How hard would that be versus plaster or mud, and what would be the advantages?