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?
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

Markem wrote:

On Thu, 22 Mar 2007 20:58:29 -0400, alexy wrote:

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?

Neither a flexible paintable caulk, it will not crack as joint
compound or plaster will.

How would I get a good surface on that? This "fairing" will be a
little over 2" wide if I go with a 3" radius. That's a LOT of caulk.
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

On Thu, 22 Mar 2007 20:58:29 -0400, alexy wrote:

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?

Neither a flexible paintable caulk, it will not crack as joint
compound or plaster will.

Mark
http://home.mchsi.com/~xphome/

On Thu, 22 Mar 2007 21:23:53 -0400, alexy wrote:

Markem wrote:

On Thu, 22 Mar 2007 20:58:29 -0400, alexy wrote:

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?

Neither a flexible paintable caulk, it will not crack as joint
compound or plaster will.

How would I get a good surface on that? This "fairing" will be a
little over 2" wide if I go with a 3" radius. That's a LOT of caulk.

A wood cove moulding, caulk to fill a small gap at the wall? If you
want a plaster cove attach it to the wall but not the bookcase, caulk
the joint at the bookcase. How you make plaster cove, I've seen it
done but am not going to attempt it.

Mark

alexy wrote:
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?

Use both. Do the first coat with the plaster of paris (which is
basically what setting type joint compound is)over fiberglass tape and
then use the premixed joint compound for the finish coat(s).

Why? Plaster will shrink less and dry harder. Joint compound shrinks
more, but sands easier.

On Thu, 22 Mar 2007 20:58:29 -0400, alexy wrote:

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?


Plaster or joint compound will crack. Bookcases have a tendency to
move around a little. I'd use a wooden cove painted the same color
with paintable caulk. The caulk can flex a small amount which is what
you want.