Doc wrote:
"RicodJour" wrote in message

The hinges will be fine for a door of that weight and size as long as
they're mortised into both the door and frame.

Check.

Why do you want to use drywall for the door? I realize that you're
looking for sound deadening properties, but I don't know about the
durability of drywall on a door.

Exactly that, sound deadening properties to match the rest of the booth.
This will be basically a "room within a room". If all goes as planned, the
drywall shouldn't be taking any of the structural stress of the door. The
plan is to make the frame very rigid and for the drywall to act strictly as
a sound barrier along with the insulation laid inside.

What are you going to use for the
latchset?

To keep the door closed I'll use flush-mounted magnets and strips of sheet
steel, which will be epoxied into an exposed area on the inside of the door
frame and a stop edge mounted on the inside frame of the booth. Figured I'd
use a router to cut the slots for both items, or maybe a boring bit if I use
round magnets. All I need it to do is keep the door shut, no need for it to
lock. I want to be able to push/pull it open easily when entering/exiting.

Your design is going to be more of a problem than I think you realize.
There are all sorts of problems with it:
- door swing clearance on a 4.5" thick door. What sort of gap is
required and how does that affect the sound transmission?
- regardless of what 2x4s you use, they're not furniture woods, and
always have a bit of twist or warping in them. At almost 4' wide even
a little twist will leave a gap, and even a little gap lets through a
_lot_ of sound. My acoustics professor would tell us that acoustically
speaking an 1/8" gap at a door is essentially the same as leaving the
door open.
- the more I think about it, the less confident I am about my earlier
advice about the hinges with a door that size. It's the width of the
door that is the biggest factor, not the weight. I think I'd go with
two pair of hinges to be on the safe side.
- drywall on a door is not a good idea. The surface is not hard enough
to stand up to the abuse a door takes. If you want to tiptoe through
the door every time you use it, it might be okay, but people push doors
open with their hips when their hands are full and the facing paper
will tear. I don't think it will be too long before the door looks old
before it's time.

I'm not sure how critical your soundproofing requirements are, but a
standard arrangement is to have two doors with one hung on either side
of the wall. The separation is at least as important as the doors
themselves.

Why don't you tell us what the application is and what the room will be
used for? The door is an oddball size, as is your intended
construction. Maybe we are looking at this the wrong way.

R