Doors purchased at a home center will provide a very insufficient frame to
build a
stage doorway out of. The lumber is normally slimmed down in
thickness and often dry enough it will split when not used as designed. Much less it’s stapled together only sufficiently so as to hold it together. This given once it's own shipping framing supports are removed, there is little to nothing left to the frame that won't fall apart and come out of square. Such a store bought frame depends upon later attachment to a structure to provide support - the pre-hung frame is only
molding with a door attached to it. Much less a pre-hung solid core door as
in one form or another will be necessary if the actors run into it. Such a door will cost an arm and a
leg pre-hung or not.
Not sure if I completely agree with the statements about advantages or disadvantages with soft verses hard flats. While hard flats can be at times easier to construct, when the show calls for a soft
flat by way of design intent, or when that’s what you have available, that’s what you use.
Painting also takes technique, no material without expert painting will look like wood from the back row of the audience short of stuff that is painted to look like wood - no matter the surface to be painted. Can’t simply stain and
varnish wood at all times if you want to see graining technique from afar. Much less short of a large budget, making period pieces look correct will require a lot of very expensive lumber. Not just lumber but
clear pine if not as otherwise necessary hardwood.
Attaching the door to the flats wood or canvass can be a question in this case. The door since you cannot attach to the floor certainly won’t
gain any more strength from it, much less the walls might shake more than necessary if not even come down. Support of the flats will be a must but they can be supported separately.
Given this door needs to be removed, I might suggest that you hit the library for some scenery for the theater text books and look for both
stage braces and
stage jacks, much less the typical door frame and doors used on
stage. Given such wishes have been done before, such concepts are already laid out.
Above a box frame door and doorway
flat, you might wish to do three hinges instead of two and make sure they are rugged both in installation and stature. Should you attach to another
flat in using the soft
flat method, various forms of lash lines and whalers still have strength advantages in picking up
shock loading over stuff that’s nailed or screwed. You need someone on site with experience in such things to help you because not even a
book will fill in all the details.
Beyond this, you probably would want some form of dual
stage jack on each side of the doorway frame. The
stage jack for this application typically will be designed so as to hold sand bags or
stage weights within it’s supports. This adds the weight
stage hands in helping can’t otherwise sufficiently support adequately. On the bottom of the
stage jacks, rubber coating the bottom of the
stage brace often once weighted will be sufficient to prevent the
stage jack from moving. Given this needs to be hit by an actor, perhaps attaching both
stage jacks together by way of plywood on the floor attaching them together when it has a rubber mat attached to it than would provide more structure. Given it must be struck, drywall screwing a
stage jack assembly to the door
flat frame should be sufficient to transport it afterwards. The
stage jack can typically go up in height 2/3 it’s distance away from the
flat. Some instances require a 45 degree angle otherwise for more support of force applied to the door or wall in transmitting that to the floor. Since some of this force won’t be supported by the
stage jack, extra support by way of
stage brace or a similar brace extending out further than the
jack or if as needed attached to the
floor plate of the
jack will help support the top of the door frame or even door frame
flat as one
unit.
Unscrew the
jack from the door, unhook the brace from the
flat, detach the whalers and lash
line cleat rope, remove the weights and the supports for the door are gone - no tools involved. While the new techniques have advantages, sometimes the old techniques in having been worked out over a hundred years or more will work.
Better than attaching a
stage brace to support the top, would be to somehow attach the doorway to some form of supports above. At very least some form of ensuring the
flat/door won’t fall over is necessary if at all possible. Otherwise, distance away from floor and weight equals support even when people
bounce off it.
For the door itself, potentially a door can be made simply out of a piece of ½" plywood with supporting frame for it in making it into a paneled door. The panel door frame is very strong. Given manufacture of the door, the frame can be skinned with plywood or plywood can be sandwiched by frame where necessary for support. I would recommend having a look at least at a door company website in how doors are constructed, than as with the above, consult
stage books on how to construct a door. You than have how it’s built in understanding and how as similar it’s built for the
stage both economically and stronger.