Let's back up - pine, wainscoting - already up, rec-room.
Some questions need answers before the initial question can be answered with any specifics.
Since wainscoting is on the wall, not the floor, what is the concern about durability? Walls don't get a lot of contact in use. And, unless someone sprays drinks, say soft drink or booze, not much is going to get on the wainscotting other than what's in the air over extended periods of time (smoke - from cigarettes, cigars, fireplace, candles, ...).
Is the rec-room in a basement, partially or totally below ground level - or - above ground with no exterior walls?
Was the wainscoting applied over sheet rock/dry wall?
If a wall is an exterior wall, is there a vapor barrier and insulation behind the wall?
Will there be furniture up against the wainscotting and if so, upholstered or wood making possible contact with the wainscoting?
Will there be kids leaning against the wall with their foot/ shoe on it? Will little kids be crashing toys into the wainscoting?
Is the wainscoting going to get a lot of direct exposure to sunlight?
Now to some general issues/points about shellac.
- The solvent is alcohol - which ain't good to breathe - and is flammable. Is there plenty of ventillation for the rec-room? Is there any source of open flame, or anything that might spark in that space? Durability stops once a fire starts - and an explosion makes it a mute point as well. Hot or BOOM is more of a concern if you intend to spray on the finish.
- Most of the "problems" with shellac are with the wax that's in "normal" shellac, not the shellac itself. So de-waxed shellac is far less prone to White Rings or Blushing (white hazy areas in the finish).
- Shellac, dewaxed or not, is a Hot Finish - each new application "melts" the top of the previous application, forming a continuous film - unlike a Cold Finish which relies on a mechanical bond between LAYERS (with Cold Finishes you must sand or steel wool between coats to get the LAYERS to adhere to each other). With Cold Finishes repairs require "feathering" to disquise "witness rings" (think "grain pattern" when sanding through growth rings on a board). So to disguise a repair to a 6" long scratch in the finish, you may have to "feather" sand 3 or four inches all the way around the scratch. With shellac you may not have to sand at all - wipe on more shellac and be done with the repair.
- Shellac, once cured, doesn't outgas. Most Cold Finishes do.
- Shellac dries FAST - especially when "padded" on in thin coats. How much dust is in the air in the rec room? Dust nibs will show - a little or a lot depending. The slower the finish is to dry the more dust nibs to deal with.
- There is a dewaxed shellac usually called Platina that's almost "white" - very little yellow at all. Expensive but if you want as little color change as possible, it has all of the pluses of shellac.
charlie b