I need to construct a solid core door for the knee wall attic in our new room. Rather than purchasing a custom door, have people been successful in constructing a door from particleboard or MDF? I have a doorknob borer from Harbor Freight for just such a possibility. I'm thinking about cutting a 4'x8'x3/4" into two 2'x3' pieces and sandwiching two with liquid nails, then boring the knob and latch holes.
You won't get cheaper or easier than two layers of sheet lumber. Particle board is a common component in 30-minute fire doors (though they usually have a hardwood veneer).
I'd do just as you plan. Sand or route a bullnose all the way around and seal it with a couple coats of urethane, smoothing with steel wool between.