When I paint the interior of a house, I often end up with 30 or more doors that need painting. I’ve found the easiest way to do this task is to take all the doors out of their frames and move them into the largest room in the house or into the garage. There, I stack the doors atop one another and paint their tops and bottoms with a roller. Then I put down two rows of 1×2 strips and stand the doors up on them in long lines, as shown in the drawing.
The first door is set at 45° to the strips, and the next door is set at 90° to that so that they look like one long folding door. One person stands the doors up, and a second person connects them by nailing a 1×2 across the top. Once the doors are ganged together, I remove all the hardware and put the fittings for each door in a Ziploc bag coded to its door. With this method, I can paint all the doors at once, whether by spray, roll, or brush; allow them to dry; and reassemble them all in one spot.
Jon Tobey, Monroe, WA