First remove handles, keyhole plates, finger plates and coat hooks to give yourself an uninterrupted surface. If you try to paint round these they will cause a build-up of paint, leading to unsightly runs. Clean out the keyholes to remove dirt and grease, which otherwise will be picked up on the brush and transferred to the rest of the work. It is a good idea to paint the top of the door as well, because although it is not normally visible it will make cleaning that much easier. Open the door and fix it in position with a wedge underneath, leaving both hands free for painting. This will also ensure the door stays where it is until the paint has dried. Plan to finish painting each area in one session to avoid the edge line showing up where painting is restarted.
Panel doors
Preferably use a 50mm brush, although you can use a 25mm one to make it easier to cut into mouldings. Don’t overload the brush when painting the mouldings, as a build-up of paint will cause runs.
Flush doors
A 60mm or 75mm brush is best; if you prefer, a pad or suitable roller can be used. Any of these will enable you to complete the work quickly and join up all the edges before they start to dry. When painting hinges, clean out the newly painted screw slots with a screwdriver before the paint has started to dry. Wipe the blade immediately after use. Clearing the slots is essential as you may want to remove the door at a later stage or adjust the hinges.