Always fit door stops to prevent doorknobs from chipping paint or even punching holes through plasterboard walls. Two types are available -- fixed post and hinge-mounted. Hinge door stops work best on light hollow-core doors and are available in a variety of colours and materials. Fixed-post door stops are screwed on to the skirting board and are designed for heavier doors; they will outlast the hinge pin variety. Either type can be fitted in less than five minutes.
Push a thin wooden wedge under the opening corner of the door to prop it open. Ask someone to hold the door steady while you fit the door stop.
Remove the upper hinge pin by holding a thin pin punch against the bottom of the hinge pin from below and tapping it free with a hammer.
Slide the hinge pin through the hole in the door stop so that the threaded adjustable nylon buffer faces the wall and the fixed buffer rests against the side of the door.
Replace the hinge pin with the attached door stop and tap the top of the pin all the way down with a hammer.
Screw the threaded hinge pin buffer in or out to adjust the door stop.
Lock the adjustable nylon buffer by putting a single drop of acrylic glue on the machined thread where it enters the hinge pin buffer body.
Don't force the wood wedge in under the end of the door with a hammer; it is only meant to support the weight of the door while you work.
Put a drop of oil on the hinge pin before you replace it.