Wall plugs need brick, block or concrete to hold well. Plaster just will not do, because it has minimal holding power. It's normally way too soft you see. Sure, if the wall is plastered with tough cement render and thin skimming coats, you may get away with some light to medium loads, but typically the plastic plug needs to be pushed into the wall itself so it's whole length is into a brick, a block or concrete and so on Many individuals want to learn how to use wall plugs . Because the way a wall plug works and holds in location is by expanding in a radially outwards style. Simply put, when you put a screw into a plastic wall plug (or an old fashioned wooden plug for that matter) it serves as a wedge, pressing the 2 halves of the plug apart and filling the hole really tightly. Friction then takes care of waiting in place for all eternity; useful things friction ... and it's complimentary! Most wall plugs are only 1 1/4 ″ to 1 1/2 ″ (32 to 38mm) long and most plaster on wa...