Plastic Expansion Anchors
A plastic expansion anchor is so named because of the plastic sleeve that's inserted into the wall prior to the screw being screwed into place. A pilot hole is drilled into the wall and the plastic sleeve is inserted. The appropriate-sized screw is then screwed into the plastic sleeve, which causes the sleeve to expand behind the wall, making it more difficult for the sleeve to come out of the wall. The decorative object is then hung on the screw. These anchors come in a variety of sizes to accommodate various weights. Plastic expansion anchors are the least secure form of wall anchor and should be used to hang things where the pressure on the anchor is perpendicular to the wall.
Threaded Drywall Anchors
A threaded drywall anchor is a screw or nut with a fin at the bottom of it. It may be either nylon or metal; the metal is a higher-quality anchor. When inserted into the drywall, the fin opens up, preventing the screw from coming back out of the opening created when it was installed. A small hole must be punched in the wall at the point of insertion, using a small nail or an awl, before inserting a threaded drywall anchor. The threaded drywall anchor is slightly stronger than a plastic expansion anchor.
Threaded Drywall Toggles
The threaded toggle anchor resembles the threaded drywall anchor, except the fin is in the center of the anchor. The cap is inserted with the toggle in the center and then the screw or nut is screwed in. As the screw is tightened, it pulls the fins until they settle against the interior of the drywall. When the screw is removed, often the toggle falls behind the wall so it can't be used again.The threaded drywall toggle is stronger than the threaded drywall anchor.
Winged Plastic Anchors
The winged plastic anchor is an anchor with two plastic wings at the end. It comes in a package with a small tool designed to open the wings once the anchor is inserted into the wall, holding the anchor in place. If the packaging does not include the tool, a small screwdriver can do the same thing. Stronger than the threaded drywall toggle, the winged plastic anchor suffices for typical household hanging requirements.
Molly bolts are bolts that have a metal sleeve around them and a pointed end. The molly bolt is installed by gently tapping the pointed end until it's in the drywall and then screwing the bolt into the wall. As the screw is tightened, the metal sleeve expands, creating an X shape behind the wall, which holds the bolt in place. Molly bolts are widely used for hanging relatively heavy objects such as art and shelves on drywall.
Toggle bolts are long screws or bolts with toggles at the end of them. The toggle is threaded partially up the length of the bolt, then held flat against the bolt and inserted into the drywall. As the bolt is tightened, the toggle tightens against the inside of the drywall. The toggle bolt is the most sturdy choice for hanging an object on drywall, regardless of what the object is.