Types of anchors and their uses...
All anchors can be divided into two basic types... expansion anchors and hollow wall anchors.
1) Expansion anchors are used in thick, solid materials... concrete, brick, mortar, metals or even wood. They work by expanding when a screw or bolt is threaded into them. If you remember anything about expansion anchors, remember this... Expansion anchors are only as strong as the material they are installed in. If an expansion anchor is installed in a soft material (such as drywall), it may appear to be strong but don't be fooled... the strength is minimal and it will eventually loosen and/or pull out if too much stress is put on it.
2) Hollow-wall anchors, on the other hand, will not work in solid materials. Instead, they are designed to be used in thin materials or on hollow walls. They each have a unique way of spreading within the hollow of the wall. Once spread, the anchor cannot be pulled back through the smaller installation hole. The strength of a spreading anchor is proportional to the size of the "spread"! Those are the basics... now lets look at some specific anchors from the least strong to the most strong.
Plastic (and other) expansion anchors
Plastic expansion anchors are one of the most commonly used... and abused... wall anchors. They are available in a number of sizes and designs (). Larger plastic anchors will accept larger screws and therefore have greater holding capacity. The more heavily "ribbed" anchors will give the greatest gripping strength, regardless of the wall material. When a screw is installed into a plastic anchor it expands, exerting force against the material it is installed in. As with all expansion anchors, they are strongest when used in a solid material, such as concrete. Their strength is even limited in concrete, though, because plastic is not indestructible... hence they may pull out because of anchor breakage! (For this specific application there are expansion anchors made of lead... above in the Installing a plastic anchor is a matter of first making a hole for the anchor in the surface. This can be done with a drill in hard materials, or an awl in drywall. I have always preferred using an awl in drywall since there is no dust produced. However, if you prefer using a drill choose an old, worn drill bit if you have one available. Drywall is very abrasive and will dull a good drill bit! Then just press the anchor into the hole until it is flush with the surface. It is preferable that the hole be slightly smaller than the maximum width of the anchor so, if necessary, tap the anchor flush with a hammer. Caution here... if the hole is too small the anchor will collapse when you tap it in! Overall, plastic expansion anchors are the least strong of all the anchors discussed here, with actual pull-out strength of around 30 pounds in concrete but as little as 10 lbs in drywall (depending on the anchor and screw size). Unfortunately, many people use plastic anchors in drywall when they shouldn't. When can you safely use a plastic anchor in drywall?
List of 3 items.
When the load is light and the force is perpendicular to the anchor. You can hang rather heavy pictures or mirrors using plastic anchors, placing the wire or picture hanging hooks onto the anchor's screw. Use two anchors and screws whenever possible... the additional strength is desirable plus doing this is good picture hanging practice, anyway. Ask any professional picture framer!! . To "steady" or stabilize a wall hanging that is being held up primarily by another, stronger anchor. This method of hanging is useful on towel bars or curtain rods that have two closely-spaced holes. Use a strong anchor such as a toggle in the top hole and a plastic anchor in the bottom hole. (More on this issue under "toggles"). . Never use a plastic expansion anchor in a ceiling under any circumstances unless you are hanging something extremely light, such as a smoke alarm! You will be sorry!
list end
Removing an expansion anchor...
If it didn't already pull itself out... insert a screw partially into the anchor and pull it out. Wiggling while pulling may help free up the anchor. THE SCREW, I mean! Threaded Drywall Anchors Known by the trade names such as "EZ-Ancor" or "Zip-It", this type of anchor is a basically a large, threaded nut with a point on the end! The large threads are intended to hold strongly into drywall and will accept #6 or #8 sheet metal screws. To install these anchors, it is advisable to first use an awl to punch a small hole the size of the "point" in the drywall. Though they are designed to be "self-starting", providing this starter hole will give you a more accurate installation. Then screw the anchor into the drywall with a Philip's head screwdriver until the head is flat against the wall surface. These can also be installed with a screw gun or a regular power drill with a screwdriver attachment. The surface of the drywall may distort, tear or slightly "buckle" as the anchor is installed... this is perfectly normal and to be expected. The pointed end of the metallic version spreads open in the wall when a long screw is installed. This spreading does not add any strength to the anchor... the points are just getting out of the way of the screw! In fact, the points can be broken off before installation if less penetration into the wall is desired. You would need to predrill a slightly larger hole for the large threads to grab the drywall, however. Threaded drywall anchors are available in both nylon and metal. In my opinion, forget about the nylon type. They are not very sturdy and are more likely to break when installed than the metal ones. The price difference is so slight that I don't understand why they are manufactured. I guess (choose one) either someone else likes them OR there is always a market for a cheaper product!
How strong are threaded anchors?
They have somewhat more holding strength in drywall than plastic expansion anchors... what doesn't... but not a lot more. Probably about double the strength... up to 15 lbs to 25 lbs on a good day. Over all, they are meant for the same, non-critical light-duty hangings as plastic expansion anchors, and shouldn't be relied on in critical applications.
Removing a threaded anchor...
Insert a screwdriver into the head of the anchor and turn counterclockwise until the anchor is free. The spreading "points" may enlarge the hole slightly as they emerge. Part of the game! Threaded Drywall Toggles These are the "big brother" to the threaded drywall anchor. They combine the threaded anchor's ease of installation with some of the strength of a toggle. To install, first screw the toggle into the wall. A toggle-like arm swings out perpendicular to the anchor as the screw is installed. Then, the toggle pulls towards the inside of the wall until flush to the wall. When installed properly they are quite strong... up to 40 lbs or more. That is, if they install properly! I have used these on four and only four occasions. On each occasion at least half of the anchors failed in one of two ways... either the "toggle" did not turn and engage the screw OR the screw strips the toggle. And I was forced... while gritting my teeth... to use a standard toggle to replace it. So... again only citing personal experience... I cannot recommend this type of toggle in its present design.
Removing threaded drywall toggles...
The toggle is not spring loaded, so removing the screw won't necessarily allow you to remove the toggle. When the screw is removed, the metal toggle might drop free. Then again, it might not. So you might not be able to remove this toggle. You have a few options... Use a screwdriver to turn the anchor counterclockwise to unscrew it from the wall. If the toggle prevents you from further removal, use a pair of snips or cutting pliers to cut the head off the body. Yuck! The body of the anchor will drop into the wall. You can then 1) repair the hole with lightweight spackle or drywall compound or 2) use a real toggle in the old hole to reinstall your hanging provided the wall isn't too damaged. If you can't cut the threaded drywall toggle apart, you can instead tap it into the wall by inserting a screwdriver into it and banging the end of the screwdriver with a hammer. Pound gently but firmly until the anchor is beneath the surface. If you continue to tap you will eventually push the anchor completely through the wall. If you are satisfied with a cosmetic repair and don't want to hang anything in the same location, tap the head slightly beneath the surface of the drywall and repair the hole with lightweight spackle or drywall compound.
Winged Plastic Anchors
This special type of plastic anchor is a compromise between strength and cost. They are much less expensive to manufacture than metal anchors, but offer more than double the strength of plastic expansion anchors. To install, first drill an appropriately-sized hole in the drywall. Then fold the wings towards each other and push the anchor through the wall. A special pointed tool is supplied with the anchor that is used to push the center of the wings out so that they properly expand in the wall. The anchor will not function properly unless this is done, even though it may feel strong when screwed into!! If you don't have the tool, a small screwdriver inserted into the screw hole will do the same job. Once the screw is installed, the wings are pulled firmly against the wall. Because these anchors are made entirely from plastic, they must be installed with some care. Too much force can rip the screws out of them or, even worse, collapse the wings. If they pull through the wall they will leave a large hole in their wake. Tightening the screws too much during installation or using too large a screw can also cause the threads to strip, making the anchor weaker. Given these drawbacks, though, they are still a decent choice for towel bars and other medium weight hangings. They should be able to support from 25 to 35 lbs each in drywall... adequate for most towel bars, toilet paper holders and other medium weight hangings. To my delight, some "enlightened" manufacturers are now beginning to supply this type of anchor with their towel bars and toilet paper holders. Hopefully more will follow suit!
Removing a winged-plastic anchor...
Turn a screw slightly into the head of the anchor and pull. It should come free. If it resists too much, you can use a 1/4" drill bit and drill the head off the anchor. The body of the anchor will drop into the wall.
Sleeve-Type Hollow Wall Anchors...
a.k.a. Molly Bolts Molly bolts are a mechanically interest anchor. They combine the ease of installation of a plastic expansion anchor with much greater strength. The largest mollys can hold up to 50 lbs. Essentially, a molly bolt adds permanent screw threads to any material it is attached to. Thus, anything installed with a molly can be installed and taken down a number of times with no loss of strength. This style is typically used to add support to hollow doors for hanging towel bars, coat hooks and even "dummy" doorknobs. The second and third mollys are called "drive mollys", the second designed for 1/2" thick drywall and the third for 5/8" thick drywall. They both have a combination metal/plastic point that supposedly allows them to be driven into drywall with a hammer. Don't count on it! More later... The lowest molly in the graphic is an original-style molly... sans point! Mollys come in sizes from 1/8" to 1/4" (that's the screw size). As with most anchors, use the largest size that will work for the task at hand since the larger the molly, the greater the strength! To install a molly, first drill a hole the diameter of the molly in the desired location. Predrilling is important even with "drive mollys" since they can be bent or distorted if the wall is too hard. For smaller mollys, an awl can be used to form the hole as described for installing plastic expansion anchors (above). Tap the molly into the hole until the head is flush with the drywall. Molly's have metal "teeth" that grip the drywall, and it is important these teeth are firmly embedded. Then turn the molly's screw clockwise. This pulls the base of the molly towards the inside of the wall while expanding the metal legs. A tip... though most molly screws have a combination Phillip's/slotted head, use a slotted screwdriver... the Phillips may slip and cause damage to the wall! Stop screwing when you feel strong resistance and the top of the molly has pulled tightly against the wall. There is a plier-like tool known as a molly setter that can be used to expand mollys without the use of a screwdriver. The tool pulls the screw head straight out, expanding the legs. This tool is a real timesaver for a pro, but is somewhat expensive for the weekend molly installer! Oh... the humanity! Removing a sleeve-type anchor... Mollys are very difficult to remove, since the expansion is permanent. IF you are not going to hang anything in the same location, place a screwdriver or nail set onto the head of the molly and tap in gently till it pushes beneath the surface of the wall. Then repair the wall with lightweight spackle or drywall compound. IF you want to reuse the hole (for a toggle, of course), you have still more options. You could try to tap the anchor through the wall. Then select a toggle bolt sized to easily span the now gaping hole. Or you could be daring and try to drill the molly out. Select a very sharp drill bit at least twice the size of the molly's screw. Drill directly into the screw hole, while pressing firmly so that the molly does not spin. With any luck, the head of the molly will break free and the body will fall into the wall. If your luck has run out, the molly might begin to spin in the wall. Then, your only option is to tap it through the wall and pray for deliverance!!
Toggle Bolts
Toggle bolts are the Cadillac (or Lexus, if you prefer) of hollow-wall anchors. They consist of two parts... the toggle itself (which looks like a pair of spring-loaded metal wings) and the accompanying machine screw. Toggle bolts are sized in two ways... by the diameter of the machine screw and by the length of the machine screw. The larger the screw diameter, the larger and stronger the toggle. The longer the screw, the thicker the material that can be hung or the thicker the wall it can be used in! Toggles are massively strong. A "puny" 1/8" toggle can safely hold 50 lbs on 1/2"
drywall...
a 3/8" toggle over 100 lbs! Two or three 3/8" toggles can easily hold up most kitchen cabinets on solid 1/2" drywall. That is, as long as the wall is strong enough! Toggles are the toggle of choice for hanging most anything from ceilings, too, such as hanging plants, mobiles, etc. The major exceptions would be "dynamic" objects such as ceiling fans, which require attachment to structural members. Also, though excessive weight may not break a large toggle through the ceiling, the ceiling itself may pull away from the joists! To install a toggle, first drill a hole in the desired location.
Here is a drill sizing chart...
Table with 2 columns and 7 rows
Toggle Size Drill Bit Needed
1/8" toggle 3/8" drill
3/16" toggle 1/2" drill
1/4" toggle 5/8" drill
5/16" toggle 7/8" drill
3/8" toggle 7/8 drill
1/2" toggle 1 1/4" drill
table end
Now it's time to assemble the toggle. Push the machine screw through the object to be fastened and attach the toggle to the screw. Thread the toggle far enough that the threads of the screw keep the toggle from turning sideways Otherwise the toggle may not open properly in the wall. Raise the object into position and push the toggle(s) through the predrilled hole(s) until you hear or feel the toggle snap open. Then pull back on the object or the screw to keep the wings from spinning while you tighten the screw. One problem with toggles is that they do not give you a precise location as do all the other anchors we have discussed. So once the toggle is almost tight, check the position of the object and then fully tighten the toggle. Don't overtighten the toggle in drywall or you might either break the toggle or break the wall!
Tricks with Toggles!!
) Some towel bars may have their screw holes very close to the edge. This can cause a problem with a toggle because of the large hole needed to install them. To make this situation workable, first position the towel bar and mark the holes. Then drill the appropriately sized hole "offset" so that the hole is fully concealed behind the towel bar BUT still allows the molly screw to be in the right location. Neat trick, huh? 2) As mentioned earlier, one problem with standard toggles is that they do not tighten to a precise location. Instead, you need to position them as they are tightened. This can be a pain! The solution is to use a toggle in one hole to supply strength and a plastic expansion anchor in the second hole to get the bar into the correct position.
Removing a toggle bolt...
Toggles are the easiest anchor to remove. Just remove the screw, which causes the toggle wing to drop into the wwall. Repair the wall or cover the hole with a picture. Done.