How to take out the expansion screw?

Expansion screws are generally referred to as metal expansion screws. The fixation of expansion screws is to use the wedge-shaped slope to promote expansion and generate frictional binding force to achieve a fixed effect. The screw has a thread on one end and a taper on the other end. There is an iron sheet (some are steel pipes) on the outside. Half of the iron sheet cylinder (steel pipe) has several cuts. Put them into the hole made in the wall together, and then lock the nut. The nut pulls the screw outward, and the taper is pulled into the iron sheet cylinder. , The iron cylinder is expanded, so it is tightly fixed on the wall, generally used to fasten protective fences, awnings, air conditioners, etc. on cement, bricks and other materials. But its fixation is not very reliable. If the load has a large vibration, it may loosen, so it is not recommended to install ceiling fans.

1. To remove the expansion screw, first remove the screw cap, then use a hammer to knock the screw into the wall, and then use pliers to pull out the iron sheet outside the screw. After pulling out the iron sheet, clamp the screw with pliers and pull it out while shaking. That's it; hit it up and down with a small hammer, shake it a few times, and you can easily take it out. Some are very strong and still can't be pulled out. Use a chisel to cut off points around and pull out while turning. If it doesn't come out, use a 6mm electric hammer drill bit to drill directly in, the depth is not less than the depth of the screw, and then use pliers to clamp the outer ring while turning it out, so that the most stubborn can be pulled out.

2. First, knock the exposed bolt part into the wall to separate the bolt expansion part from the outer expansion tube. Then use needle-nose pliers to clamp the expansion jacket and pull out forcefully. After pulling out the expansion jacket, push the screws in when pulling the expansion tube. The bolts can be easily taken out. If the knocking is not loose, you can only use a hammer drill to loosen the periphery of the sleeve, and then repair the wall.

3. Saw the outside with a hacksaw, and then drive it all into the wall. In the future, the expansion bolts will rust and squeeze the stucco layer of the wall.

4. Corrosion with sulfuric acid. However, this method is not safe and environmentally friendly, and has a greater impact on the wall. Not recommended!