How to Remove Corroded Metal Screws
When brute force isn't enough to remove a rusted screw using just a screwdriver, try one of a number of other strategies .
One of the main problems you encounter when trying to remove rusty or corroded screws from decking boards or anywhere else is that the slots no longer hold a screwdriver. You can get around this by using pliers or a screw extractor, but if the screw is severely rusted, the head may break off. The procedures for extracting rusted screws range from mildly troublesome to drastic, depending on how difficult the screw is to remove. Start by removing paint and varnish from the screw slots with an awl.
Basic Extraction Strategies
Things You Will Need
- Rubber band or rubber glove
- Locking pliers
- Epoxy glue
Using the proper screwdriver for the screw head, bear down with all your weight before trying to turn it counterclockwise. It helps to use the longest screwdriver you have -- the longer the handle, the more of the force you apply to it gets transferred to the screw.
As soon as the head starts to strip, stop applying torque. Remove the screwdriver and put a thin piece of rubber, such as a rubber band or rubber glove, between the head and the screwdriver. Try again.
A drill can apply more torque than you can by hand. Push the drill, fitted with the appropriate screw bit, onto the rubber with as much force as you can muster and operate the drill for a second in reverse.
Chip out enough wood around the screw head -- using a chisel -- to allow you to grip the head with locking pliers. Once the pliers have a firm grip, use them to turn the screw counterclockwise.
If you don't want to chip out wood -- or the screw is embedded in metal -- find a nut that's the same size as the screw head or a little bigger and glue it to the head with epoxy cement. When the glue sets, use a wrench to turn the nut and extract the screw.
Start with a screwdriver.
Get your drill.
Glue a nut.
The Screw Extractor Option
In some cases, a special drill bit called a screw extractor is your best bet.
Things You Will Need
- 1/8- to 1/4-inch drill bit
- Screw extractor
Drill a 1/8- to 1/4-inch hole in the screw head, using a metal boring bit. Make the hole about 1/4 inch deep. Wear goggles when drilling into metal because tiny shards can easily fly into your eyes.
Fit a screw extractor to your drill. Use one of an appropriate size for the screw.
Push the tip of the extractor into the hole, put your full weight on the drill, and run it in reverse. The screw should back out.
Oops ... the Head Broke Off
It's common for rusty screws to break when you try to extract them. When this happens, you have two options. One is to fill the hole and forget about it. The other is to remove all the other screws holding the pieces together, separate the pieces and extract the shank of the broken screw by turning it with pliers. If you prefer, you can cut the shank with a hacksaw or bend it back and forth with pliers until it breaks.
Chris Deziel has a bachelor's degree in physics and a master's degree in humanities. Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since 1975. As a landscape builder, he helped establish two gardening companies.