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Properly installed and maintained asphalt should last for 25 to 30 years. An expected part of that maintenance is removing and replacing deteriorated material. Sometimes, you need to cut asphalt to install something in the ground below your driveway.
An angle grinder is one of the most powerful and versatile removal tools available. Whether you’re patching a pothole or installing an invisible fence wire, a powerful angle grinder will get the job done.
Steps for Cutting Asphalt With an Angle Grinder
Here are the steps for using your angle grinder to cut through asphalt and blacktop.
- Prepare your work area. Run an outdoor-rated extension cord from a GFCI outlet to the work site. Remove larger rocks and obstacles by hand. Finish by sweeping the asphalt to remove sand and dirt from the cutting area. Not only will this prevent the angle grinder from kicking up dust, it will also prevent unnecessary wear and tear on the blade.
- Mark your cut. A snappable chalk line is the easiest way to define the area to be removed. New asphalt will bond best with a clean, straight cut rather than a rough, rounded edge. If you’re filling a hole, give yourself a wide margin on each side. Three or four inches of clearance should be enough. Although this method removes more material, it’s less likely that you’ll have to repatch the same spot next year.
- Some people find it easier to follow the line of the cut if it has already been scored. You can score asphalt using a chisel and a hammer to dent the pavement along the chalk line. This step is optional, but recommended, especially if it’s your first time cutting asphalt.
- Put on protective equipment. Asphalt tends to break into chunks during the cutting process. If the blade catches one of these chunks, it quickly becomes a dangerous projectile. Using a full face shield is best practice to protect yourself from facial injury, along with a high quality dust mask.
- Prepare for using your angle grinder. Make sure the dust vent is clear. Attach a diamond blade with a strong bond that matches the size and RPMs of your angle grinder. Adjust the guard on the angle grinder so it is between your face and the blade. Guard removal is one of the leading causes of angle grinder injuries.
- Plug the angle grinder in, put both hands on the tool, and turn it on. Allow the disc to spin uninterrupted for a minute. There are a number of reasons an angle grinder disc might fail. Defective discs are common enough and dangerous enough that it’s worth your time to check new blades before using them. Letting the angle grinder get up to full speed will help it cut through the asphalt more efficiently.
- Plunge the spinning blade into the asphalt at a 90 degree angle. Do not tilt or twist the blade. Allow the tool to work at it’s own pace. Applying pressure or weight to the angle grinder makes kickback more likely, increasing the risk of injury.
- When the blade has passed through the asphalt into the dirt below, you should feel a change in resistance. Slowly move the angle grinder along the line of the cut. When you reach the end of your first straight cut, stop.
- Remove the blade from the asphalt and turn off the angle grinder. Inspect the cut. Jagged edges are a sign that you’re applying too much pressure while cutting. It could also be an indication that the bond of your diamond blade is too soft. If the cut is even and smooth, you can continue cutting.
- When all the marked lines have been cut, it’s time to remove the unwanted asphalt. Depending on how much asphalt you are removing, you may be able to do this by hand, or a shovel may be required. The asphalt may be in large pieces. If they are too heavy to safely lift, use a sledgehammer to break them up.
Angle Grinder Discs For Cutting Asphalt
To cut through asphalt, choose a diamond blade with a strong bond. The strength of the bond determines how easily the blade will release the diamond grit. We have a great article on how to change an angle grinder blade, if you need help.
Softer materials, like asphalt, require a stronger bond than harder materials such as concrete, marble or granite. A soft bonded blade used to cut asphalt will start releasing the diamond grit during the cut, wearing down the disc and resulting in a jagged cut.
To avoid having to cut asphalt, seal any cracks as soon as they appear and sealcoat the pavement every other year, preferably with a coal-tar asphalt sealcoat. This type of seal coat has unique asphalt rejuvenating capabilities and can actually improve the quality of your pavement.
Is an Angle Grinder the Best Tool for Cutting Asphalt?
The answer depends on how much asphalt you want to remove. An angle grinder is the perfect tool for making small, short cuts to asphalt.
Other scenarios where you might opt for a different tool:
- To completely clear an area of asphalt, a jackhammer would be the best option.
- If you need to cut a small trench to bury an invisible fence wire, a circular saw with a diamond blade or a worm blade saw would be a better choice. A 10″ – 12″ inch concrete cutting saw will cut through asphalt quickly, but will produce a lot of dust and be hard on the tool.
If you’re not sure how thick the asphalt is, dig at the edge of the pavement to see how deep it goes. For cuts deeper than 4″, rent a walk-behind circular saw.
While other tools may do the job more quickly or effectively, angle grinders are more than up to the task of cutting asphalt. If you already have an angle grinder in your DIY arsenal, there’s no reason to splurge on a new tool.
Angle grinders can safely be used to cut through asphalt less than four inches thick. A hard bond diamond blade is the best choice of angle grinder blade for cutting asphalt. Asphalt chunks make dangerous projectiles; take extreme care while cutting and always wear a full face shield. Thicker asphalt may not be suitable for removal with an angle grinder.