Clean the Hole Before Installing Asphalt Anchors
Hole cleaning is one of the most important steps in an Asphalt Anchor installation. Dust, loose asphalt, and drilling debris prevent the adhesive from bonding fully to the wall of the hole. Skipping or rushing this step can reduce pull strength by more than 25%.
The basic sequence is:
- Brush the hole.
- Blow out the debris with compressed air, a blower, or similar.
- Brush the hole again.
- Blow it out again.
Then install the adhesive and anchor using the standard installation guide.
Use the Right Brush
Section titled “Use the Right Brush”Use a hole cleaning brush that reaches all the way to the bottom of the drilled hole. We sell a hole cleaning brush, but any brush is acceptable if it fits the hole and reaches full depth.
For best results, the brush should be about 1 mm larger than the hole diameter. This helps the bristles press lightly against the sides of the hole instead of passing through the center without cleaning the wall.
Smaller brushes or older brushes can still be used if they are in good shape. Make sure there is light pressure on the hole wall, and circle the brush around as you move it up and down.
Drill Setup
Section titled “Drill Setup”Use the brush with a locking drill bit extension so the brush reaches the bottom of the hole. Any drill can be used for this cleaning step.
Set the drill to:
- Normal forward rotation, not reverse
- Low speed, usually speed 1
Do not run the drill in reverse. Running the brush backward can break it.
Cleaning Process
Section titled “Cleaning Process”- Insert the brush to the bottom of the hole.
- Run the drill forward at low speed while moving the brush up and down.
- Pull the brush out and tap or clear dust from it.
- Blow the hole out with compressed air, a blower, or similar.
- Brush the hole again, reaching the bottom and cleaning the full side wall.
- Blow the hole out again until loose debris is removed.
The hole should be clean enough that adhesive contacts the asphalt wall directly, not a layer of dust.
Brush Wear
Section titled “Brush Wear”Hole cleaning brushes are consumables. They deform and lose cleaning pressure over time.
For best results, use a new brush after roughly 6-12 holes. If you keep using a brush longer, inspect it often and replace it once the bristles no longer press lightly against the sides of the hole.