Cleaning holes for adhesive anchors
Adhesive anchors fail at the bond line, and dust is what breaks the bond.
Why it matters
Bonded anchors transfer load through adhesive contact with the hole wall. Residual dust acts as a release agent and can reduce capacity dramatically.
Follow the manufacturer's cycle
Most systems specify a sequence of blowing and brushing, repeated a set number of times, with a brush of the correct diameter.
The cycle is part of the approval. Shortening it invalidates the published capacity.
What extraction does and does not do
Drilling with extraction removes much of the spoil as it is produced and leaves a cleaner hole.
It does not remove the fine adhered layer on the hole wall. Still brush and blow.
Wet holes
Water in the hole changes requirements. Many adhesives have separate instructions — or prohibitions — for damp or flooded holes.
Questions about this
Why do adhesive anchors need such thorough cleaning?
They transfer load through adhesive bond with the hole wall. Residual dust acts as a release agent and can reduce capacity dramatically.
Can I shorten the cleaning cycle if I drilled with extraction?
No. The cleaning cycle is part of the anchor's approval. Shortening it invalidates the published capacity even if the hole looks clean.