Question 1

What is abrasive blasting?

Accepted Answer

Abrasive blasting propels an abrasive medium at high velocity to strip rust, mill scale, old coatings and contaminants from steel, concrete and masonry. It leaves a clean surface with a measured profile that new coatings can grip, which is the single biggest factor in how long a protective coating system lasts.

Question 2

What do Sa 2½ and Sa 3 mean?

Accepted Answer

They are visual cleanliness grades for blast-cleaned steel under AS 1627.4. Sa 2½ is very thorough blast cleaning with only slight staining remaining, and is the usual grade for most protective coating systems. Sa 3 is blast cleaning to visually clean steel, specified for demanding systems such as some zinc-rich primers.

Question 3

Can you sandblast on site?

Accepted Answer

Yes. We blast on site at bridges, industrial plants, commercial buildings and heritage structures, using containment, dust controls and air monitoring to protect workers, neighbours and the environment. Wet blasting and alternative abrasives are available where dust must be kept down, and spent abrasive is collected and disposed of correctly.

Question 4

How soon must blasted steel be coated?

Accepted Answer

Freshly blasted steel starts to rust quickly, particularly in humid conditions, so a primer is normally applied the same day. We check surface cleanliness, profile, dew point and steel temperature before coating, and record the results, so the primer goes onto a surface that meets the coating manufacturer's requirements.