Views: 228 Author: SEPPE Garnet Team Publish Time: 2026-08-05 Origin: SGA Blasting
A low-dust abrasive can make blasting easier to manage, but it cannot make the process dust-free. The cloud around the nozzle is influenced by what happens to the garnet on impact and by what the jet removes from the surface. These sources should be separated before a batch is judged.
Some dust enters the blast pot as fine material already present in the abrasive. Moisture can make those fines cling together and disturb the feed. When the material dries or breaks apart, the light fraction is carried into the air stream.
More dust is created at impact. Each grain strikes the work surface and loses part of its structure. Grains that fracture too readily produce fines sooner, while tougher grains tend to retain useful cutting action for longer. Hardness still matters, but a harder abrasive is not automatically the lower-dust choice.
The work surface also contributes. Old coatings break apart during removal. Rust and mill scale fragment as well. On maintenance jobs, these materials may account for much of the visible dust, so the dust cloud alone is not a reliable test of garnet purity.
Poor visibility makes it harder to hold the nozzle at a consistent distance and see whether the surface is cleaning evenly. After blasting, settled material adds to housekeeping and can delay inspection. The effect becomes more noticeable in enclosed or poorly ventilated work areas.
Low dust can improve working conditions, but it does not prove that the steel is ready for coating. Surface cleanliness, profile and soluble contamination must still be assessed against the project specification. Ventilation, dust collection and personal protection also need to follow the site risk assessment.
A blasting grade should arrive dry, free-flowing and within its agreed particle-size distribution. Excessive fines add little useful impact energy and enter the air stream easily. An unstable distribution can also change abrasive flow and make the resulting surface less predictable.
Colour is not a dependable shortcut. Natural garnet varies with its mineral source, and a redder product is not automatically cleaner or tougher. Compare sieve data and moisture information first, then confirm performance with a controlled blast trial.
Start with the air supply. Condensation entering the blast pot can make fine material cling together and interrupt metering. Drain collected moisture and confirm that the abrasive remains dry before treating the batch as the cause.
Set the abrasive flow gradually while working on a small test area. Too little feed weakens the cleaning action. Opening the metering valve too far can flood the air stream and raise consumption without producing the same gain in output. Once delivery is even, record the valve position for that setup.
A change in the blast pattern may come from nozzle wear rather than the garnet. Inspect the nozzle before compensating with more abrasive. If delivery still fluctuates, follow the hose path and look for a restriction or leaking connection.
Finish with a controlled trial on a familiar surface. Keep the nozzle technique and pass speed unchanged. Compare the resulting cleanliness and profile, then record actual abrasive use. This provides a more useful comparison than judging the dust cloud by sight alone.
When dust rises unexpectedly, compare the new lot with an approved sample while the equipment is inspected. Wet air or a worn nozzle can resemble an abrasive problem. If the machine condition is unchanged but the fine fraction has increased, isolate the lot and review its batch information.
Further reading: SGA Garnet Quality Control: From Raw Material to Loading
For grade information or batch documents, contact SEPPE with the blasting application and the specification used for acceptance.
