Views: 166 Author: SEPPE Garnet Team Publish Time: 2026-08-03 Origin: SGA Blasting
When abrasive disappears at the nozzle, it is tempting to blame the garnet. Start at the blast pot instead. If the material leaves the pot normally, move downstream until the point of interruption becomes clear. Damp abrasive may be responsible, but the fault can also lie in the air supply or feed equipment.
Stop and isolate the equipment first
Shut the system down before opening the pot or separating any part of the abrasive line. Follow the manufacturer’s isolation procedure and confirm that stored pressure has been released. Only authorized personnel should perform this work under the site’s lockout/tagout procedure.
“Not producing sand” is not a precise fault description. First establish whether the flow has stopped, weakened or begun to pulse. That observation determines where the inspection should begin.
| Observed symptom | What it suggests | Where to begin |
|---|---|---|
| No abrasive output | The pot may not be feeding, or the line may be completely blocked. | Verify the abrasive level and pressurization. Then check the metering valve. |
| Pulsing or intermittent flow | Something is interrupting delivery without stopping it completely. | Look for damp abrasive first. If it is dry, examine the air supply and valve movement. |
| Reduced but steady flow | The metering setting may be low, or a partial restriction is limiting delivery. | Compare the valve position with the approved setup before making an adjustment. |
| Blockage after changing lots | The condition of that shipment or its grading may be involved. | Set the affected material aside and compare it with an approved sample. |
Do not open several valves in the hope that the blockage will clear. Directing high-pressure air through a disconnected line is also unsafe. Use the clearing method specified for that blast machine.
Moisture binds individual grains into lumps that the metering system cannot pass reliably. The warning signs often appear before the bag is opened: torn packaging, a wet pallet or marks left by rain. Set visibly damp material aside. Returning it to the pot usually repeats the problem.
A blasting grade covers a controlled range of particle sizes; it does not make every grain identical. One unusual grain therefore proves little. A sieve result is more useful. It can show whether oversize material is present, while a retained sample helps reveal a change between lots. Foreign debris is a separate issue and may block a narrow passage on its own.
Particle appearance can reveal foreign material or visible clumps, but sieve and batch data are needed to evaluate grading.
Correct grading cannot compensate for poor storage. Keep unopened bags clear of wet ground and close partly used packaging before humidity reaches the abrasive. On arrival, inspect the container before unloading and record any damaged bags. SEPPE’s available formats are shown in Garnet Abrasive Packaging: 25 kg Bags and 1 MT Jumbo Bags.
Bulk packaging and container condition should protect garnet from moisture before it reaches the blast pot.
Suppose the sample is dry and its grading is within specification, yet the flow still pulses. Watch the air supply. Condensate reaching the pot can wet the abrasive during operation. If the air remains stable, return the metering valve to its approved position and test again. A continuing fault then points farther along the isolated line, where a kinked hose or physical obstruction may be visible.
After maintenance, reassemble the system and complete the required safety check before restoring energy. Return the valve and pressure to their approved settings. A short controlled test will show whether steady flow has returned. If an adjustment is needed, change one setting and observe the result before touching another.
A known dry sample is useful at this stage. When the fault remains with that material, continue investigating the equipment and air supply. When it appears only with one lot on a verified system, retain a sample and review the batch information with the supplier. This simple comparison keeps an equipment fault separate from a genuine material problem.
