HIDDEN COSTS OF WORN BLAST NOZZLES
Another form of the More is always better myth reveals itself with blasters preferring worn out blast nozzles over new nozzles. Their reasoning is thus, “The worn out nozzle provides a larger blast pattern. A larger pattern means I’m able to clean the substrate faster.”
Using only visual calculations, that would seem correct. But there are many unseen variables involved with blasting that the operator isn’t taking into consideration and are quite costly.
- The first is that a wider orifice through the nozzle – due to wear and erosion of the inner venturi – creates
- Overall pressure loss
- A decrease in the speed of the abrasive particles coming from the nozzle by up to 235 mph (slower)
- Halving productivity
- The second is the costly waste of abrasive. Any increase in orifice size will increase the air flow traveling through the nozzle – which will carry with it, more abrasive from the blast pot. This would also seem like a good thing – but as the previous Primed Insight revealed there is level of diminishing returns with abrasive flow, that simply wastes the abrasive – driving down efficiency, and increasing both abrasive and clean-up costs.
- A worn nozzle also will increase the amount of thrust the operator experiences – which is like friction against his stamina. More thrust tires out operators faster. And a worn nozzle can produce up to 30% more thrust.
The take away is simple: Worn nozzles lower blasting pressure, deplete an operator’s stamina and endurance over the typical workday shift, and waste costly abrasive… which then adds to clean-up costs. Never ever blast with worn out nozzles.