Dealing with moisture in surface prep
Moisture is the number one problem with flowing abrasives with air. Damp abrasives don't flow well in dry systems. Moisture in the atmosphere causes problems in lines, tanks and valves.
Compressing air requires a huge amount of energy to generate a by-product of this is heat and water; therefore, to maintain dry grit, compressed air must be put through an air dryer before it reaches the pot.
Moisture-laden compressed air clogs blast pots with damp abrasives, damaging control valves and slowing down blast speeds. Moisture traps work well when they are new, but the fine filters in them become clogged with dust, oil and foreign matter very quickly. Blockages cause immediate pressure drop in the system. For example, 100 psi coming in from the air compressor passes through a moisture trap, leaving pressure out commonly 10% less (90 psi in this case).
High atmospheric humidity is outside the control of moisture traps, so dehumidifiers may be brought in as well. Moreover, moisture is a problem in even seemingly dry condition, which is why dry blasting operations use additional equipment such as aftercooler moisture separators to remove moisture from compressed/pressurized air to help mitigate loss in productivity and damage to equipment.
So, how do you eliminate the moisture problem?
Ignore it. Seriously. Just switch to a system that doesn’t care about moisture.
Wet abrasive surface preparation (WASP) machines are not affected by atmospheric pressure, or moisture in grit. They are designed to work WITH water, not fight against it. Keep your air compressor clean & you’ve got it made.
What about flash rust? WASP enables simultaneous application of anti-rust treatments while cleaning or during final rinse (using the same unit) to get rid of any residual grit on surfaces. Follow up (still using the same unit) to dry the surface, if needed. Flash rust prevented. No dehumidification needed.