A moisture trap is a filter fitted in the air line between the compressor and airbrush that removes water vapor and condensation from the compressed air. As air is compressed, moisture in it condenses into droplets. Without a trap, this water reaches the airbrush and contaminates the paint — causing sputtering, fish-eye effects, and inconsistent spray.
Types:
- Bowl-type moisture trap: A small canister with a filter element. Water collects in the bowl and is drained periodically. Most common for airbrush setups.
- Desiccant filter: Uses silica gel or similar desiccant to absorb moisture. More thorough but requires desiccant replacement.
Most quality airbrush compressors include a basic moisture trap. In humid climates or for critical work, an additional inline trap is recommended.
Maintenance: Drain the moisture trap regularly — when painting in humid conditions, you may need to drain it mid-session.
Related: Compressor · Regulator · MAC Valve