Auxiliary jets, usually compressed air and sometimes liquid CO2, directed at the part beside or behind the gun to remove heat between passes. They hold substrate temperature within limits, reduce residual stress and keep thin or heat-sensitive parts from distorting or changing metallurgy. Air jets also sweep away loose overspray, but they must be clean and dry, since oil or water from the plant air contaminates the coating.
Turn the cooling air up on the thin wall, it's already at 300 after four passes.
Also heard as
- air jets
- air knives
- CO2 cooling
Related terms
Substrate temperature
The temperature of the part being coated, usually held below about 150 °C during spraying.
Residual stress
Stress locked into a coating and substrate after spraying, from splat shrinkage, cooling and impact.
Cook
Booth slang for overheating a part during spraying, usually from slow traverse, short standoff or no pauses.