Of all steps in the process there are many possibilities when it comes to drying, depending on the investment you are prepared to make.  
 
The progression of possibilities for drying are as follows:

   1/ Air Dry
   2/ Fans at Room Temperature.
   3/ Space Heaters to Increase Temperature
   4/ Space Heaters and Fans.
   5/ IR Lamps
   6/ Conveyorized drying using IR and
       Convection (blowing hot air)

1 and 2 imply the curing time will be a function of the ambient conditions, i.e higher humidity means longer curing. Going to steps 3 and 4 will improve drying times significantly since the capacity of the air to absorb moisture increases significantly with temperature. 1-4 always happen outside the spray booth itself, potentially subjecting the sprayed components to dust. Step 4 represents a relatively low investment (components available from Home Depot) and will assure overnight curing in all weather conditions. This approach to drying will need to include a space relatively dust free, i.e. an insulated room close to or attached to the spray booth is ideal.

The introduction of IR represents an incremental investment, however when placed inside the spray booth itself, the 6 minute exposure time will produce the best finishes possible.
In this context, while one item is being exposed to the IR, the next item is being sprayed.
Additional curing is still required even when IR is used since any areas not exposed to IR rays will need additional curing.

The area used for this can be the prep area, or fabrication plant itself since susceptibility to dust is no longer an issue. Energy consumption for IR is lower than for the space heated approach.

The objective of the drying equipment is to dry the product enough to process it further, not necessarily to reach 100% cure, which can take as much as an additional week.

The best way to access curing is through either a scratch or cross hatch adhesion test.

For more on IR systems...

> www.infratech-usa.com
   (see Portable Curing)