694 Section 5 Refinishing Copyright Goodheart-Willcox Co., Inc. Spray Booth Type A good rule of thumb is to spray with, not against, the direction of airflow in the spray booth. In this way, the painter is not fighting the air movement. By spraying with the airflow, overspray will be drawn away from wet paint, rather than pushed into the wet paint. In a cross-draft booth, if the airflow is from the front of the vehicle to the rear of the vehicle, spray the vehicle in the direction of the airflow, front to back. In a down-draft booth, spray the vehicle from top to bottom. Figure 28-36 shows the spray sequence in a cross- draft booth. Figure 28-37 shows the sequence in a down-draft booth. Both of these are for complete paint jobs, where the entire vehicle is refinished. This is not a common practice in most body shops. Usually, only part of a vehicle is repainted. Air Hose There will always be at least one air hose in use when spraying a vehicle. If the painter wears a supplied air respirator, there may be two air hoses to contend with. Air hoses present at least two problems. First, when lying on the floor, the air hose may get in the painter’s way. A misplaced air hose can cause the painter to trip or stumble. These problems can be prevented if the painter handles the hoses as shown in Figure 28-38. Second, the air hose may touch the wet paint. If the hose is covered with dirt, the dirt will be transferred to the paint. Even if the hose is clean, it will mar wet paint. See Figure 28-39. To prevent this problem, keep the hose away from the vehicle. The painter should always know where the air hose is. Dupont Figure 28-37. This is the sequence to follow for a complete paint in a down-draft booth. Driver side Passenger side Start Finish Dupont Figure 28-36. This is the sequence to follow for a complete paint in a cross-draft booth. Driver side Passenger side 1. Start Finish 2. Start Goodheart-Willcox Publisher Figure 28-38. This painter controls the air hose by keeping it behind the back and out of the way. Front Rear Front Rear Exhaust Exhaust Air intake