Removal of the coupons from the solution – The coupons shall be immediately removed from the tank upon completion of the phosphating cycle. Coupons shall be sufficiently rinsed with clean water immediately upon removal from solution in order to halt the reaction. The coupon shall be rinsed for a minimum of 30 seconds. The coupons shall then be completely dried using compressed air. Inspect the test coupon to verify good adhesion and overall integrity of the phosphate coating. A coating of light oil may be applied to the completed coupon in order to prevent corrosion if a sufficient amount of time exists between processing and coating weight determination. Coupons shall be placed in a water tight container or plastic for storage and/or transportation. For process/line qualification, a completed Phosphate Qualification Test Traveler shall be completed for each processed coupon. Requirements for coating weight documentation and acceptance criteria are described in TSH-PQ-00.0003. Coating Weight Determination Procedure Determination of Coating Weight by Difference --The coating weight is determined by weighing the test coupon before and after dissolving the coating. Coupon Surface Area -The length (l), the width (w), and the thickness (t) of the test coupon shall be measured in three places as shown in Figure 1. The average of the three dimensions shall be used to calculate the surface area (S). The surface area of the hole in the coupon is not included in the calculation because the error created is negligible. Record the test coupon surface area.