ASTM D3708 Standard Test Method for Weight of Wax Applied During Curtain Coating Operation
6. Apparatus
6.1 Sample Trimming Equipment - A suitable trimming board or template arrangement equipped with a razor edge knife for even cutting of specimens to the required size with parallel edges.
6.2 Measuring Rule, steel-edged, for measuring the size of specimens to within 0.5 mm.
6.3 Test Paper - Any good quality typing bond with about 25 % cotton fibers approximately 200 by 300 mm (8 1/2 by 11 in.).
6.4 Pressure-Sensitive Tape, to attach the test paper to the corrugated carrier board.
6.5 Carrier Board - Production uncoated corrugated board, not less than 450 by 750 mm (18 by 30 in.). Die cut, slotted, and printed box blanks are acceptable.
6.6 Analytical Balance, capable of reproducing weighings to the nearest 0.001 g.
7. Sampling and Test Specimens
7.1 Prepare test blanks by folding the 200 by 300-mm (8 1/2 by 11-in.) sheets of the test paper in half in the 300-mm dimension. Assure that all folded edges are approximately superimposed on each other. Crease the fold firmly with the fingers. Then place the folded sheet about in the center of a suitable piece of corrugated carrier board and tape it firmly to the board around its entire periphery with pressure-sensitive adhesive tape.
7.2 Prepare duplicate test blanks (carrier boards with attached folded sheets as described in 7.1) for each test unit. Prepare a supply of test blanks ahead of time and keep them available at the machine for determining the amount of wax applied.
NOTE 2 - The test sheets do not require preconditioning since the paper is only a carrier for the wax, and variations are eliminated in the weighing procedure.
NOTE 3 - If the uniformity of application of wax film across the width of the curtain coater is being checked, the folded test sheet can be placed near one of the side edges of the corrugated carrier board to cover the maximum width of curtain. In no case should the test sheet be placed closer than 150 mm (6 in.) to either side edge of the carrier board.
