1) Apparatus: Elmendorf Tearing Tester, based on Tappi Method T 414.
2) Select the four trapezoidal pieces with the lowest basis weights out of the five cut handsheets and gently tap them on the table to align them. Load the stack (with the shorter flat edge on the bottom) into the clamps approximately 1 cm away from the edge/corner of the shorter flat edge. You need to perform 4 tears so align them evenly.
3) Select mNt and 4 PLIES for the test.
4) Lock the clamps by flipping the switch up, then use the swing-in knife to precut the sheets. Release the pendulum by depressing the Pendulum Stop (see figure 12). Note: when you release the pendulum, you must depress and hold the metal bar/level (Pendulum Stop) at the base of the machine. Hold the bar down the entire time! When the pendulum returns, catch it and release the bar to lock it back in place. Record the value.
Figure 12: Sequence of tear test. On the left, clamp and precut specimens; in the middle, depress the Pendulum Stop to let go of the pendulum to tear the specimen; on the right, pendulum swings to tear handsheet pad.
5) Repeat for the other 3 tears (see figure 13). Note: acceptable tears should be quite straight and perpendicular to the flat edges. Once you are done, press A for average; S for standard deviation; D for difference of highest and lowest; I for numbers of tears and sequence of individual result; RC for recall latest result; P for printer; CM for clear memory.
Figure 13: Sequence of second tear test: clamp the larger pad that is left from the tear, precut, then depress the Pendulum Stop to let go the pendulum.
6) If your result drifts away from normal range, please check the quality of handsheets and the tear patterns. If nothing is wrong with handsheet and machine setting, please call lab technician to carry out calibration check.
