Test Procedure of Dry Rubbing and Wet Rubbing by Crockmeter

Manual friction fastness tester is the most commonly used instrument for the textile industry to detect the color fastness of the fabric to dry and wet rubbing. The test procedures for dry rubbing and wet rubbing are as follow：

Dry rubbing:

1. Use the holding clamp to mount the specimen on the baseboard of the Crockmeter. The long direction of the specimen is parallel to the track of rubbing. Ensure the specimen lays  flat on the baseboard.
2. Two tests are performed, one along the direction of the warp/length and the other of the weft/width.
3. Mount a dry rubbing cloth flat over the end of the peg on the Crockmeter and hold it taut by means of the spring clip provided. Ensure that the rubbing cloth is not placed on the diagonal in the direction that the peg is moving.
4. Rest the finger on the specimen, ensuring that the spring clip is not in contact with the test specimen.  
5. Rub the specimen back and forth over a straight track 100mm + 8mm long for 10 complete cycles (i.e. 10 times back and forth) at a rate of 1 second for each cycle.
6. It may be necessary to stretch some fabrics on to the base of the Crockmeter, to prevent the fabric from rucking up.

Wet rubbing:

1. Wet out a rubbing cloth with distilled/deionised water to have about 100% pick up. A suitable method is as follows, however any method where the rubbing cloth picks up its own mass in water is acceptable.
2. It is important to understand the quality of water used here. As per standards, Grade 3 water is a must.  
3. Weigh the dry rubbing cloth and then thoroughly wet out in distilled/de-ionised water, squeeze the wet rubbing cloth between blotting paper and re-weigh on the balance. Make adjustments as necessary by either blotting off more water or re-wetting.
4. Use the following method to calculate 100% pick up of water - original weight of rubbing cloth x 2 (65% in AATCC method)
5. Carry out the appropriate test as the procedure for dry rubbing.
6. Allow the tested rubbing cloth to dry at room temperature.

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