1、 FORD LABORATORY TEST METHOD BI 151-01 Date Action Revisions 2001 03 20 Revised Editorial no technical change A. Cockman 1993 05 18 Printed copies are uncontrolled Page 1 of 3 Copyright 2001, Ford Global Technologies, Inc. PENCIL HARDNESS OF PAINT FILMS Application This method is used to determine t
2、he hardness of a dry or cured paint film, synthetic resins or other film forming substances in terms of pencil hardness. This test should be run where other hardness tests cannot be performed for reasons of film thickness, properties of the underlying materials or due to the dimensions of the part u
3、nder test. The method is virtually non-destructive in that the small mark made can be removed by polishing. Apparatus Required 1. Test Instrument The Wolff-Wilborn Model 291 supplied by: Pearson Panke Equipment Ltd. A. M. Emichsen Gmbh. 1-3 Halegrove Gardens 587 Hemo-Sundwig London N.W.7 3LR Westfal
4、en, Germany 819 593232 2372 6431 (81) 959-5613 (49) 202-83060 This instrument is so arranged that the pencil is drawn over the surface at a 30 angle with a load of 300 grams on the point. 2. Pencils Seventeen pencils, graded from 6B to 9H are used (Faber-Castell). Note: See Technical Description and
5、 Operating Instructions 291/E. Procedure Conditioning: All parts must be conditioned before testing for 72 hours minimum at 23 +/- 2 C, and a relative humidity of 50 +/- 5 % or if not possible conditions must be stated. FORD LABORATORY TEST METHOD BI 151-01 Page 2 of 3 Copyright 2001, Ford Global Te
6、chnologies, Inc. 1. Sharpening Pencils The point is sharpened in a pencil sharpener and then it is rounded off by rotating it on a piece of rough paper (not sand or glass paper) turning the pencil constantly and holding it approximately 40 to the horizontal. Sharp edges are naturally to be avoided.
7、2. Fitting Pencils into the Test Instrument The pencil is set in the holder so that the point is directly below the pointer (see Figure 1). 3. Estimating Hardness The holder with a pencil estimated to be too soft to mark the paint is drawn over the surface by means of the handle (see Figure 1). The
8、surface is examined to determine whether the pencil has made an impression on the paint. The test is repeated with increasingly harder grades of pencil until a noticeable impression is left on the surface. Evaluation The hardness is reported as the hardest grade of pencil that does not make an impre
9、ssion on the surface. Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in its facilities. FORD LABORATORY TEST METHOD BI 151-01 Page 3 of 3 Copyright 2001, Ford Global Technologies, Inc. PENCIL HARDNESS OF PAINT FILMS Figure 1
