1、 FORD LABORATORY TEST METHOD BI 107-02 Date Action Revisions 2001 07 23 Revised Rev para 2 and 2B on page 2 R. Moore 1990 02 16 Printed copies are uncontrolled Page 1 of 4 Copyright 2001, Ford Global Technologies, Inc. DETERMINATION OF COLD CHECKING RESISTANCE TO EXTERIOR AUTOMOTIVE TOPCOATS Applica
2、tion This method is used to evaluate the resistance of paint films to cold checking when subjected to thermal stresses. Apparatus and Materials Required Humidity Cabinet Cabinet shall be capable of maintaining 100 % relative humidity and a temperature of 38 +/- 2 C (FLTM BQ 104-02). Mechanical Conve
3、ction Oven Oven shall be capable of maintaining temperatures up to 190 +/- 2 C. Cold Box (minimum size - 0.1 m3) The cold box shall have the capability of maintaining a temperature of 30 +/- 2 C. A box with door opening at the top is preferable in order to minimize rapid changes in box temperature w
4、hile panels are placed inside. Paint Thickness Measuring Device According to FLTM BI 117-01 - Permascope with constant pressure probe or equivalent. Sources (or approved alternative): The Paul N. Gardner Company (Gardco) Helmut Fischer GMBH & Company www.helmut- FORD LABORATORY TEST METHOD BI 107-0
5、2 Page 2 of 4 Copyright 2001, Ford Global Technologies, Inc. Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/- 2 C and 50 +/- 5 % relative humidity for not less than 24 h prior to testing and tested under the same
6、 conditions unless otherwise specified. Preparation of Test Panels 1. Steel Test Panels Test panel preparation must conform to FLTM BI 103-02 or as specified in the applicable Engineering Material Specification. 2. Primer/Enamel A. Electrocoat Primer Coat panels with the current production electroco
7、at primer applied at the assembly plant or as specified in the Engineering Material Specification. There will be no wiping or sanding of the electrocoat primer. B. Primer Surfacer Using panels from Para A as required, apply current production spray primer to a dry film thickness of 25 micrometers (3
8、0-40 micrometers for high stone resistant primers) and bake as specified in the Engineering Material Specification. There will be no wiping or sanding of the Primer Surfacer. C. Procedure for Use of Conventional Enamels Using three primed panels from Para B, apply enamel by spray to a dry film thick
9、ness of 38 - 51 micrometers. Bake one panel each at the minimum bake, standard bake and maximum bake as specified in the Engineering Material Specification. There will be no wiping or sanding of the enamel. Repeat the procedure until the required total film thickness is achieved using no more than 3
10、 repair coats on each panel. FORD LABORATORY TEST METHOD BI 107-02 Page 3 of 4 Copyright 2001, Ford Global Technologies, Inc. D. Procedure for Use of Clearcoated Enamels Using three primed panels from Para B, apply basecoat portion by spray to a dry film thickness of 15 - 20 micrometers. Flash for t
11、hree minutes. Apply clearcoat portion by spray to a dry film thickness of 40 - 50 micrometers. Bake one panel each at the minimum bake, standard bake and maximum bake as specified in the Engineering Material Specification. There will be no wiping or sanding of enamel. Repeat the procedure until the
12、required total film thickness is achieved using no more than 3 repair coats on each panel. E. Procedure for Enamel with Catalyst Use same procedure as in Para C or D (as required) with the following exceptions: 1. Incorporate catalyst as specified by the Engineering Material Specification. 2. A mini
13、mum of one panel only is required. 3. Use bake schedule as specified by the Engineering Material Specification for cure of catalyzed enamel. Procedure for Cold Checking 1. Aging of Test Panels Immediately prior to being placed in test, age the panels for either 72 hours at 23 +/- 2 C or for 16 hours
14、 at 25 +/- 2 C in a mechanical convection oven. 2. Humidity (16 hr) Subject panels to humidity resistance testing per FLTM BQ 104-02. 3. Cold Box at -30 +/- 2 C (4 hrs) Remove panels from the humidity cabinet and immediately place in cold box for four hours. 4. Room Temperature, 23 +/- 2 C (2 hrs) R
15、emove panels from cold box and allow to stand at 23 +/- 2 C for two hours. FORD LABORATORY TEST METHOD BI 107-02 Page 4 of 4 Copyright 2001, Ford Global Technologies, Inc. 5. Mechanical Convection Oven, 65 +/- 2 C (2 hrs) Place panels in a mechanical convection oven at 65 +/- 2 C for two hours. 6. E
16、xamination of Panels for Cracking Remove panels from oven and examine for evidence of paint cracking. Failure usually appears as a series of irregular hairline fractures of the paint coating. Evaluating and Reporting of Results Paint must pass the number of cold checking cycles required by the Engin
17、eering Material Specification. If paint fails prior to this, it is considered to be unsatisfactory. Report the cycle at which the failure occurs. 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.
