ASTM TEST SUMMARIES
D7091-05 Standard Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to Ferrous Metals and Nonmagnetic, Nonconductive Coatings Applied to Non-Ferrous Metals
This practice describes the nondestructive measurement of the dry film thickness of nonmagnetic coatings applied to the surface of ferrous metals using magnetic gages and the nondestructive measurement of the dry film thickness of electrically nonconductive, nonmagnetic coatings applied to the surface of nonferrous metals using eddy current gages.
Coating thickness can be measured using a variety of gages. These gages are categorized as “magnetic pull-off” and “electronic.” They use a sensing probe or magnet to measure the gap (distance) between the base metal and the probe.
Note: Gages which measure coating thickness using an ultrasonic principle may also be used to measure the thickness of coatings applied to metal surfaces. Test Method D 6132 should be referenced for this application.
D2794-93(2004) Standard Test Method for Resistance of Organic Coatings to the Effects of Rapid Deformation (Impact)
This test method covers a procedure for rapidly deforming by impact a coating film and its substrate and for evaluating the effect of such deformation. A standard weight is dropped from an increasingly higher distance to form an indentation in the sample panel and reach failure. Failure is seen a cracks in either if the intrusion (direct) or extrusion (indirect) which can be detected visually, chemically or electrically (pin hole detector).
This test method should be restricted to testing in only one laboratory when numerical values are used because of the poor reproducibility of the method. Inter-laboratory agreement is improved when ranking is used in place of numerical values.
D522-93a(2001) Standard Test Methods for Mandrel Bend Test of Attached Organic Coatings
These test methods cover the determination of the resistance to cracking (flexibility) of attached organic coatings on substrates of sheet metal or rubber-type materials.
After curing the coated panels are bent over a mandrel and the resistance to cracking of the coating is determined. Test Method A used a conical mandrel and Method B uses a cylindrical mandrel. Mandrels vary in diameter from 1/8″ – 1 ½”. The coating flexibility value is represented by the mandrel diameter at which no cracks are seen in the coating.
D3359-02 Standard Test Methods for Measuring Adhesion by Tape Test
These test methods cover procedures for assessing the adhesion of coating films to metallic substrates by applying and removing pressure-sensitive tape over cuts made in the film.
Test Method A (X-cut) is primarily intended for use at job sites.
Test Method B (Lattice-cut) is more suitable for use in the laboratory. Test Method B is not considered suitable for films thicker than 5 mils (125µm).
These test methods are used to establish whether the adhesion of a coating to a substrate is at a generally adequate level. More sophisticated methods of measurement are available to measure adhesion with a higher degree of accuracy
D3363-05 Standard Test Method for Film Hardness by Pencil Test
This test method covers a procedure for rapid, inexpensive determination of the film hardness of an organic coating on a substrate in terms of drawing leads or pencil leads of known hardness. (6H – Hardest; 6B – Softest)
A coated panel tested using a pencil held firmly against the film at a 45° angle and pushed away from the operator in a ¼” stroke. The process is started with the hardest pencil and continued down the scale of hardness to either of two end points:
• Pencil Hardness – the pencil that will not cut into or gouge the film or,
• Scratch Hardness – the pencil that will not scratch the film
D4060-07 Standard Test Method for Abrasion Resistance of Organic Coatings by the Taber Abraser
This test method covers the determination of the resistance of organic coatings to abrasion produced by the Taber Abraser on coatings applied to a plane, rigid surface.
Because of the poor reproducibility of this test method, it should be restricted to testing in only one laboratory when numerical abrasion resistance values are to be used. Interlaboratory agreement is improved significantly when rankings of coatings are used in place of numerical values.
Abrasion resistance is calculated as loss in weight at a specified number of cycles as a loss of weight per cycle, or as number of cycles required to remove a unit amount of coating thickness.
D3170-03 Standard Test Method for Chipping Resistance of Coatings
This test method covers the determination of the resistance of coatings to chipping damage by stones or other flying objects.
Standardized road gravel is projected by means of a controlled air blast at the coated specimens. Tests can be made more severe by performing them at lower temperatures. The resultant chipping effect is evaluated by comparison with a set of photographic standards.
D523-89(1999) Standard Test Method for Specular Gloss
This test method covers the measurement of the specular gloss of nonmetallic specimens for glossmeter geometries of 60, 20, and 85°.
The 60° geometry is used for comparing most specimens and for determining when a 20° geometry may be more applicable.
The 20° geometry is advantageous for comparing specimens having 60° gloss values higher than 70.
The 85% geometry is used most frequently for comparing specimens that have 60° gloss values lower than 10.
D2244-07 Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
This practice covers the calculation, from instrumentally measured color coordinates based on daylight illumination, of color tolerances and small color differences between opaque specimens such as painted panels, plastic plaques, or textile swatches.
For product specification, the purchaser and the seller shall agree upon the permissible color tolerance between test specimen and reference and the procedure for calculating the color tolerance. Each material and condition of use may require specific color tolerances because other appearance factors, (for example, specimen proximity, gloss, and texture), may affect the correlation between the magnitude of a measured color difference and its commercial acceptability.
D1308-02e1 Standard Test Method for Effect of Household Chemicals on Clear and Pigmented Organic Finishes
This test method covers determination of the effect of household chemicals on clear and pigmented organic finishes, resulting in any objectionable alteration in the surface, such as discoloration, change in gloss, blistering, softening, swelling, loss of adhesion, or special phenomena.
Three test methods are available;
Spot Test, Covered – The reagent is placed on the test surface and immediately covered with a watch glass.
Spot Test, Open – The reagent is place on the test surface and left uncovered
Immersion Test – Test specimen is immersed in the reagent.
These test methods provide a means for comparing the relative performance of the coating system.
D2247-02 Standard Practice for Testing Water Resistance of Coatings in 100% Relative Humidity
This practice covers the basic principles and operating procedures for testing water resistance of coatings by exposing coated specimens in an atmosphere maintained at 100 % relative humidity so that condensation forms on the test specimens.
Selecting the duration of the test varies the exposure condition. Water permeates the coating at rates that are dependent upon the characteristics of the coating. Any effects such as color change, blistering, loss of adhesion, softening, or embrittlement are observed and reported.
Note- Results obtained from the use of 100% Humidity Test in accordance with this practice should not be represented as being equivalent to a period of exposure to water in the natural environment, until the degree of quantitative correlation has been established for the coating or coating system.
B117-07 Standard Practice for Operating Salt Spray (Fog) Apparatus
This practice covers the apparatus, procedure, and conditions required to create and maintain the salt spray (fog) test environment. This practice does not prescribe the type of test specimen or exposure periods to be used for a specific product, nor the interpretation to be given to the results.
Preparation of samples and evaluation of results are described in:
ASTM D610-01 Standard Test Method for Evaluating Degree of Rusting on Painted Steel Surfaces
ASTM D1654-05 Standard Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments
D1014-02 Standard Practice for Conducting Exterior Exposure Tests of Paints and Coatings on Metal Substrates
This practice covers procedures to be followed for direct exposure of exterior paints and coatings to the environment when applied to metal surfaces. When originators of a weathering test have the actual exposure conducted by a separate agency, the specific conditions for the exposure of test and control specimens should be clearly defined and mutually agreed upon between all parties.
Test results are dependent on the test site location because of differences in solar radiation, amount of precipitation, temperature, pollutants and other factors. Therefore, it cannot be assumed that results from one location are useful in predicting results in another location. Exposure in several locations with different climates is recommended.
D4141-01 Standard Practice for Conducting Black Box and Solar Concentrating Exposures of Coatings
This practice covers accelerated outdoor exposure procedures for evaluating the exterior durability of coatings applied to substrates as follows:
Procedure A – Black Box Exposure is performed in a box constructed per Practice G7 and is positioned so that the surfaces of the test specimens are 5° from the horizontal, facing the equator.
Procedure B – Discontinued
Procedure C – Fresnel Reflector Rack Exposure is conducted in a rack that follows the sun, concentrates the sunlight on the specimen by means of mirrors. Samples are periodically cooled by spraying with high purity water. Practice G90 provides a detailed description of the apparatus.
This standard does not cover all the procedures that are available to the user for accelerating the outdoor exposure of coatings. Other procedures have been used in order to provide a particular effect; however, the two procedures described here are widely used.