ISO 15184:2020 Paints and varnishes — Determination of film hardness by pencil test

ISO 15184:2020 Paints and varnishes — Determination of film hardness by pencil test. 7.3 Preparation and coating Unless otherwise agreed, prepare each test panel in accordance with Iso 1514 and then coat it by the specified method with the product or system under test. 7.4 Drying and conditioning Dry (or stove) and age, if applicable, each coated test panel for the specified time under the specified conditions. Before testing, condition the coated panels at (23 ± 2) °C and a relative humidity of (50 ± 5) %, unless otherwise agreed, for a minimum period of 16 h. 7.5 Thickness of coating The thickness of the coating shall he as specified or as agreed between the interested parties. Determine the thickness of the coating by one of the procedures specified in ISO 2808. 8 Procedure 8.1 Carry out the test at a temperature of (23 ± 2) °C and a relative humidity of (50 ± 5) %, unless otherwise agreed. 8.2 Remove approximately 5 mm to 6 mm of wood from the point of each pencil using the special mechanical sharpener (5.3), being careful to leave an undisturbed, unmarked, smooth cylinder of pencil lead. 8.3 Flatten the tip of the lead by holding the pencil in a vertical position and moving the pencil back and forth over abrasive paper (5,4), maintaining an angle of 90. Continue until a flat, smooth, circular cross-section is obtained, free from chips or nicks in the edges. Repeat this procedure each time a pencil is used. 8.4 Place the coated panel on a level, firm, horizontal surface. Insert a pencil in the test instrument (Si.) and clamp it in position so that the instrument is horizontal, with the tip of the pencil resting on the surface of the paint film (see Figure 1). 8.5 Immediately after the tip of the pencil has come to rest on the coating, push the pencil in the direction away from the operator at a slow constant speed sufficiently long enough to perform a visual interpretation. 8.6 Unless otherwise agreed, inspect the coating after 30 s, using normal corrected vision, for marking of the kind defined in Clause 9. The damage can be assessed more easily after cleaning all fragments of pencil lead from the paint surface, using a soft cloth or swab of cotton wool (55) and an inert solvent. If this is done, take care that the solvent does...