ASTM A630:16 pdf download

ASTM A630:16 pdf download.Standard Test Methods for Determination of Tin Coating Weights for Electrolytic Tin Plate.
5. Apparatus
5.1 The detinning cell consists essentially of two cathodes of carbon rod, the sample that serves as an anode, and a beaker of dilute hydrochloric acid electrolyte. The carbon rods (6 by 0.25 in. or 152 by 6.35 mm, encased in porous porcelain thimbles) are suspcnded from a suitable frame about I in. (25 mm) apart. A small glass-enclosed magnet is attached to the frame in such a manner that it will hold the sample suspended midway between the two cathodes. A movable platform permits the beaker of electrolyte to be brought up around the assembly so that the sample will be completely immersed.
5.2 A source of direct current that can be regulated to supply up to 3 A at 3 to 5 V through the deplater is required.
5.3 Although regular laboratory glassware can be used, it is advisable to use automatic dispensing pipets or hurets, a motor-driven stirrer for titrations, and a timing switch when large numbers of determinations are to he made.
5.4 Precautions—The apparatus must he kept in continuous operation to prevent iron in the solution adhering to the porous cells from oxidizing and subsequently liberating iodine from the potassium iodate-potassium iodide solution. If the instrument has been idle for some time, it is necessary to remove the ferric iron by running a disk of tinplate through the regular procedure before test samples are run.
6. Reagents
6.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated. it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available.4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.
6.2 Water—Deionized or distilled water having a volume resistivity greater than 1 Mcm at 25°C as determined by Nonreferee Method of Test Methods Dl 125.
6.3 Hydrochloric Acid (1.7 to 2.0 N—Add 1 part of concentrated hydrochloric acid (HC1, sp gr 1.19, 36.5 to 38.0%) to 5 parts of water and mix well.
Complete details and drawings of the apparatus are contained in U. S. Patent No. 2.455.726 entitled Method for Electrolytic Stripping and Determination of Plating Metals.” A suitable commercial supplier of the apparatus has been ftund to be the Wilkens-Anderson Company of Chicago.