Excerpt from Proceedings of the Fifty-Fifth Annual Convention of the American Railway Engineering Association, Construction and Maintenance Section, Engineering Division, Association of American Railroads: Held at the Palmer House, Chicago, Illinois, March 13, 14 and 15, 1956For the past three years the aar research staff has been cooperating with the Steel Structures Painting Council to determine the suitability - for painting - of chemically cleaned and pretreated surfaces in comparison with surfaces cleaned by hand-chipping and Wire-brushing methods, and to evaluate the performance of a number of paints and coatings. For this investigation portions of two through-plate girders of a railroad bridge in Chicago (see Fig. 1) were first chemically cleaned by use of a flush-off paint stripper and steam, and then pretreated with a proprietary cold phosphate rust remover. Other portions were cleaned by hand chipping and wire brushing. Six primers were applied to both types of cleaned surfaces, and one-half of each primed surface was top coated with a black finish paint. A detailed inspection was held on June 29, 1954.The chemically cleaned and pretreated surfaces were inferior to the hand cleaned surfaces, but a chemically cleaned surface without the pretreatment was slightly superior to a similar hand-cleaned surface. The best primers were Paint No. 1 and Paint No. 2 (see Fig. Some of the primers were very poor. Asphalt oil (paint No. 7) when later top-coated with asphalt bridge cement (paint No. 8) and a grease compound (paint No. 9) gave almost complete protection to hand-cleaned surfaces. But no paint or coating was satisfactory over very heavy rust scale.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.