Apparatus for Measuring Adhesion of Dried Films

Abstract

Minor adjustments which may be made with each assembly are: moving the position of the barrel by sliding it through the pipe clamps, C, until proper release of the air is made at the end of the stroke, increasing the number (but not the size) of the holes where air is released, increasing the size of the air inlet, and adjusting the tension and the position of the platform. When correctly assembled and regulated, the machine should start promptly with admission of air a t d, run continuously, and require no further adjustment for loads which vary from a gram to 1.5 kg. Higher weight limits have not been tried.The arrangement given in this description is for an apparatus in which only a few changes have been made with the starting materials. 1 'Since the stroke in this machine need not be more than 2 inches (5 cm.) long a t the most, it should be possible to cut down the length of the barrel and piston rod to proportionate size, reducing the apparatus to almost half the space formerly occupied. It should also be possible to mount the barrel under the shaking platform by use of suitable connections. The use of smaller springs will give a longer stroke. The same system of springs may be used with some advantage on motor-driven shakers. ACKNOWLEDGMENTThe author is indebted to E. C. Curtis for valuable aid in the construction and assembling of this apparatus.

Painting Zinc and Zinc Alloy Surfaces

“…(1) Edwards, J. D., V. S. Patent 1,946,152 (Feb. 6, 1934). (2) Edwards, J. D.. and Wray, R. I., Ind.…”

“…From a practical point of view, we may choose any combination of two alternative positions-namely, (1) use a primer with mediocre adhering qualities and stress surface treatment of the zinc, or (2) use improved primers that make it unnecessary to stress surface treatment. Now that the paint chemist is giving more serious attention to the subject of primer formulation, there has been a distinct shift toward the second position and we shall undoubtedly see more rapid progress in that direction, with less and less need for the precautions that have been advocated in the past.…”

“…( 2) Treating with an acidulated toluene-alcohol-carbon tetrachloride mixture, as described in the previous publication (5). (This mixture should preferably be made up and used as wanted.…”

“…Any attempt at an explanation of initial adherence and adherence retention leads to involved theoretical consideration of ( 1) selective adsorption, (2) progressive changes in the paint film, (3) disturbance of the oxide film normally existing at the surface of the metal, and ( 4) electrolytic attack of the metal. These topics cannot all be adequately covered in one paper, yet even limited discussion of them here may aid in giving direction to the work on finishing systems with improved initial adherence and adherence retention.…”