Work Item
ASTM WK84191
Revision of E407-07(2015)e1 Standard Practice for Microetching Metals and Alloys
Rationale
Full review of existing standard to make editorial corrections and new items, including the issue outlined below
Excerpt from E407
7.2.1 Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type IV of specification D1193. Experience has shown that the quality of tap water varies significantly and can adversely affect some etchants.
Change to:
7.2.1 Unless otherwise indicated, references to water shall be understood to mean distilled water. Experience has shown that the quality of tap water varies significantly and can adversely affect some etchants.
There is no data to be found suggesting grocery store distilled water has any effect on cleaning or etching in metallographic environments that Type IV of specification ASTM D1193 distilled water mitigates.
However, there is a significant upcharge for the Type IV of specification ASTM D1193 distilled water to the tune of 17 times or more than the cost of regular distilled water. See the images below. Given that laboratories captive or commercial are performing these tests to make a profit straddling them with this extra cost without any evidence that it makes a significant difference in results is unreasonable.
The statement:” Experience has shown that the quality of tap water varies significantly and can adversely affect some etchants.” justifies not using tap water. It does not address the need to use Type IV of specification ASTM D1193 distilled water over the normal distilled water available from our local stores or venders at a reasonable cost.
Work Item Status
Date Initiated: 11-14-2022
Technical Contact: Mike Keeble
Item: 000
Ballot:
Status: