Acid reaction with metals as identification

A discussion started in 2004 but continuing through 2019

2004

Q. I work in the aircraft industry and need to find out what metals will react with various acids. this is purely for identification purposes. I am trying to find what acids are used, when applied on metals, e.g., aluminium, magnesium, silver, copper, etc. will react by showing a colour identification similar to litmus paper. an example of this is finding metal in a oil filter and trying to identify what metal it is to locate the component which is breaking up.
hope you can help...thanks

John Aide
student - Sydeny, NSW, Australia

affil. link
"Rapid Spot Testing"
from Abe Books
or

A. I'm not sure if I really understand, but you can get a copy of "Rapid Spot Testing of Metals, Alloys, and Coatings" from Metal Finishing Information Service.

Ted Mooney, P.E.
finishing.com - Pine Beach, New Jersey
Striving to live Aloha

Spot tests for plating type identification

November 30, 2019

Q. Hi, I'm restoring some 60's Triumph motorcycles which have different plating on the various parts. After 50+ years of corrosion I find it hard to determine what plating is on some of the parts, chrome, nickel, or cadmium.

Is there any way to determine what type of plating is present such as acid reaction, scratch resistance, something else?
Thanks

eric thies
restorer - Grand Ledge, Michigan, USA

December 2019

A. Hi Eric, if you had access to sophisticated test equipment like beta-backscatter and x-ray fluorescence machines it might be relatively easy. I hate to bear bad tidings but I think you'll find efforts to track down what plating Triumph put on them more rewarding than trying spot tests. The problem with spot tests is that it almost always takes two, and often three or more tests to identify the plating; and when it's worn through, so the substrate participates in the reaction, it can be especially hard. It's probably possible, but probably too much effort to be realistic :-)

Regards,

Ted Mooney, P.E. RET
finishing.com - Pine Beach, New Jersey
Aloha -- an idea worth spreading

December 4, 2019

Thanks. Looks like more research for me.

eric thies [returning]
- Grand Ledge, Michigan, USA

adv.
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