White powder corrosion

SkipperJohn

SkipperJohn

Well-known member
Several of my officer and private purchase Pickelhauben have a white powder type of corrosion on gilded brass components. This appears on Wappens, dart and egg pearlrings, and occasionally on spike base mounting stars. It never occurs on heavier metal components like spike bases, spikes, or visor trim. This "powder" is white and is only found in tiny crevices on gilded parts. I have dusted it, washed it with water, used a Q-tip with alcohol to wipe it, and (I really hate to do this) brushed at it lightly with a soft toothbrush, and it doesn't go away. It is not dried polish and it is more prevalent on "newer" helmets, 1912-1915. My older gilded helmets, 1871 era, show no sign of it. I talked to a metallurgist and he said that it sounded like zinc oxidation, but none of my Hauben have gilded zinc fittings.
Does anybody know what this is?
Does anybody know how to get rid of it?
Does it degrade the gilding or base metal?
Any advise is appreciated.
John :-s

PS. I have never seen this on an issue helmet, never on a raw metal (lacquered or unlacquered brass) fitted helmet, or on a helmet with silver nickel fittings.
 
It does sound like some type of oxidation. You could try cleaning it off then seal the area with a wax, lite oil,or petroleum jelly and see if it comes back. Any type of oxidation is damaging the metal as it is changing the metal into something else. There are many factors that could be causing this. The gilding (gold) on a base metal and the chemicals used in making the body of the helmet may all be reacting to one another. Also the environment where the helmet is stored may have influence on a reaction. If you believe it to be a real problem, you may do best to have the powder tested to see what it actually is.
 
Tony without Kaiser said:
SkipperJohn said:
he said that it sounded like zinc oxidation, but none of my Hauben have gilded zinc fittings.
Click to expand...

Oh I think you do John. What you describe is a sure sign of mixed zinc fittings.
Click to expand...

Would this be an alloy which included zinc or raw zinc that was plated? This can only be seen on Wappens and pearlrings. I am unaware of Wappens being stamped out of thin zinc and then plated. I know that some spikes, crucifixes, and round bases were made of zinc and then gilded but those are much heavier and thicker pieces. Also in areas where the gilding has worn off, the base metal appears to be brass. Was brass mixed with zinc in the war years to reduce cost or save on brass?
John
 
I got my answer. Of course brass was mixed with zinc since brass is an alloy of copper and zinc. I talked to a professor at the college and he called this "dezincification" and says that it happens over time in base (high Ph) environments. It is not as degrading as the green verdigris but will probably cause pitting over an extended time. Electrolysis increases the formation. This powder is actually the zinc escaping from the alloy. The higher the amount of zinc in the alloy the faster it will occur and the more degrading it is (he used the example of white corrosion on brass plumbing fixtures which are generally 15% zinc or higher). Anyway, he said to take a Q-tip dipped in vinegar and lightly go over the area making sure the vinegar got into all of the crevices, let stand for about ten minutes, then rinse with warm water. I tried this on a pearlring and, lo and behold, the white powder was gone.
Hope this helps someone,
John :)
 
Thanks John, for tracking this down, now we have the answer. I did not participate in the discussion as I had no clue as to what was going on.
 
Yes, it looks similar. It is kind of hard to tell, but it is definitely not polish residue. Most of what I saw was around the pearl ring and there was some around the stars. I had some on Wappens that looked like a fine powder in the smallest details, like the feather accents. I used the vinegar and warm water trick and it went away. I have noticed that some of it is beginning to reappear, but this is only on the pearl ring. What I saw on my helmets was very fine, no clumps what-so-ever. I don't know if what you are seeing is the same, but you could try the vinegar. Even if it doesn't work it won't hurt anything.

John :)
 
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