Pink coloring after soaking a rr spike in vinegar. Any one knows why?

[cajundetector]

Soaked this spike that a found about 3 weeks ago. Been soaking for 3 days. Took it out and lo and behold, some type of pink patina Can’t find any answers online. If anyone has ever encountered this issue I would greatly appreciate your insight. Thanks

 

[Blackfoot58]

Interesting. US spikes were made with different “recipes” depending on the intended conditions. Carbon steel, High Carbon steel and Stainless steel. Possibly others as well. Maybe the composition variances caused the pinkish tone. I’ve not see this before.

 

[ticndig]

High-carbon railroad spikes are higher in copper than older soft-iron spikes,

Railroad Spike age clues

These contextual clues help in the identification and age determination of railroad spikes and other nails. Surrounding information helps guess age of any artifact.

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