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Saving Private Iron, part four: lacquer beware

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#1 lee14

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Posted 17 February 2024 - 01:37 PM

This etched specimen is a 226g Gibeon, the only slice I've kept from the first Gibeon I cut, more than twenty years ago. Gibeons are known to be exceptionally stable, rarely needing special attention. Aside from an initial application of G-96 right after it was etched, the piece remained on the display shelf for many years in completely pristine condition. Several years ago I decided to bring it along to a number of outreach sessions. Expecting it to be handled quite a bit, I gave it several coats of lacquer to ward off fingerprints that could potentially leave marks on the etch. The lacquer also seems to improve the contrast of the etch. Over time though (years), a couple of corrosion streaks appeared.

 

Whether there was trapped moisture present in the plate boundaries, or the lacquer penetrated and somehow reacted there, I'm uncertain. The rust spots are stable, no changes have occurred since they first appeared. They are an annoyance though, on an otherwise perfect specimen. Similar pieces have only been given the G-96 treatment and they remain rust free. Recommendation; avoid sealants that can cause issues that are so readily avoided.

 

Lee

 

226g Gibeon.jpg

 

 


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#2 scottinash

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Posted 17 February 2024 - 01:43 PM

Thank you for taking the time to share this excellent information/tutorial.


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#3 lee14

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Posted 17 February 2024 - 03:41 PM

The pic above looks pretty severe, but the rusted area is actually pretty small in relation to the entire slice. It's cropped to allow for more detail, but I should have included a shot of the whole slice to keep things in proportion.

 

Lee

 

226g Gibeon full.jpg


Edited by lee14, 17 February 2024 - 04:08 PM.


#4 leonardovaller

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Posted 19 February 2024 - 02:00 AM

What harm or benefit would it do to a specimen of Gibeon if I spray anti corrosive lubricant once-monthly?


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#5 lee14

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Posted 19 February 2024 - 05:12 AM

What harm or benefit would it do to a specimen of Gibeon if I spray anti corrosive lubricant once-monthly?

It might depend on the specific type, but I suspect no harm at all. The Gibeon above was treated with an application of G96 after it was etched, and never treated again until I cleaned the oil from the surface and sprayed on the lacquer. So it went about ten years untreated and showed no degradation at all. Gibeon is particularly stable, and this is a very humid  environment. I think the G96 penetrated the micro fissures, and either displaced any moisture or prevented it from entering. The lacquer either trapped atmospheric moisture or released some as it cured.

 

The only potential risk I see from only frequent applications would be if the lubricant contained a component that actually removed (as opposed to preventing) corrosion. The etched layer is very thin and could be damaged by any chemical that 'cleans' iron by removing a few surface molecules. Etching with nitol affects the kamacite, but leaves the taenite untouched. Unless your piece shows evidence of corrosion, it's probably best left alone. If you use G96 gun oil or an equivalent, allowing time for penetration and then wipe off the excess, a single application will last a very long time.

 

Lee


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#6 leonardovaller

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Posted 21 February 2024 - 01:02 AM

It might depend on the specific type, but I suspect no harm at all. The Gibeon above was treated with an application of G96 after it was etched, and never treated again until I cleaned the oil from the surface and sprayed on the lacquer. So it went about ten years untreated and showed no degradation at all. Gibeon is particularly stable, and this is a very humid  environment. I think the G96 penetrated the micro fissures, and either displaced any moisture or prevented it from entering. The lacquer either trapped atmospheric moisture or released some as it cured.

 

The only potential risk I see from only frequent applications would be if the lubricant contained a component that actually removed (as opposed to preventing) corrosion. The etched layer is very thin and could be damaged by any chemical that 'cleans' iron by removing a few surface molecules. Etching with nitol affects the kamacite, but leaves the taenite untouched. Unless your piece shows evidence of corrosion, it's probably best left alone. If you use G96 gun oil or an equivalent, allowing time for penetration and then wipe off the excess, a single application will last a very long time.

 

Lee

Thank you so much. I've been doing that from a while.


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