Worn-off dates on Buffalo nickels... a new idea?

Does anyone have an infrared camera? Like the ones that firefighters use to "see" victims in a smoky room or that house inspectors use to look for hot/cold escaping through poorly-sealed windows, etc.

Since the metal is a different density where the date has been stamped, would the date show up if the coin were gently heated?

 

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Probably not, but maybe Jim @desertgem would know.

Chris

 

Sounds like an interesting theory..

but for some reason you've got me thinking of Hot Buffalo Chicken Wings instead!

 

I'm not trying to be facetious but is it really worth all that trouble when you can buy circulated pieces with dates for little money?

 

What about that date restoring acid that was so popular about 60 years ago? I forgot what they called it, but many coin collectors dabbed a small amount on buffalo nickels and standing lib. quarters where the date was, and the acid would slightly reveal the date.

 

But that just makes the coin look ugly. I know you might have a rare date or something but I personally think it makes the coins look really bad.

 

No offense taken. Mostly interested in this for the rare chance of finding key dates. That would make it worthwhile, I think?

Plus it wouldn't "scar" the coin like the Nic-a-date does.

 

I know that FLIR systems can cost multiple tens of thousands of dollars, at least 2-3 years ago. Even at mid to high 4 figures you gotta think that's pretty expensive to find a date that youll never really see? Would you send that camera in with your coin submission? JK obviously.

Another way to think of it is an LCS that won't invest in those XRF guns to test precious metals. A lot still just use acid testing. Nic-A-Date, while damaging the coin, does bring the date up permanently. So it's basically cost vs. benefit IMO. As a purely coin/scientific pursuit it sounds awesome though, if possible.

 

Infrared camera detect differences in temperature, not density (or taste).

 

But if the density is different, it would heat up at a different rate, wouldn't it?

 

They have minute differences in density and metals have extremely high heat transfer rates and relatively low heat capacities (the amount of heat it takes to raise the temperature of the material). I seriously doubt you could do anything to see the differences.

 

Ah well. Back to nic-a-date. ;-)

What about Superman's x-ray vision...?

 

Rlm is in the right ball park, infrared is a very low resolution medium compared to higher visible spectrum or above. Perhaps high level IR cameras such as the astronomical telescopes in SPITZER or HUBBLE satellites, but since they operate at near zero degree K contrast, there is a lot of contrast. On earth where the difference would be so small due to the size of the date, and how fast it would warm to equality with the rest of the coin, I do not believe it is currently possible with consumer goods.

Besides how to convince someone you really have a 'rare date' determined by such a means?

 

Good point.

I guess once you knew, you could send it to a professional service? (They probably wouldn't lower themselves to this, though)

Or you could use nic-a-date but very carefully so as to minimize the scar?

 

Don't cops use a die penetrant and a UV light to bring out serial numbers of guns when they have been removed?

 

This thread is relevant to my interests.



I've actually got two thermal cameras, a version-one SeeK and a FLIR E4 modified to the same sensitivity and resolution as the E8 (320x240).

I've experimented with them quite a bit, but I haven't yet come up with the killer app for applying them to numismatics. Coin metals conduct heat well enough that it would be nearly impossible to get a detectable thermal gradient at the fine scale you're discussing, and you'd need some sort of macro-lens setup to see the fine detail anyhow. (I've got that on my to-do list, but it probably won't happen any time soon.) I thought silver coins in a sealed clad roll might show up as warm bands when heated gently along one side, but I haven't experimented with that yet, either; the whole "sealed roll" scene doesn't especially tempt me any more.

I've wished I still worked at a lab with X-ray microscopy equipment. It seems plausible that X-ray diffraction would reveal a hidden date, possibly even in silver (which doesn't really reveal dates with chemical etching). That's not something I'm likely to undertake at home, though. There are hobbyists out there who work with X-ray equipment, but I'm getting a bit too old and cautious for that.

 

Seems also that you would need a high speed movie camera so that you can actually watch the coin transition from a uniform cool temp to a uniform hot temp (or vice versa for that matter). The denser date area would reach the uniform high temp faster (probably milliseconds faster) than the adjacent areas of the coin. Watch the movie playback and you'd see the date appear then get washed out.

All for a $0.50 nickel.

 

I thought NSA spy satellites could read the date on a dateless nickel while still in your pocket?

Rob

 

Silver, Gold, Copper all form metallic bonds ( as opposed to ionic, covalent, etc.) and seem to resist efforts of x-ray diffraction ( although I haven't reviewed the literature on that lately). Since metallic bonding seems to be best described by quantum mechanics action of the electrons, I don't think that one could assume the atoms and their electrons as being fixed in location.

 

Use plain old household white vinegar, it's cheaper.