phlogiston
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gold ring weight loss
Hi all,
I have been occasionally weighing a gold ring I wear continuesly to see how fast it would wear. Surprisingly, I found the rate of wear over the last 7
years has been almost perfectly linear, (correlation coefficient = 0.999984), with a rate of 30.9 ug a day (my balance measures to 10 ug resolution,
so I can see detect weight loss over a single day). At this rate, it'll be gone in 432 years.
I would have expected the wear to be mostly due to friction with doorhandles, sand, etc. etc., but apparently not so because I don't measure any
additional wear after such activities as digging in the sand with my hands.
So, any theories as to where my wedding ring is going?
-----
"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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BromicAcid
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Quantification of the Abrasive Wear of a Gold Wedding Ring
I remember reading this awhile back and your thread reminded me of this. According to the paper most of the metal is abraded by the skin.
[Edited on 8/19/2010 by BromicAcid]
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psychokinetic
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Your blacksmith has been cheating you out of your gold, sire.
“If Edison had a needle to find in a haystack, he would proceed at once with the diligence of the bee to examine straw after straw until he found
the object of his search.
I was a sorry witness of such doings, knowing that a little theory and calculation would have saved him ninety per cent of his labor.”
-Tesla
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hissingnoise
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| Quote: | | I have been occasionally weighing a gold ring I wear continuesly to see how fast it would wear? |
Yep! That certainly gets my vote for the most futile and pointless exercise ever undertaken. . .
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Wizzard
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Another reason (on top of not liking gold) my ring will be either tungsten or platinum 
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hissingnoise
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It's that piss-yellow colour? Iridium?
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phlogiston
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Bromic, thanks, that was a fun read ("rock concert (clapping hands)... 17mg") and answered my questions. I wouldn't have believed anyone had gone
through such great lengths to satisfy their curiosity regarding this. neutron activation...respect!
Good luck making a tungsten ring btw. Neither casting nor cutting will be easy.
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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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aonomus
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On the bright side, if you do a daily measurement, it means you will keep your fingers slim enough to remove the ring (instead of letting them get fat
and never being able to remove it or clean under it (ew)).
How many data points did you measure to come to your figures in the OP? What is your average daily work (desk, construction, water/marine), there are
lots of variables to think about.
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unionised
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We noted a similar loss of material from one of our check weights in the lab A 500mg Ta weight lost about 0.25 µg (IIRC) per day on average.
(Tantalum is pretty hard so the idea that a W or Pt ring is safe from wear is questionable).
We taught the bloke doing the check weighing not to scratch the surface of the weight and got some plastic tipped tweezers; the weight loss rate
dropped considerably.
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