Assorted links

by on July 15, 2012 at 4:10 pm in Uncategorized | Permalink

1 Mark Thorson July 15, 2012 at 4:22 pm

I’ve considered building a machine to automatically sort out silver dimes from the regular ones. When irradiated with a neutron source, silver is activated to a couple of short-lived radioisotopes which are easily detected. A solenoid can kick out the silver dimes into a separate bin.

2 Curt F. July 15, 2012 at 6:23 pm

Neutron source? Sounds hard. Wouldn’t it be easier to exploit the difference in density between siilver and copper somehow? Molten bismuth maybe?

3 Mark Thorson July 16, 2012 at 10:21 am

No, neutrons are easy. I did this as a physics lab exercise in college. The copper-clad coins have exactly the same mass as the silver coins, which is necessary so they work in the same coin-operated vending machines.

Vision systems are getting more affordable these days, It might make sense to use one of those to kick out the valuable coins. It could also hunt for valuable dates and mint errors.

4 Johnz July 16, 2012 at 12:40 pm

It probably wouldn’t be nearly as cool as using neutrons, but years ago I worked in a liquor store….silver coins make a distinctly different sound when dropped than other coins. We all got to be very good at noticing it. I wouldn’t imagine it would be particularly difficult to build a machine that could tell the difference.

5 Rahul July 16, 2012 at 5:38 pm

Copper and Silver have a 15% electrical conductivity difference. Ought to be able to exploit that too pretty easily.
Unless the alloying does something funky.

6 dearieme July 15, 2012 at 6:36 pm
7 liberalarts July 15, 2012 at 7:08 pm

As a 3rd through 6th grader, I spent many a Saturday morning in the 1970s biking to banks and sorting through change like this, though back then $.50 pieces were the best way to earn a buck. By 7th grade, my opportunity cost had risen to the point where it wasn’t worth the time, relative to mowing lawns and throwing papers. You never lose the eye, though. I can’t read a date on a dime anymore with my 46 year-old eyes, but I can still pull a silver coin out of my change by sight, and in fact found one in my change yesterday!

8 Jamie July 15, 2012 at 7:16 pm

I think that would suck, as a business model. Sorting different coinage is actually a solved problem. Consult your local vending machine for more information.

9 Brandon Berg July 15, 2012 at 8:42 pm

Huh. I have never found a silver coin in the wild, ever. I used to check every coin I got as a kid, and I’ve seen enough in collections that I’d be able to spot one by color, but I’ve never actually found one. I assumed they’d all been culled years ago.

10 liberalarts July 15, 2012 at 10:36 pm

@Brandon – I think that they have in most places now that silver has not been used since 1969 (half dollars only) and 1964 for most coins. But when I moved to my current town that is loaded with old people, I started finding them again occasionally. They are in drawers and jars, and eventually get spent down into circulation. In modern, growing areas there are no people who have lived in the same houses for 50 years.

11 NAME REDACTED July 16, 2012 at 8:01 am

Governments tend to debase currencies. How is what the man’s doing rent seeking? He’s preforming a useful service. He’s increasing the supply of a more valuable good (silver) and decreasing the supply of a less valuable good (dimes).

Also, its funny to see a modern example of literal currency debasing. We read about the Romans doing this in the history texts and they are always chided.

12 brostiat July 16, 2012 at 12:22 pm

#1: high-end chef buddy says that burger is about $50 at cost

13 careless July 16, 2012 at 8:59 pm

I do not think he can buy 3 $100 bills for $50

14 careless July 16, 2012 at 9:01 pm

But if he can, I have a lot of money to invest in this.

15 Pearl Y July 16, 2012 at 10:19 pm

The burger is lame but the concept of “champagne steam” made me smile.

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