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Cerulean
Penny Hoarding Member
USA
993 Posts |
 Posted - 02/23/2007 : 08:08:11
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quote:
Not to stray off the thread, but I did read in a boat building book that zinc blocks are used as a sacrificial metal to protect bronze parts of a boat.
The zinc gets eaten away by seawater first before the bronze parts do, saving the expense or replacing bronze parts of a boat.
As a professional ship designer, I can attest to this. However, the reason is a little more complex. It's not just the bronze that is corroded; the presence of the steel hull near the bronze propeller creates a galvanic differential. When immersed in saltwater, this creates a BATTERY, leading to galvanic attack of the more reactive metal, bronze. Since zinc os more reactive than bronze, the galvanic attack eats away at the zinc instead. These anodes, about the size of a loaf of bread, must be replaced every few years.
Also, as I mentioned in another thread... CuNi alloys are used in piping for steam plants, as they are resistive to corrosion and high temperatures.
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Penny Search Totals:
881 zincs (1982-2006) 77.1%
254 coppers (1959-1982) 22.2%
6 wheats (1940-1952)
1 dime (2004)
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just carl
Penny Hoarding Member
USA
601 Posts |
Posted - 02/23/2007 : 20:01:51
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Posted - 02/22/2007 : 13:50:30
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Metalophile: I agree with the theory that the Zincolns turn to crud pretty fast. As I go thru sorting the copper out, I recently started setting aside the very few zinc cents that appear flawless. Very few.
Carl: Do you have a handy dandy link as to which zinc cents we should scrutinize more?
Here are just some of the Cents people ignor but are worth a lot and will be worth even more soon. 1983 Double struck on the reverse $200. 1992D with a close AM for $500. 1995 Double Die for $50 to $100. Remember that in 1982 there are at least 8 different Cents, large dates and small dates. The Zinc, Copper coated 1982 small date in Mint State condition is now going or about $4 but will be going up as soon as people continue thier distruction of these coins. These light weight, soft Cents bend, break, dent, smash, etc so easily they are well domed for long term usage making some of the more valuable ones even more valuable in the future. The introduction of the state quarters and the new dollar coins have made the estimated amount of coin colletors in the USA now up to 160 mllion. In many cases that means 1 of some coins per 160 people.
Carl |
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2007 Penny is All over the Place
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