DIG THOSE ZINC SIGNALS IF YOU WANT TO FIND INDIANS!

[coinman123]

I try not to dig any zinc signals, but today I found something out. I was testing different coins to see what the show up with on my metal detector and discovered that all small cents that are from before 1943 will show up as zinc pennys. It all depends on where you are, so if you are at a 1980s school you don't need the dig them. I hope I helped you guys.

Good luck,

 

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[OutdoorAdv]

So does anyone know why this is?

I am thinking that the IH's and early wheat cents were a different alloy than the later year wheat cents and pre 82 Lincolns.

Brass - alloy of copper and zinc
Bronze - alloy of copper and tin

The United States Mint · About The Mint says they're all "Bronze" ... "The cent was again bronze (95 percent copper, and five percent tin and zinc) from 1864 to 1962." (That says tin AND zinc) In 1962, the cent's tin content, which was quite small, was removed. That made the metal composition of the cent 95 percent copper and 5 percent zinc. The alloy remained 95 percent copper and 5 percent zinc until 1982

Wikipedia has the same info.
IH: (1864–1909) 95% copper, 5% tin or zinc (This says tin OR zinc... which means they are either brass or bronze)
Lincoln: 1909–1942, 1944–1982: 95% copper, 5% tin or zinc (This says tin OR zinc... which means they are either brass or bronze)

The later year Indian Heads and early year wheat's seem to register similar on all our machines. The later year wheats come in much higher. I'm thinking that the composition changed from a more Brass alloy to a more Bronze alloy, however all the information seems to just say "5% tin or zinc". There must be a year where they switched from 5% zinc to 5% tin or something and just never specified it... and thats why our machines register the earlier ones so different.

Not that this matters, since I dig everything, but I like to try and guess based on the sound and VDI what it is before I dig... it also helps me to get to know my machine better!

 

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[mreese1849]

I had an explorer se and indians were almost exactly like zinc penny's as well

 

[Slingshot]

On my BH 202 and my old TEK 9000B IHP's, minie balls, and zinc cents all read 40 or lower depending on depth and halo. Some IHP's have been just 2 inches down, but have found several minie balls right on the surface. I dig any clean coin sound, but as a day wears on the discriminator goes higher as I tire out.

 

[Nugs Bunny]

It's best to dig every target that you can for several reasons. I have a 115 year old house located next to an abandoned iron mine, there are targets, on top of targets, on top of targets and the ground is highly mineralized. What I have learned is there are many factors that can affect my machines readings, depth, position, condition, relation to other targets and ground mineralization all have an effect.

In front of my house is a brick sidewalk buried under a few inches of dirt. A penny was wedged in between two bricks and had a very strong signal but not that of a penny. The readings were all over the place and my machine couldn't decide what I was about to unearth, it did however give a nice consistent solid tone confirming something was buried there. Anything that affects the conductivity can affect the readings. When there are several targets under the coil, at different depths or side by side I will get mixed or inconclusive readouts but I still get a nice solid tone.

In cleaner areas with low mineralization my machine sounds dead on, even when it's a pull tab 10" down, yeah I might hope it's a ring but White's already knows it isn't lol! There are exceptions, anything that is similar in conductivity and composition can be identified incorrectly.

Those old pennies are worth almost 2¢ for the copper content, $0.0192262 is the melt value for the 1909-1982 copper cent on December 19, 2014.

But some are worth far more to collectors 1909 - 1982 Copper Lincoln Cent Value - Coinflation

The Composition of the Cent.

The United States Mint · About The Mint

Following is a brief chronology of the metal composition of the cent coin (penny):
• The composition was pure copper from 1793 to 1837.
• From 1837 to 1857, the cent was made of bronze (95 percent copper, and five percent tin and zinc).
• From 1857, the cent was 88 percent copper and 12 percent nickel, giving the coin a whitish appearance.
• The cent was again bronze (95 percent copper, and five percent tin and zinc) from 1864 to 1962.
(Note: In 1943, the coin's composition was changed to zinc-coated steel. This change was only for the year 1943 and was due to the critical use of copper for the war effort. However, a limited number of copper pennies were minted that year. You can read more about the rare, collectible 1943 copper penny in "What's So Special about the 1943 Copper Penny.")
• In 1962, the cent's tin content, which was quite small, was removed. That made the metal composition of the cent 95 percent copper and 5 percent zinc.
• The alloy remained 95 percent copper and 5 percent zinc until 1982, when the composition was changed to 97.5 percent zinc and 2.5 percent copper (copper-plated zinc). Cents of both compositions appeared in that year.

 

[Jason in Enid]

The best guess I have formulated for the range of target VDIs is because of corrosion and coin wear. Coins worn thinner change the VDI some, as does corrosion. It seems that every time I dig a small cent with a funky response, it has always had very heavy corrosion.

Just my personal observations, YMMV.

 

[lookindown]

On my AT PRO...copper cents read 81...zincolns 76 and Indian Heads 72...like Jason said, corrosion will change those numbers.