One dollar gold piece replacement ?

What would be wrong using a corroded V nickel? In my ground most of them that I have found read as high foil, just below the nickel range with a good target ID machine. I have a buffalo nickel in my test garden that I buried 15 years ago next to a lot of rusty nails, in one direction of sweep it up scales the meter reading to the pull tab range, then in another direction of sweep it reads as a normal nickel would. So when iron nails are in the mix, they will either pull them down the scale or upscale to a higher reading on a meter. Therefore the test would be invalid when iron gets in the way, I can deal with nails, it is the aluminum trash that drives me bats.

What we have here is a failure to communicate.

Past(or)Tom
Using a Legend, a Deus 2, an Equinox 800, a Tarsacci MDT 8000, & a few others...
with my beloved, fading Corgi, Sadie

[www.nde-ed.org]


Since we are dealing with induced eddy currents on the surface of the coin, how expensive or difficult would it be to simply electro-plate a metallic slug with the appropriate karat gold coating , all things equal except for the exact stampings ?



Edited 1 time(s). Last edit at 07/10/2014 10:00AM by Tri.

I acquired some fake or replica California fractional gold dollars many years ago just for such testing which, if memory serves, sounded off much like a $1 gold dollar. I don't know what they were made of, but were gold plating and served the purpose. There must be some of them still available out there for interested buyers. One was a round $1 and another was an octagon shape. I have no idea where mine are today, but I'd try flea bay and see if someone still has them for sale. They might serve the purpose.

Quote:"how difficult would it be to electro-plate a metallic slug with the appropriate karat gold coating"
Unfortunately, very difficult. Plating Pure 24K gold is easy, alloys are near-impossible, as one element or the other will plate out first. Switch / relay manufacturers have techniques that allow gold alloys to be deposited on switching contacts, to get the right combination of wear-resistance, corrosion-resistance, wetting current etc etc. But these are very small deposits, and may be made by some other process like sputtering. This info was obtained from the website of relay-maker Deringer-Ney.



Edited 1 time(s). Last edit at 07/10/2014 12:19PM by Pimento.

All are well stated.
..............................

Although lead does indeed have a different density as compared to gold.......... you could make a Type-1 gold coin out of lead...... and I believe this would 'more closely' emulate a $1.00 gold coin.

My research showed that lead was too far away from 90/10 Au/Cu alloy in specs to be useful (almost a factor of 2 different, actually). But data I found on low-melting-point alloys yielded a very close match, #160 alloy lead-free solder.
I've now found my notes, and the other data I'm sure I have archived (recovered from a hard-drive that head-crashed badly), so I'll attempt to add it to the replica dollar thread later today.
Edit : now updated.



Edited 3 time(s). Last edit at 07/10/2014 02:19PM by Pimento.

Pimento have you tried gold leaf as standard 22 k gold leaf is awful close to the 21.6 k or 90 % Au/Cu alloy ?

Skin depth would typically be 0.2mm, so I imagine that any surface plating/coating would ideally be this sort of thickness. These figures are purely from memory, it's frequency dependant, of course. Gold leaf is always very thin, so I'm not optimistic about it's suitability.

Though I dislike the idea of a gold coin as a test target, I though it worth pointing out that there are modern fractional-ounce coins out there, but it seems most (or all) are 0.999 fine gold, not 0.900 or 22 carat, so will ID significantly differently, making them unsuitable.
We have a quarter Sovereign here in the U.K, weight is 2.00 gram of 22 carat (0.916) gold. That wouldn't be a bad choice.



Edited 3 time(s). Last edit at 07/13/2014 10:21AM by Pimento.

Two words... Alchemy.

Past(or)Tom
Using a Legend, a Deus 2, an Equinox 800, a Tarsacci MDT 8000, & a few others...
with my beloved, fading Corgi, Sadie