Idea For Creating Test Nuggets Of Various Sizes?

[roddosnow]

So by what steelphase and Goldilocks have said does that mean that using aluminium as a test piece for a vlf detector(gm100/equinox/gmt etc) would be closer to gold than using lead test pieces as the vlf uses conductivity rather than decay rate to assess targets?

 

[madtuna]

I just test on undug targets.

I don't care how my detector works...just how to work it

 

[EVIE/BEE]

steelPHASE,
Lead oxide will mask the response slightly, make sure the lead is shiny bright. Thats on a PI detector.. don't know about VLF.

 

[SteelPat]

steelPHASE,
Lead oxide will mask the response slightly, make sure the lead is shiny bright. Thats on a PI detector.. don't know about VLF.

For general testing, the oxidisation will have no markable effect unless its a very small piece of lead or the oxidisation is severe.

(Just realised this profile is still active as well as steelPHASE :| )

 

[SteelPat]

So by what steelphase and Goldilocks have said does that mean that using aluminium as a test piece for a vlf detector(gm100/equinox/gmt etc) would be closer to gold than using lead test pieces as the vlf uses conductivity rather than decay rate to assess targets?

On a VLF aluminium seems to produce similar numbers to gold - this certainly bears out when I'm using the Equinox.

 

[Redfin]

FFS people, stop over thinking and evaluating.
Most machines in factory presets will perform well, IF YOU WALK OVER IT

 

[condor22]

FYI

Gold leaf is manufactured to standard European size of 80 x 80 mm (3.15 x 3.15 inches) with a weight of 14-15 grams per 1000 leaves,
or 1.5gr /100 sheets = 0.015gr each sheet.

A booklet contains 25 leaves = 0.375gr and costs $50 which works out at $133/gr (and it's 21 ct)

It also needs the item to be covered to have adhesive applied for it to be removed from the transfer paper.



Still think it's a good idea, lol

 

[SteelPat]

FFS people, stop over thinking and evaluating.
Most machines in factory presets will perform well, IF YOU WALK OVER IT

So true. A guy with a CTX3030 picked up a nice 4oz bit after the Wedderburn token hunt.

 

[ironrock]

Hey Condor, when i first posted this idea, i had never actually held a piece of gold leaf in my hand, i ended up buying some, and then realised just how thin this stuff really is, i somehow imagined it to be the thickness of aluminium foil, boy did i get a shock, so no, it is not even close to being a good idea, but thanks for taking the p***!!!!

 

[Candigger]

resurrecting an old thread here, but the other day whilst reading through the Nexus Detectors website & watching their videos, somewhere I came across a mention of guys making their own test nuggets from an alloy of 60%Tin & 40%Lead.
This made me take notice as I have a supply of pure tin from my shooting days making my own special alloys & casting my own projectiles.
Now from reading some of the comments in this thread, & the fact that detectors generate eddy currents in a metal object that then generates its own micro electro-magnetic fields, that the detector then detects (& its decay), it seems that making this alloy is pointless as lead & tin are similar electrically, but a bit different from gold. If the signal from gold vs lead is nearly the same, then using a lead/tin alloy would seem to make very little to no difference at all.
Has anyone here ever tried this 60/40 alloy?
Any results or comments on what was achieved?

60/40% Tin- Lead alloy is a standard solder wire for electronic components sold in all electronics shops. What was used in the Nexus videos is probably fall out from manufacturing process.
Pure Tin could be a better choice as it is more conductive than Lead and with similar weight.

 

[user 4386]

Cant say it was exact as I am not going to muck about with my gold nuggets but it was very close. But I have compared decay rates on an oscilloscope between lead and gold and they are different - the decay rate is more or less independent of nugget shape/size and is more about the chemical composition of the element. As PI machines look at the decay rate, it stands to reason that there will be a difference. As I mentioned before, it will depend on the quality and design of the receive circuitry as to whether that difference is able to be perceived on a particular machine.

Does anyone know what property of the metal it is that determines its decay rate? The only geophysical method that I am familiar with that uses decay rate is Induced Polarisation, in which one puts a current flow into the ground and any conducting grans polarise, with a positive charge on one side and a negative charge on the other (oriented with the same polarity on all grains. When you switch off the current the polarisation collapses (seen as a voltage decay between two electrodes), and the rate of collapse depends on the amount of the conductor present. Obviously not the same technique (eg no voltage put into the ground between electrodes), but is their any similarity in the property being measured?

 

[steelPHASE]

Does anyone know what property of the metal it is that determines its decay rate? The only geophysical method that I am familiar with that uses decay rate is Induced Polarisation, in which one puts a current flow into the ground and any conducting grans polarise, with a positive charge on one side and a negative charge on the other (oriented with the same polarity on all grains. When you switch off the current the polarisation collapses (seen as a voltage decay between two electrodes), and the rate of collapse depends on the amount of the conductor present. Obviously not the same technique (eg no voltage put into the ground between electrodes), but is their any similarity in the property being measured?

Ok so in basic terms the coil on a PI detector is switched on and off very fast. When its turned off the magnetic field collapses in a fast transient dB/dt. This magnetic transient induces eddy currents in a metal target. From the sudden collapse, the induced eddy currents decay exponentially, with a time constant determined by the characteristics of the target. The decay of these induced eddy currents within a target is what we are looking at. Unfortunately the characteristics of the target are not the same, even for a given material ie gold. The characteristics can vary depending on size, shape, density etc and as we know gold nuggets vary widely from solid lumps to speccies to reef gold etc etc. This is one of the reasons that discrimination is so difficult on a PI machine.

Hopefully that makes it a little clearer.

regards Pat

 

[Magilla]

Does anyone know what property of the metal it is that determines its decay rate? The only geophysical method that I am familiar with that uses decay rate is Induced Polarisation, in which one puts a current flow into the ground and any conducting grans polarise, with a positive charge on one side and a negative charge on the other (oriented with the same polarity on all grains. When you switch off the current the polarisation collapses (seen as a voltage decay between two electrodes), and the rate of collapse depends on the amount of the conductor present. Obviously not the same technique (eg no voltage put into the ground between electrodes), but is their any similarity in the property being measured?

Ok so in basic terms the coil on a PI detector is switched on and off very fast. When its turned off the magnetic field collapses in a fast transient dB/dt. This magnetic transient induces eddy currents in a metal target. From the sudden collapse, the induced eddy currents decay exponentially, with a time constant determined by the characteristics of the target. The decay of these induced eddy currents within a target is what we are looking at. Unfortunately the characteristics of the target are not the same, even for a given material ie gold. The characteristics can vary depending on size, shape, density etc and as we know gold nuggets vary widely from solid lumps to speccies to reef gold etc etc. This is one of the reasons that discrimination is so difficult on a PI machine.

Hopefully that makes it a little clearer.

regards Pat

Took the words right out of my mouth. LOL.

 

[user 4386]

Does anyone know what property of the metal it is that determines its decay rate? The only geophysical method that I am familiar with that uses decay rate is Induced Polarisation, in which one puts a current flow into the ground and any conducting grans polarise, with a positive charge on one side and a negative charge on the other (oriented with the same polarity on all grains. When you switch off the current the polarisation collapses (seen as a voltage decay between two electrodes), and the rate of collapse depends on the amount of the conductor present. Obviously not the same technique (eg no voltage put into the ground between electrodes), but is their any similarity in the property being measured?

Ok so in basic terms the coil on a PI detector is switched on and off very fast. When its turned off the magnetic field collapses in a fast transient dB/dt. This magnetic transient induces eddy currents in a metal target. From the sudden collapse, the induced eddy currents decay exponentially, with a time constant determined by the characteristics of the target. The decay of these induced eddy currents within a target is what we are looking at. Unfortunately the characteristics of the target are not the same, even for a given material ie gold. The characteristics can vary depending on size, shape, density etc and as we know gold nuggets vary widely from solid lumps to speccies to reef gold etc etc. This is one of the reasons that discrimination is so difficult on a PI machine.

Hopefully that makes it a little clearer.

regards Pat

Thanks Pat - yes it does.