So, how do you absolutely KNOW if it's iron or not?

[NealNoIN]

I've read that iron starts at around a 40 vdi but guys are finding stuff thats well below that not being iron. Is this right?
Is there a number where I'm sure it's iron?
I'm not talking about the big iron that pushes the numbers way up to the coin zone. I'm talking about a coin size signal.
If depth and iron and minerals bring the numbers down then how will I ever know for sure?
Neal

 

[jmaryt]

generally a nice "smooth" hit will tip ya off! iron just sounds different,but CAN mimic non-ferrous.
depends on size,shape,and exact composition of the object detected!.also,if the target has appreciable depth to it,then "all bets are off the table!"
THAT signal SHOULD be dug,regardless!

(h.h.!)
j.t.

 

[NealNoIN]

n/t

 

[NealNoIN]

I just want it to tell me when one of the millions of small, possibly deep whispers is not iron. There is no way I'm going to dig all those pieces of iron.
I understand big iron raising the VID # but I just want a way to be sure that if it's a 20 or 30 or 35 and it's a very small profile of a signal, it is iron.

 

[ExpIInut]

Hi - I was a bit like you in thinking that I may be missing something with a higher discrim - I hunt with the discrim set at 39, and whilst out the other day I set off from the car with the discrim set at 1 - yes that's #1 - assuming that any target between 1 and the supposed cut off point for iron (40) would give a nice solid repeatable signal - WRONG - above 40 fine but below? try it!

I've also seen a statement about setting the discrim above 50 gives more depth - you hunt in front of me set at 50 I'll follow behind at 39 and pick up what you leave

 

[dirt lizard]

I've heard some people say they pulled gold rings at 48 but they were small. What i do is take notes on what I dig up on lower numbers and adjust my disc accordingly. But i usually keep it at 50

 

[NealNoIN]

n/t

 

[NealNoIN]

n/t

 

[ExpIInut]

n/t

there's a link to a chart someone did with the G2 I'll try and find it

 

[Monte]

we tend to find the old iron trash at most of the pretty good past-era sites. We have come a long way through the years with detector design but there still isn't, and never will be, a 'perfect' detector. Teknetics & Fisher do offer us some pretty good units, if we can match what they can do with the needs we have, and that includes using the Gold Bug Pro or G2 in trash-infested sites. I use my G2 w/5" DD for many of them, and it does reasonably well and I recover very little iron junk.

I've read that iron starts at around a 40 vdi but guys are finding stuff thats well below that not being iron. Is this right?

MOST iron-based targets will fall in the 0-40 Discriminate VDI range. Not all. MOST non-iron targets will read with a VDI higher than '40'. I have found targets, small gold earrings and such, that have responded with a less-than-'40' VDI on the G2, and Gamma and Omega. Were they iron? No, but they were very low-reading and, due to the composite of the ground signal and target signal there was a lower-reading VDI.

I have a lot of iron nails and they all read under '40'. I also have two old rusty "church keys" used to pop the caps off the soda bottles long ago and they also respond with an "Iron" VDI and audio. But not all the time. If they are positioned as-if "on edge", they respond like the iron nails and other similar-shaped ferrous targets. Then, if they are turned as if they were laying on the ground so as to see the open shape that is all connected in the odd shape of the opener, they respond with a much higher-than-'40' VDI, and respond well.

You can adjust the Discrimination, OF ANY DETECTOR, to reject all common "iron" and the church keys will still respond. Why? Because even though they are an iron-based object, they also have a man-made shape (a more conductive closed-end loop) that adds to their conductivity and there's nothing you can do about that. They are going to 'beep!'

So, there will be times when some iron will respond above any detector's iron-range rejection point. There will also be times when some smaller, lower-conductive targets located in bad ground will read a bit lower into an iron range.

Is there a number where I'm sure it's iron?

No. There is a number when MOST iron will respond at or below the '40' VDI on the G2/Gold Bug Pro, and as long as the iron object is shaped in a form that is NOT very conductive (as if more than where most typical iron responds), then it's likely to be iron.

I'm not talking about the big iron that pushes the numbers way up to the coin zone. I'm talking about a coin size signal.

It's not just large iron that has higher conductive properties, but those that are simply shaped so as to have more conductive properties. It's easy to note this if you have a simple paper clip. Note that it will cling to a magnet.

Open it up into a 'U' shape and move it past the search coil as if it were laying on the ground and you'll get a 'proper' low Iiron reading and lower audio Tone ID (if set for Iron (below 40 on the G2/Gold Bug Pro) audio response. You can see and hear that one piece of "iron" responds as if it was "iron."

Now, just bend it around a little bit more so that you pinch the two ends together and make contact to form an 'O' shape. Now, move it past the search coil in the same laying-flat position and not the response. Ooops! It's not iron-like anymore. Target shape can add to, or detract from, a target's conductivity level. A nice gold ring reads up-scale pretty well, but if you cut through the band and move the two ends just slightly apart, the response is much, much lower. Same gold material, but you altered the conductive properties of the object.

If depth and iron and minerals bring the numbers down then how will I ever know for sure?

You can use some techniques to try and classify some potential iron targets, such as the 'EPR' and 'Quick-Out' techniques I have used since about '79 and instructed in seminars for 30 years now. (You can find them under Tips & Techniques listed as Audio Target Classification (ATC) at www.ahrps.org and print them out.)

I use audio classification a lot, and with good success, but I also know that due to so many variables I might be wrong just as a detector might be wrong. The only way to confirm a located target's identity is to recover it and take a look.

I hate to sound so negative but it sounds like the G2 is useless as far as ID ing the good stuff (deepies).

Deeper targets are going to be very difficult to identify for any detector. You can have the issues of the target metal make-up, the deterioration of those targets over time due to acids and other chemicals associated with some ground minerals, plus they might be in an odd position or maybe they are of an odd shape.

I own and use several detectors and of them all, the G2 tends to produce a rather reliable VDI read-out to a greater percentage of its overall depth capability. It might not be the deepest-detecting model on higher-conductive coins (silver or copper), and I have others than can detect most coins a little deeper, but the G2 does give a close-to-accurate VDI on a greater percentage of its overall depth capability.

I just want it to tell me when one of the millions of small, possibly deep whispers is not iron. There is no way I'm going to dig all those pieces of iron.

Sadly, a "whisper" is not easy for the detector to hear and make an accurate conclusion. Heck, I have a tough time hearing a "whisper" myself. I will say that overall the G2 with the 5" DD coil does a pretty decent job in classifying most targets in a typically trashy site.

I understand big iron raising the VID # but I just want a way to be sure that if it's a 20 or 30 or 35 and it's a very small profile of a signal, it is iron.

No guarantee, but generally most lower-reading VDI's in the iron range will be iron.

We had a power outage and I lost Internet or I would have responded in a more timely manner. Now, I have about an hour until daybreak and the G2 is in my rig and ready for some early detecting before it gets hot. All the best to you.

Monte

 

[Monte]

I've also seen a statement about setting the discrim above 50 gives more depth

I found that to be true with the Teknetics T2. it's all a matter of how the detector was designed and with the T2, an increased Disc. setting of about '50' can give you a little more zip.

Monte

 

[Dave J.]

The only way to know for sure what a target is, is to dig it. And even with it in your hand, sometimes you may not be sure. If you carry a magnet (like most gold prospectors do), that will provide nearly 100% accurate ferrous-nonferrous discrimination for targets already dug.

The metal detector doesn't know anything specific about metals or for that matter even dirt. All the machine "knows" is that it's seeing wobbles in a reactive signal and other wobbles in a resistive signal. The machine then takes a guess as to what most likely caused that pattern of wobbles. In the case of buried targets, the machine is seeing both ground and the target, and has no certain way to distinguish between the two. It's all guesses. The engineering of metal detectors is mostly a matter of designing the machine to make smarter guesses.

Knowing how to use the machine properly will also help the machine to make smarter guesses. But in the end, the decision of whether or not to dig is a guess made by the person swinging the beeper.

--Dave J.