Standardized Tests for Metal Detectors

[WM6]

"...we need standardized testing soil surrogate..."

Well... i tend to agree on this... but also to disagree too.
What's the point if we take only one or two cases of soil surrogate? What's the goal?
We must know that various detectors do perform different on various soils, on some are better performing and on some worse.

There is nothing like ideal test.
Every test is some sort of compromise.
I know that my test, does not suit ideal to all terrain condition.

Personally, I'm not willing to make compromise, which would nullify the two (above mentioned), basic postulate.
If I could be able to test all existing detectors at once, then I will perform some sort of ground test and perform test for all detectors at the same day in same conditions.
Cause I am not, I need to chose test that guarantee the same testing condition to all tested detectors, no matter if tested today or 3 years later.

Compromising "same testing condition" postulate, I would not believe in my tests anymore, and all efforts become nonsense.

I checked many other testing ideas and approach before I decided to make test on standardized testing substrate (which are equal to highly |but not extreme| mineralized soil).

This is what I can do in my amateur conditions.

At the end, with different testing approach, we can get better interpolate picture of different detectors capability.

[ivconic]

There is nothing like ideal test.
Every test is some sort of compromise.
I know that my test, does not suit ideal to all terrain condition.

Personally, I'm not willing to make compromise, which would nullify the two (above mentioned), basic postulate.
If I could be able to test all existing detectors at once, then I will perform some sort of ground test and perform test for all detectors at the same day in same conditions.
Cause I am not, I need to chose test that guarantee the same testing condition to all tested detectors, no matter if tested today or 3 years later.

Compromising "same testing condition" postulate, I would not believe in my tests anymore, and all efforts become nonsense.

I checked many other testing ideas and approach before I decided to make test on standardized testing substrate (which are equal to highly |but not extreme| mineralized soil).

This is what I can do in my amateur conditions.

At the end, with different testing approach, we can get better interpolate picture of different detectors capability.

Perfectly makes sense.
We definitely should add your method to "Geotech md testing standards".
Referring to previous Nexus's remark; air tests, yes those are not meritorious much too, but air tests should also be added to "Geotech md testing standards".
Air test can tell us much, if performed correctly.
Youtube link provided by Qiaozhi in first post of this topic is showing us very important thing.
And it belongs also under "air test" category.
So i am proposing all the tests to be done in 3 (so far) stages:
1) Air test (same setup as on video above)
2) WM6 test (soil substitution reference)
3) Real soil testing series (more complex than first two)

[ivconic]

We can also take in consideration John Lynn's testing methods too.
So far he was the only one maintained and did it uniformly for longer period.

[Nupi]

...................
Youtube link provided by Qiaozhi in first post of this topic is showing us very important thing.
And it belongs also under "air test" category.
.............................

Pity that the same test is not done in the ground. Had then important data delivered.
The important question for me is: Deus also could detect the coin in the ground? and the rest of the MD not?
Or maybe we had seen a big surprise?

[ivconic]

Pity that the same test is not done in the ground. Had then important data delivered.
The important question for me is: Deus also could detect the coin in the ground? and the rest of the MD not?
Or maybe we had seen a big surprise?

You also followed the other topic too, in Off Topic part of this forum, right?
Have you read my post there where i suggested the similar setup? (Qiaozhi obviously did read and understood it well!)
Take a wild guess; why i suggested such similar setup?
Because i knew the results, that's why!
And that's why i do respect Deus that much.
I hope i answered your question.

[Davor]

There is nothing like ideal test.
Every test is some sort of compromise.
I know that my test, does not suit ideal to all terrain condition...

True. However, can you imagine someone in Hawaii obtaining a mineral-deprived soil to test a detector in European conditions, while everything around him is a volcanic soil that makes detectors crazy? I'd say every synthetic test, provided it is cheap enough, will do well.
So far I like your solution very much.
I'm still not at terms what would make a good target. I guess some electronic components are made in some kind of bronze. I know most of them are made with/of stainless steel, but perhaps there are some that use some different alloy, and are cheap to buy. Those have tight tolerances, so why not.
I have a completely different idea as well. How about melting a blob of, say, 7g solder, and using it as a target? There are but a few slightly different solder recipes, and 60/40 Tin/lead (Sn/Pb) which melts at 188 °C is the most common. Perhaps someone may suggest a good way of casting it into a preferred shape, clay or something, but material-wise this seem pretty consistent, cheap, and widely available.

[Nupi]

You also followed the other topic too, in Off Topic part of this forum, right?
Have you read my post there where i suggested the similar setup? (Qiaozhi obviously did read and understood it well!)
Take a wild guess; why i suggested such similar setup?
Because i knew the results, that's why!
And that's why i do respect Deus that much.
I hope i answered your question.

I have some questions? Maybe you can help me, because you have done the test itself.

Do you know the height between of the nails to the coin?

Do you know the distance between the coin and the nails?

thanks.

[WM6]

I know most of them are made with/of stainless steel, but perhaps there are some that use some different alloy, and are cheap to buy. Those have tight tolerances, so why not.

This sort of metal (specifically: hypodermic needless) is most intrigues to me couple of years. Many school and kindergarten here expressed big interest to clean their yards from this dangerous thigs hidden in grass and repeatedly ask which detector is capable to clean it. I am not able to help with advice: till yet, no one of tested detectors from Deus to ATX was not able to detect stainless steel hypodermic needless. For now the only real solution I can see, is to add some sort of copper ring to needle connecting part during production (hope this will be some producer patent idea) or make silver plated needle (silver has at the same time antibiotic properties).

And yes, testing sample discussion is interesting field here, regarding alloy, shape, mass, surface structure, phase changing, time constant etc.

One remark regarding air test. We need to consider applied technology. No motion detectors suit better (more real) to air tests. On other side motion designs need to be ground balanced to perform more real results.

[Nupi]

This sort of metal (specifically: hypodermic needless) is most intrigues to me couple of years. Many school and kindergarten here expressed big interest to clean their yards from this dangerous thigs hidden in grass and repeatedly ask which detector is capable to clean it. I am not able to help with advice: till yet, no one of tested detectors from Deus to ATX was not able to detect stainless steel hypodermic needless. For now the only real solution I can see, is to add some sort of copper ring to needle connecting part during production (hope this will be some producer patent idea) .........

I did some testing with needles and have some successes, I wanted to talk about it with people,
but there is no interest at the Forum.

[ivconic]

I have some questions? Maybe you can help me, because you have done the test itself.

Do you know the height between of the nails to the coin?

Do you know the distance between the coin and the nails?

thanks.

I didn't done no test at all, you misunderstanding my point.
I knew the results because i was so many times in such situation on REAL SOIL with REAL TARGETS and with several metal detector models so far.
I have 8 Roman/Byzant sites around my home, in radius up to 12km.
All of those are as explained; heavily infested with small iron particles, rusty junk and minerals on first 5-10cm detph.
Under that layer there is a second layer, 10-40cm depth where occasional precious finds may be discovered.
Usual finds (in last time with Deus ONLY) which i am having are bronze and silver coins with diameters from 4mm to 15mm.
The same 8 sites i've been visiting regularly in last 27 years (several times per year am visiting each of those).
I took there with me all the md models i had so far (92 various models since 1987.)
And that's what is the "source" of all my experiences i often do share here.
Hopefully you understand now?

[ivconic]

I did some testing with needles and have some successes, I wanted to talk about it with people,
but there is no interest at the Forum.

I am truly interested to hear your impressions.
Because in recent past WM6, Tinkerer and me also experimented with needles too.
Please share your experiences here on this topic, because it correlate closely to testing subject.

[WM6]

I am truly interested to hear your impressions.
Because in recent past WM6, Tinkerer and me also experimented with needles too.
Please share your experiences here on this topic, because it correlate closely to testing subject.

Yes, I haven't significant results for practical use. Even detector, that can detect my bare hand mowing in front of coil, was not able to detect hypodermic needles. Maybe nupi has needle made out of different alloy, I don't know. Namely hand-sewing needle in the same weight and shape, as comparable hypodermic, can be easily detected.


Here some variation on test approach and interesting results too:

http://www.staffsmetaldetectors.co.uk/iron_test.htm

http://www.staffsmetaldetectors.co.u..._halfpenny.htm

http://www.staffsmetaldetectors.co.uk/5_pence.htm

http://www.staffsmetaldetectors.co.u...ered_penny.htm

[Nupi]

I am truly interested to hear your impressions.
Because in recent past WM6, Tinkerer and me also experimented with needles too.
Please share your experiences here on this topic, because it correlate closely to testing subject.

I do not want to debunk the Deus or boast about my MD. But the test of the video I also done now itself.

The height between of the nails to the coin was 6 cm
The distance between the coin and the nails On both sides of the coin 5 cm.
The target coin was thin gold pendant from 2 cm, 1 euro, quarter and 50 euro cent.No problem to detect.

hypodermic needless tests in Dutch air: horizontal------diagonal-------vertical
With disc on and reject rusty nail.

Terumo 26G = 0,45 x 12 mm -------------- 6cm------------4cm-----------2cm
Terumo 25G = 0,5 x 25 mm --------------- 7cm------------5cm-----------2cm
NovoFine 31G = 0,23/0,25 x 6 mm ---------3cm ------------2cm --------0,5cm

[Nupi]

Yes, I haven't significant results for practical use. Even detector, that can detect my bare hand mowing in front of coil, was not able to detect hypodermic needles. Maybe nupi has needle made out of different alloy, I don't know. Namely hand-sewing needle in the same weight and shape, as comparable hypodermic, can be easily detected.


Here some variation on test approach and interesting results too:

http://www.staffsmetaldetectors.co.uk/iron_test.htm

http://www.staffsmetaldetectors.co.u..._halfpenny.htm

http://www.staffsmetaldetectors.co.uk/5_pence.htm

http://www.staffsmetaldetectors.co.u...ered_penny.htm

Are you angry at me?

[Qiaozhi]

True. However, can you imagine someone in Hawaii obtaining a mineral-deprived soil to test a detector in European conditions, while everything around him is a volcanic soil that makes detectors crazy? I'd say every synthetic test, provided it is cheap enough, will do well.

Due to widely varying soil conditions around the world, we should probably focus on "synthetic Tests" (as referred to by Davor). These sort of tests can be performed anywhere; such as the wood, nails and coin example. The problem comes with emulating different soil conditions. For example, heavily mineralized soil could be emulated using several toroidal ferrite cores glued to a board. We could devise many such "synthetic" tests, not just for comparing commercial detectors, but also for testing our own designs.
One potential "synthetic" test, that no-one has mentioned, is for wet salty sand. Or even better, the interface between wet and dry sand.