Shocking results with Sigma Major failure

[James32]

29 minutes ago, Petra said:

So, is this bar getting chopped or something to see what’s inside?

Most likely a brass core

[paulmerton]

80% silver coins with a balance of copper are also quite close to gold in terms of resistivity.

[Spyder]

4 minutes ago, James32 said:

Most likely a brass core

I would agree with brass as the sigma did not pick up copper with the copper setting

[Roy]

Couldn't sleep....🛌

@Spyder 's spidey senses got me paranoid 😂

I can't explain the extra 1% though 🤷‍♂️

[James32]

8 minutes ago, Roy said:

Couldn't sleep....🛌

@Spyder 's spidey senses got me paranoid 😂

I can't explain the extra 1% though 🤷‍♂️

I remember reading that on breakable combi bars, they are not required to weigh 1g exactly, but the whole Combi bar must weigh the stated weight as a minimum ( whether 50g or 100g) that was a dealers response to a member of here that was a little shy of a gram 🤣

[paulmerton]

Just now, James32 said:

I remember reading that on breakable combi bars, they are not required to weigh 1g exactly, but the whole Combi bar must weigh the stated weight as a minimum ( whether 50g or 100g) that was a dealers response to a member of here that was a little shy of a gram 🤣

Most combibars are about a gram overweight in total to reduce the likelihood of individual pieces being underweight.

[NGMD]

My paranoia also kicked in like @Roy today. 
I received 9 PAMP in Assay (1g-5g)bars today and went about my amateur testing routine. Bars weighed within parameters in Assay, looked good, Sigma tested after pushing the small probe in the plastic (no puns) and measured. I went to use PAMP’veriscan and all failed to register. Squeaky bum time. I then downloaded another App and that just froze when rotating the camera to measure ‘Fortuna’. 
‘Oh Balloon Knots’, what next? Then I saw you can scan the QR code on the IPhone and it directs you straight to PAMP with the downloadable certificate/serial number. Turned that frown upside down. 
Just in case anyone has this problem.

[Aldebaran]

On 12/06/2023 at 21:51, Spyder said:

Went today see a local person who was interested in purchasing a couple of sovereign. Well I took my Sigma with me to prove that they were genuine. Cut a long story short He had this gold bar which he had bought on eBay. He was suspicious and open the blister pack and it was quite shocking. We ran some test. The result were not good. Luckily for him he got his money back from the seller. Anyway he gave me this bar. I ran plenty of tests when I got back. 

This is why I do not buy Gold bars. I would advice those who have bars in blister pack to open and run proper tests. This was Perth mint fake bar. These fake bars are getting better. How would you know your bar is underweight if you do not take out of the tamper proof blister pack.  See my results. I am disappointed with the sigma.

Spyder

Oh Spyder, this is awful.

Like you, we have never had any interest in bars, but can understand why people like them and why this may cause disquiet.

Having said that, I have ordered a Sigma it will be another stage of verification.

Thank you for bringing this to everyone’s attention.

[Spyder]

2 minutes ago, Aldebaran said:

Oh Spyder, this is awful.

Like you, we have never had any interest in bars, but can understand why people like them and why this may cause disquiet.

Having said that, I have ordered a Sigma it will be another stage of verification.

Thank you for bringing this to everyone’s attention.

I would say the sigma is good on certain things, but not fool proof.  To be honest I was a little embarrassed when I tested the fake in the original owner's presence. We both knew it was fake and when it registered in the brackets straight away while in the blister pack. It was only while using the wands after removing from pack, the test picked up that it was not real. 

Like I said, most people would never remove from the pack and this is what these scammers depend on to get away with it. This person had payed £500 for it. Luckily he got his money back. The scammer wanted the bar back, but he told them, that it is illegal to post fake stuff through the post and so the scammer refunded his money and now I have it.

[JohnA1]

Wow, just saw this thread.

I haven't got this version of PMV, but I think that none of the readings appearing here are valid - because the cursor is not black.

I suspect that the difference in the cursor colour is the instrument warning that the reading is not correct.

Now if the cursor were black and between the brackets, then you'd have reason to question the accuracy, as long as the setting were on the correct coin type (yet another gotcha!)

Even then, the PMV Original only checks for plating, it doesn't check through the whole of the coin. Only the PMV Pro does that, along with specific gravity testing.

 

Edited July 17, 2023 by JohnA1

[paulmerton]

15 minutes ago, JohnA1 said:

I haven't got this version of PMV, but I think that none of the readings appearing here are valid - because the cursor is not black.

I suspect that the difference in the cursor colour is the instrument warning that the reading is not correct.

Now if the cursor were black and between the brackets, then you'd have reason to question the accuracy, as long as the setting were on the correct coin type (yet another gotcha!)

I don't think that's correct at all. The cursor colour is merely cosmetic and depends on the age of the unit (firmware version).

 

 

 

[JohnA1]

Best to contact the Sigma people and double-check if the cursor is supposed to be black or not for the serial number (or firmware) of the unit.

Otherwise you'd think that something is not plated when in fact it is.

The sigma pro also has a way to tell you that you are not getting a reliable reading. It caught me out once.

[paulmerton]

8 minutes ago, JohnA1 said:

Best to contact the Sigma people and double-check if the cursor is supposed to be black or not for the serial number (or firmware) of the unit.

Otherwise you'd think that something is not plated when in fact it is.

The sigma pro also has a way to tell you that you are not getting a reliable reading. It caught me out once.

If the cursor's filled state was meaningful in any way, it would say something about it in the instructions.

[sixgun]

On 12/06/2023 at 22:51, Spyder said:

This is why I do not buy Gold bars.

Spyder

Obsolutely yes - it cannot be repeated often enough.
i have advised beginners numerous times - do not buy gold bars. They are too easy to fake - and most certainly never buy them on ebay.

[sixgun]

@Roy - how come you ever got yourself into a position where you thought you had picked up something dodgy?

Edited July 17, 2023 by sixgun

[silversky]

On 13/06/2023 at 00:48, jultorsk said:

Yes, PM minted bars are notorious. PM has attempted to educate buyers but these fakes are just too ubiquitous and.. "cheap". 

Most people do not read product manuals, I know I'm one of them. Here's what I found from Sigma PMV Original's Manual:

https://www.sigmametalytics.com/_files/ugd/cdfbbc_a95f61af6c78448bbb91cf8867828c58.pdf 

 

It's all well and good for them to say that it is up to the user "to confirm density separately", but it's not as simple as they then make out.  It is simple if it is a flat sided object.  But cast bars certainly do not have specifications that can be density checked easily.  Simply weighing and measuring with callipers, is good enough for a nice rectangular bar, but it's not so easy with shapes which are non regular.

Measuring the density of large bars is fraught with danger, even when measured using weight and size comparison.  Tungsten happens to be very similar to gold in density, so a gold coated tungsten block, is approx the same size and weight / density.  I'm not sure whether it's para/dia magnetic properties are significantly different such that an ametuer can check that with kitchen equipment.  Unless you have seriously expensive gear I think it's easier to stick to smaller items which can't be so easily mimicked without the gold plate being too thin.  Coins are easier in terms of checking for authenticity.  IMHO.

[silversky]

1 minute ago, silversky said:

It's all well and good for them to say that it is up to the user "to confirm density separately", but it's not as simple as they then make out.  It is simple if it is a flat sided object.  But cast bars certainly do not have specifications that can be density checked easily.  Simply weighing and measuring with callipers, is good enough for a nice rectangular bar, but it's not so easy with shapes which are non regular.

Measuring the density of large bars is fraught with danger, even when measured using weight and size comparison.  Tungsten happens to be very similar to gold in density, so a gold coated tungsten block, is approx the same size and weight / density.  I'm not sure whether it's para/dia magnetic properties are significantly different such that an ametuer can check that with kitchen equipment.  Unless you have seriously expensive gear I think it's easier to stick to smaller items which can't be so easily mimicked without the gold plate being too thin.  Coins are easier in terms of checking for authenticity.  IMHO.

And when it comes to silver, it's easy to check the density and be pretty sure its the real deal.  Nothing else pure has a similar density to silver, and so, it's much harder to counterfeit without going to serious complexity which isn't worth it for silver.  It's certainly possible to make up a multiple fillet, which has identical density, and sort of weakly similar properties, but it would be far more expensive than the silver, hence they don't exist.

Ultimately, coins make plating hard.  Under a loupe, it's pretty easy to see the plating in the corners and the discolorations that occur there.

[Roy]

2 hours ago, sixgun said:

@Roy - how come you ever got yourself into a position where you thought you had picked up something dodgy?

Well, it usually involves lots of alcohol and ladies (?) offering massage, but I find a large dose of penicillin soon clears it up.

As for gold bars, I like the 1g 'cos they aren't worth faking and I buy from the forum so confidence is high 👍

[HerefordBullyun]

7 minutes ago, Roy said:

Well, it usually involves lots of alcohol and ladies (?) offering massage, but I find a large dose of penicillin soon clears it up.

Can you recommend a good doctor asking for a friend.....

[Spyder]

Glad that this thread is still being used.

I have the recorded the fake bar with the sigma. Ignore the scales as I had the wrong settings and the battery needed replacement. The bar again tricked the sigma. Now if I was to just take photos and try to sell the bar to a novice and tell them do not remove from blister pack, they may just do that. Locked it away and one day will find that it is worthless.

Roy has got the correct idea, maybe stick to very tiny bars as they be too thin to try and plate.

 

Replaced the video with a zip file as it was taking too long to watch with buffering all the time

I use VLC player to watch. 

 

20230717_191640_1_1.7z

Edited July 21, 2023 by Spyder

[NGMD]

52 minutes ago, Spyder said:

Glad that this thread is still being used.

I have the recorded the fake bar with the sigma. Ignore the scales as I had the wrong settings and the battery needed replacement. The bar again tricked the sigma. Now if I was to just take photos and try to sell the bar to a novice and tell them do not remove from blister pack, they may just do that. Locked it away and one day will find that it is worthless.

Roy has got the correct idea, maybe stick to very tiny bars as they be too thin to try and plate.

That video took about 10 mins to run.😁

Personally with the smaller bars I always use the small wand and measure four spots a side. Can you show your results using this method?

[silversky]

If you make yourself a little neodymium magnetic slide (or purchase one), you can easily check gold as well as silver.  There is a slight chance of micro scratching the surface of course, which is a downside if you're checking coins or small minted bars with some numismatic value.

Unfortunately however, copper responds in a similar manner to both gold and silver on the magnetic slide, indistinguishable to the inexperienced user.  However, if it's brass that has been plated with gold or silver, it is blatantly obvious.  Combined with a weight and density check it becomes a pretty powerful tool.  I'll get round to filming a little demo at some point.

Three basic tests are a must.

1) Diamagnetic properties. Easier to check on thin items like coins or small bars, and can be done either with a slide to assess speed, or with a small magnet to run across a larger item.

2) Density.  This can very easily be checked for silver items with good assurance.  Callipers for regular shaped items, or fine thread, deionised water, and a set of scales for irregular shaped items such as cast bars.  It's also useful for gold although less reliable.  But it does help to avoid the less sophisticated counterfeits, always bearing in mind that bigger gold items are worth more effort to the counterfeiters.

3) The mark one eyeball and a loupe.  Having a good look under a loupe is invaluable.  Plate can be identified where it has not adhered uniformly, or where subsequent minting of a plated platter has virtually pierced through to the base metal below.  Some time ago, I legally purchased some plated fake coins (which were sold openly as plated commemoratives), and upon examination under the loupe, I could easily see that the plating looks weak around the rim where the 90 deg angle is struck to the face.  The faintest discolouration shows in the internal corner, which amazingly, isn't visible to the naked eye.

And number 4 is to confirm the stated weight.  Thinner faked objects struggle to match weight and density accurately.  One has to be sacrificed over the other.  Check both.  Combined with the sigma (which I don't possess), I imagine this to be a very effective way to keep the counterfeits out of your stack.  The sigma is only one part of the checking process, the other checks should all pass as well.

A disclaimer / reminder to new stackers:  A density check with gold, is no guarantee that you haven't got a sophisticated fake on your hands.  Gold's density is not alone on the periodic table, Tungsten is very close, and it is therefore easier to fake density with gold than it is with silver which is all out on it's own.  The thicker and more expensive an item, the more chance that a sophisticated counterfeiter has produced a clever multiple fillet (I haven't actually seen any but it is theoretically possible) which can nearly (but not quite) match resistive and magnetic properties, as well as achieving correct density and weight.  The use of multiple methods of verification cannot be stressed enough.

[Spyder]

17 minutes ago, NGMD said:

That video took about 10 mins to run.😁

Personally with the smaller bars I always use the small wand and measure four spots a side. Can you show your results using this method?

I do not why it is taken so long to watch. Regarding the wand. Tried all three and all failed at one time or another. Both in and out of blister

11 minutes ago, silversky said:

If you make yourself a little neodymium magnetic slide (or purchase one), you can easily check gold as well as silver.  There is a slight chance of micro scratching the surface of course, which is a downside if you're checking coins or small minted bars with some numismatic value.

Unfortunately however, copper responds in a similar manner to both gold and silver on the magnetic slide, indistinguishable to the inexperienced user.  However, if it's brass that has been plated with gold or silver, it is blatantly obvious.  Combined with a weight and density check it becomes a pretty powerful tool.  I'll get round to filming a little demo at some point.

Three basic tests are a must.

1) Diamagnetic properties. Easier to check on thin items like coins or small bars, and can be done either with a slide to assess speed, or with a small magnet to run across a larger item.

2) Density.  This can very easily be checked for silver items with good assurance.  Callipers for regular shaped items, or fine thread, deionised water, and a set of scales for irregular shaped items such as cast bars.  It's also useful for gold although less reliable.  But it does help to avoid the less sophisticated counterfeits, always bearing in mind that bigger gold items are worth more effort to the counterfeiters.

3) The mark one eyeball and a loupe.  Having a good look under a loupe is invaluable.  Plate can be identified where it has not adhered uniformly, or where subsequent minting of a plated platter has virtually pierced through to the base metal below.  Some time ago, I legally purchased some plated fake coins (which were sold openly as plated commemoratives), and upon examination under the loupe, I could easily see that the plating looks weak around the rim where the 90 deg angle is struck to the face.  The faintest discolouration shows in the internal corner, which amazingly, isn't visible to the naked eye.

And number 4 is to confirm the stated weight.  Thinner faked objects struggle to match weight and density accurately.  One has to be sacrificed over the other.  Check both.  Combined with the sigma (which I don't possess), I imagine this to be a very effective way to keep the counterfeits out of your stack.  The sigma is only one part of the checking process, the other checks should all pass as well.

A disclaimer / reminder to new stackers:  A density check with gold, is no guarantee that you haven't got a sophisticated fake on your hands.  Gold's density is not alone on the periodic table, Tungsten is very close, and it is therefore easier to fake density with gold than it is with silver which is all out on it's own.  The thicker and more expensive an item, the more chance that a sophisticated counterfeiter has produced a clever multiple fillet (I haven't actually seen any but it is theoretically possible) which can nearly (but not quite) match resistive and magnetic properties, as well as achieving correct density and weight.  The use of multiple methods of verification cannot be stressed enough.

These are excellent points when you have the bar in your hand. It completely another case the the bar is left in the blister pack as most people tend to do.

I think that German gold tester as mentioned in the Kee tester thread might work better then the sigma to test for fakes

Edited July 20, 2023 by Spyder

[silversky]

12 minutes ago, Spyder said:

 

These are excellent points when you have the bar in your hand. It completely another case the the bar is left in the blister pack as most people tend to do.

A very good point.  I have avoided the minted bars in blisters precisely for that reason.  I'd rather have it open and check it myself for my own peace of mind.  I realise that the manufacturers have a system of numbers and records to aid with verification, but I haven't looked into how effective they are.  My experience is less than limited when it comes to that security feature.

Have you had a good look under a powerful loupe?  One imagines that it is still possible to carefully examine the surface through the blister pack.  Unless the plate is thick enough, I imagine that there will be issues with the surface.

Edited July 20, 2023 by silversky

[Spyder]

1 minute ago, silversky said:

A very good point.  I have avoided the minted bars in blisters precisely for that reason.  I'd rather have it open and check it myself for my own peace of mind.  I realise that the manufacturers have a system of numbers and records to aid with verification, but I haven't looked into how effective they are.  My experience is less than limited when it comes to that security feature.

Have you had a good look under a powerful loupe?  One imagines that it is still possible to carefully examine the surface through the blister pack.  Unless the plate is thick enough, one imagines that there will be issues with the surface.

The bar is thicker then it should be. A novice will never know this. You can not tell that it is fake until it was filed and one can see that it is not gold. These Perth mints are excellent fakes. If I had a genuine next to this then maybe I might notice, but as I don't It would be difficult while in the blister pack. This is one reason why I buy sovereigns or other gold coins.