Limitations of the Sigma pmv original

[universalcurrency]

This is probably a question for other sigma pmv original owners.

Having recently acquired a sigma pmv original I was keen to put it through it paces and find out what it could and couldn't do.

I found it worked well with all the gold I could throw at it, including capsules and blister packs. Although I did have some difficulty with a rattley Baird blister pack. The air gap confused the sensor, so I put one of the wands under the bar and got a positive reading.

Next I tried it on 999 + 9999 silver rounds and bars which worked great. However it does struggle with high relief coins, but in most cases taking the coin out of the capsule and using the wands works.

I have yet to test platinum, palladium and rhodium or have any success with copper. Does anyone have any experience testing these metals?

Also I haven't had much success with the calibration disk, which I understand also helps with using thin samples, any suggestions?

[arphethean]

17 minutes ago, universalcurrency said:

This is probably a question for other sigma pmv original owners.

Having recently acquired a sigma pmv original I was keen to put it through it paces and find out what it could and couldn't do.

I found it worked well with all the gold I could throw at it, including capsules and blister packs. Although I did have some difficulty with a rattley Baird blister pack. The air gap confused the sensor, so I put one of the wands under the bar and got a positive reading.

Next I tried it on 999 + 9999 silver rounds and bars which worked great. However it does struggle with high relief coins, but in most cases taking the coin out of the capsule and using the wands works.

I have yet to test platinum, palladium and rhodium or have any success with copper. Does anyone have any experience testing these metals?

Also I haven't had much success with the calibration disk, which I understand also helps with using thin samples, any suggestions?

Gold

the sigma only does 90%, 22ct and 999 gold. No use for 14ct or 9ct etc. For those purposes the Kee is the best.

Also it does not work for extremely thin, small gold, such as grams or smaller. Also, very hit and miss through slabs or thick capsules for anything other than ounces, £5 etc

 

Silver

Generally pretty reliable, although some sterling silver coins are out of the brackets. 

High relief - yes, can definitely struggle with non-flat items or messy textures unless they fully cover the circle on the unit sensor

 

Copper - not supported

Platinum, palladium - works fine

Rhodium - not tried

Edited March 26, 2023 by arphethean

[paulmerton]

Also remember that it only tells you if the sample you're testing has the same resistivity as the metal you hope it to be. It doesn't mean it is the same metal.

I have a copper bar that comes up as a perfect match for its 92.5% sterling silver setting for example. Don't rely on it as the sole means for verifying that something is legitimate, but you can certainly rely on it when it says something isn't a match.

20 minutes ago, arphethean said:

Copper - not supported

Mine supports copper out of the box.

[universalcurrency]

14 minutes ago, arphethean said:

Gold

the sigma only does 90%, 22ct and 999 gold. No use for 14ct or 9ct etc. For those purposes the Kee is the best.

Also it does not work for extremely thin, small gold, such as grams or smaller. Also, very hit and miss through slabs or thick capsules for anything other than ounces, £5 etc

 

Silver

Generally pretty reliable, although some sterling silver coins are out of the brackets. 

High relief - yes, can definitely struggle with non-flat items or messy textures unless they fully cover the circle on the unit sensor

 

Copper - not supported

Platinum, palladium - works fine

Rhodium - not tried

The sigma machine I have says it will handle copper, but in the instructions its not too specific what the criteria is. Btw copper is in the other metals menu with platinum etc.

For anyone considering getting one,I would have to say that it covers most bases for pm stackers/collectors and is exceptional value compared to say an xrf tester. However without the wands its userbility is quite limited, so I would say that that the wands are essential.

[JohnA1]

When I did a deep dive on the original PMV the biggest limitation that bugged me was the number of microns it can go through.

This varies with metal composition and wand size, but still it is only really adequate for detecting plating.

Not good enough for my paranoia - after  seeing pictures of coins and bars with tungsten inserts, there was no going back. Such fakes would show as legit on the original PMV😬

Edited March 26, 2023 by JohnA1

[iacabu]

Only tested a few things since getting mine. 

My pocket piece, an 1889 Crown, shows outside the brackets for .925 silver. 

Won't pick up the small gold, even with the wand. I did stack a few of the same 0.5g gold to test it and it started to give a reading, though outside of the brackets. 

I did see an option for copper, yet to be tested. 

As already mentioned, it's so concerning about these fakes shown on various videos recently. The ping test was a clear cut result for one of the coins though. Use a variety of methods and you should be OK. 

 

[arphethean]

23 minutes ago, Iacabu said:

Only tested a few things since getting mine. 

My pocket piece, an 1889 Crown, shows outside the brackets for .925 silver. 

Won't pick up the small gold, even with the wand. I did stack a few of the same 0.5g gold to test it and it started to give a reading, though outside of the brackets. 

I did see an option for copper, yet to be tested. 

As already mentioned, it's so concerning about these fakes shown on various videos recently. The ping test was a clear cut result for one of the coins though. Use a variety of methods and you should be OK. 

 

Try sandwiching with the callibration disc behind it. May pick it up but half grams are very thin and small

Edited March 30, 2023 by arphethean

[iacabu]

5 minutes ago, arphethean said:

Try sandwiching with the callibration disc behind it. May pick it up but half grams are very thin and small

Thanks, I'll try that. Out of interest, why would the disc help with the result?

 

[JohnA1]

32 minutes ago, Iacabu said:

Only tested a few things since getting mine. 

My pocket piece, an 1889 Crown, shows outside the brackets for .925 silver. 

Won't pick up the small gold, even with the wand. I did stack a few of the same 0.5g gold to test it and it started to give a reading, though outside of the brackets. 

I did see an option for copper, yet to be tested. 

As already mentioned, it's so concerning about these fakes shown on various videos recently. The ping test was a clear cut result for one of the coins though. Use a variety of methods and you should be OK. 

 

Looking at the picture above, I would never use the wand so close to the PMV, let alone with the coin sitting on the PMV. It interferes.

It has to be on the side, away from other magnetic and metal objects

[arphethean]

7 minutes ago, Iacabu said:

Thanks, I'll try that. Out of interest, why would the disc help with the result?

 

Don't actually know. It just mentions that in the manual. I do what I'm told and don't think too much

Edited March 30, 2023 by arphethean

[paulmerton]

5 minutes ago, Iacabu said:

Thanks, I'll try that. Out of interest, why would the disc help with the result?

 

It's well worth reading the manual and technical guide in full before trying to make sense of how to use it, how to interpret the results, and how to recognise its limitations.

Fortunately they're all in PDF format on their website so I had a couple of weeks to read them before it even arrived 🤣

[iacabu]

Well I've learnt something from this thread. Haven't had more than a few minutes playing with it yet so I'll read the manual and try again!