No Way to Detect Fake 100oz bars?

[buggles]

Silver and Lead have extremely similar specific gravities and densities. As a result I would expect that X-rays have the same penetration issues with silver experienced with lead. I do not, however, have any information that verifies such a statement; it just stands to reason.

[Irons]

I only buy 10oz bars and under just because of that.If theres a way to rip someone off it will be found and used, sorry to say.

The other reason I like to keep the bars small is to cash in under the tax radar
if possible.
The other thing is are you going to pay $5000 for a silver bar without an assay sheet on it when this really go's up?Even $2000 at todays prices is more than I would chance without a full pedigree on the bar with the serial ##'s on it.But thats just me.

[Irons]

OK! This just keeps getting better! After looking at my hundred oz. bars, I decided to examine some 10 oz. poured bars I purchased (same dealer) a short time after...and WOW! If someone here can give a better explanantion about how to upload photos to these posts, I can stick em up and see what y'all think....I'm really suprised this wasn't obvious to me right off...

click post reply,then click the paper clip icon next to the smiley face, a new window will come up click browse, your pictures, click on a pic, then click open,then upload.when the upload is complete x the wnidow away and click the paper clip again.your uploaded image will be there.click on it and it will be put into your post.

[Drumblebum]

Thanks Irons... you bring up some good points concerning the bigger bars, especially about when the price goes up!

I appreciate the rundown on posting the pics. I'm going to have to resize these as they are apparently too large to post.

At any rate I took the bars down to a coin dealer I do business with and they had a look at the 100's and 10's I was concerned about. Said that they doubted they were drill and fills but noted that the one bar had indeed been shaved for at least 3 oz. They didn't have a scale with the proper capacity so they couldn't verify the toal loss but suggested strongly that I put some pressure on APMEX to exchange the bar as it is not what I paid for.

I appreciate everyone's input on this...

[TomAlciere]

Keep in mind that I have no idea what I'm talking about, but vending machines test coins by running electricity through them. There's gotta be a way to do that with silver, timing how many picoseconds it takes electricity to run through the bar, and thereby tell if the electricity is going straight or around some lead.

Then there were the guys who were making fake silver bars by drilling genuine 100 oz bars, taking out some of the silver, and replacing it with gold. They weren't very smart.

webmaster@silverismoney.info

[DaveK]

Absolutely you can test by checking the electrical conductivity. However, as was noted several times in the goldismoney forum discussion linked by the OP, you aren't going to be able to use a typical hand-held VOM to do the test.

I don't have a 100 oz bar to measure, but judging by the pictures I see and a quick calculation they are very close to 1x3x6 inches.

With a resistivity of 1.59*10-8 ohm-meters a standard solid silver bar would measure, end to end, somewhere around 1.25 microohms. That is a very small resistance. Consider that a 22 gauge copper wire the length of the bar would be about 0.01 ohms, or 10,000 times as much.

This pretty much eliminates the option of directly testing via resistance, as the contact resistance of your measuring device is going to be more than the total resistance bar. I think it could be done, but the measuring device would have to be reasonable sophisticated.

For fun though, assuming that a silver bar is drilled and filled end-to-end with three pure lead rods 0.75 inches in diameter, we can calculate the approximate resistance of the filled bar by modeling the system as two parallel resistances, one of lead, one of silver.

This works out to, if my math is right, about 2.13 microohms for the filled bar, about 1.7 times the resistance. (assuming 2.2*10^-7 ohm-meters for lead)

Another option for testing would would be to measure the conductivity of the bar indirectly by measuring the inductive drag between the bar and a magnet. As you know, if you pass a very strong magnet over a conductive surface, such as a thick plate of highly conductive silver, a very strong counterforce to the movement of the magnet (or bar, whichever) is produced. This is a result of the electrical current induced into the bar by the moving magnetic field. The magnitude of the current is a function of the conductivity of the metal and the strength of the magnet, thus the magnitude of the counterforce is directly related to the conductivity of the bar. The less conductive the bar, the easier it is to slide it past the magnet.

So, a simple test system would be a set of high strength magnets arranged as a Halbach array, a set of standard silver bars for calibration, and an electronic optical timer. The device consists of the magnet array mounted in the surface of a sloped ramp down which rolls a sled containing the bar to be tested. As the sled rolls down the ramp under constant gravitational acceleration optical sensors time the travel of the leading edge of the bar.

A solid silver bar should experience noticeably greater deceleration than a bar the same dimensions and weight that has been drilled and filled with lead.

Of course to develop such a device you'd need some samples of fake 100oz bars for testing. Such a device could be made for under $100. Unless you wanted it to be pretty or fancy. A fancy version might include a USB connection for software on a computer to direct testing.

[Daveman]

Okay, would the "ring" test still work (or work at all) on 100 oz, or even 10 oz silver bars as well as silver coins?

[DaveK]

Intuition sure says that a lead-filled bar would not ring very well. But again, this is something you'd have to try before you could know for sure how obvious the difference was. It might be a subtle difference, or it might be obvious, it's hard to know for sure without giving it a try.

Anybody want to drill and fill a 100oz bar and give some tests a try?

[hekura]

I'm holding out for a few days, closely watching the market, but I will have five of them very soon. I would sacrifice the integrity of one of them to analysis. from a purely scientific perspective, though, displacement vs. weight, should be all the measurement that is required, as alloys closely matching the specific gravity of silver would be cost prohibitive to produce, and would include the provision of transducing metals such as platinum, palladium, or tungsten, to closely imitate. I figure a 1/16th inch borehole would be worth the insurance of my investment, but hey, hats off to the guy that creates this effective counterfeit. I see possibilities for the use of lead, copper or nickel or zinc, and tin, as used by our prestigious government, to water down the value of our nation...but there is really no substitute for the look and feel of silver. By weight and displacement, I would give a 99% accuracy rating...same for the look, feel, ring test...but that's me. A SOLID (appearing) counterfeit would involve a two-stage casting/stamping process. (HHHhhmmmmmmmm...tungsten, tin, lead, North Korea...nahhhhhhhhhhhh.)

But, HEY, I'll go drillin'. I'm in long anyway, always have been, but I've never had a number of identical 100's to experiment with. Let me know if you're still interested in this experiment next week.

J

[Daveman]

Even if the bar's filled with lead, there should be at least 50oz worth of silver left in an 100oz bar anyhow, right? They can't fill the bar with some 75% lead as the silver plating would then be too thin?

So I can still get to sell 50oz worth of silver even in a lead-filled bar?