We have a page that attempts to summarize all information on the Internet about lead-filled 100 ounce silver bars, as well as provide some new thoughts and insight.
Here, we discuss one of the two types of lead-filled silver bars, the hollowed-out version (as opposed to the original 3 drilled holes version). We were able to obtain hundreds of page of information from the FBI, some of which was very useful. This page is designed to provide information to help detect the bars, and to understand more about the operation that created them.
NOTE: We are actively seeking one of each type of lead-filled silver bar to run tests on, but have been unable to do so. Please if you have one you would sell us or let us borrow. Thank you!
|Step 1: Buy real silver bars||The people behind the hollowed-out silver bars bought real 100 ounce Engelhard silver bars (from dealers in New York, Connecticut, and elsewhere). It is important to buy unadulterated bars; if they are already lead-filled, it defeats the purpose.|
|Step 2: Cut off the ends||The first step, after buying the real bars, was to cut off both ends (the 'top' and 'bottom', more accurately described as the left and right ends if the bar is on a flat surface with the Engelhard logo facing you).|
|Step 3: Drill 4 holes||In this step, you drill 4 holes, all the way through the bar. They start at either the left or right side (if the bar is facing with the logo side facing you), and go all the way through the bar. The holes are made in each of the 4 corners.|
|Step 4: Saw between the 4 holes||Once you have drilled the 4 holes, you use a saw to cut out the silver in the middle of the bar. At this point, you have a small rectangular piece of silver weighing about 60 ounces, and the shell of the original bar (which you can now see through from one end to the other).|
|Step 5: Drill a fill hole||Now, you need to drill a 'fill hole', which you will later use to insert the molten lead. It is drilled into 'one side of the bar', presumably either the front side or the back side (since the ends were cut off, and the front and back of the bar would be more likely to be closely inspected).|
|Step 6: Put new ends on the bars||At this point, you need to put ends back on the bars. Rather than use the ends that were cut off, you are going to use silver plates custom-made for this purpose. It is unclear why silver plates are needed, rather than the original ends that were cut off. It is also not clear how they were attached (it appears to have been with a special solder, using a tungsten alloy to increase the melting point, to prevent the molten lead from melting the solder).|
|Step 7: Fill the bar with lead||You now have a bar that appears fairly normal -- except that it has a fill hole, and it is visually obvious that the ends were re-affixed. And it only weighs about 30 ounces or so, not 100. So you pressure fill it with molten lead, using a machine custom made for the purpose.|
|Step 8: Insert a silver plug||At this point, you have one blatant problem with the bar: there's a fill hole visible, and you can see the lead inside the bar. So you now insert a silver plug into the hole. Although the term 'silver plug' was used, it was more likely that molten silver was used. Otherwise, the hole would be much more noticeable.|
|Step 9: Finish the bar||You now have a bar that appears normal, except that it is (intentionally) slightly overweight, and there are marks where you added the ends on and the plug. So you need to finish the bar, by smoothing out the areas where the bar had been cut or drilled, and keep working at it until the weight is exact.|
|Step 10: Sell it all||Now, you sell the bar, as well as the silver that you took out of it.|
The only information we saw from the details of the case was that when they obtained 10 bars from a customer, "Visual inspection of these bars indicated a probability that at least four (4) bars may have been altered." That implies that by looking at them (perhaps knowing what to look for, perhaps not) it is possible to distinguish them from real bars.
From careful analysis of the documents we obtained, it appears that the 10 bars were received on 11/18/1993, and the visual inspection was done at the location of the bars before taking them as evidence. This was before bars were sent to the Naval Ship Yard for nondestructive testing, but presumably after the sawing and testing of the original bars. So at that point, the agents may have known what to look for. Interestingly, after we identified the batch of bars and cross-referenced them to the results of testing, we found out that 7 of the 10 bars were lead-filled. So it appears that the agents were able to positively identify 4 as being suspect, but it was unclear whether 3 others were real or not.
However, we also have information from an FBI Special Agent that visual inspection by Engelhard of Carteret, New Jersey and inspection and weighing by the U.S. Mint provided no indication of adulteration. Oddly, that information did not appear in the case materials that the FBI sent. So it could have just been a receptionist that looked at the bars, and said "Yes, those are the kind we make." Or, it may be that experts there examined the lead-filled bars, and couldn't tell them from real ones. We don't know.