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Replies: 68 / Views: 9,311 |
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Moderator
 United States
189142 Posts |
I did not see your link earlier. I thought we were referencing the one in Bret's video.
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Pillar of the Community
United States
1913 Posts |
Guys, this is simple. You can get free scanning if you have a hot wife or girlfriend. Take her to the coin show with you. Look around and find a bullion dealer with a scanner and then get her to ask him to scan the coin(s) to verify that they're real. 9/10 times, they'll do it for free. Of course, your wife or girlfriend might find some jewelry that she wants, so that might ruin your cost. On second thought, perhaps it's better to just ask if they'll scan it for you and pay a few bucks if necessary. Or, as previously stated, send it off to an authentication service. Don't forget that you'll need to pay shipping insurance both ways.
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Forum Dad
 United States
24170 Posts |
Quote: Absolutely. Scanners tell you the exact metal content of the entire object. I first saw one used at a coin show when I was selling a couple of 1oz gold bars. We agreed on a sale at spot, the buyer got out his scan gun and he scanned both bars. I've since seen them used by the bullion buyers/sellers on several occasions. I used to think the same thing. Not true. Had it proven to me at the last FUN show CCF set up at. Guy had a Chinese tungsten core plated gold gar that was cut in half. Plated about 20 microns. Read as gold all day long on the plating with a 17K hand held XRF scanner.
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Pillar of the Community
 United States
6514 Posts |
That makes more sense to me. The scientist in me was trying to figure out how a scanner could possibly scan the entire mass of an object.
Check out my counterstamped Lincoln Cent collection: http://goccf.com/t/303507
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Pillar of the Community
United States
1913 Posts |
bobby, not questioning what you saw. It just doesn't make sense to me how they could sell a scanner to anyone if it only scanned the surface. I don't see people investing thousands upon thousands of dollars in them for what would basically be no return on investment.
A scanner can scan the entire mass of an object just the same as it can scan a few microns in to the same object. Think about how a CAT scan machine works. It can tell you density all the way through an object to create a 3D image. The frequency of the rays that reflect back to the scanner let it know which metals have been detected.
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Forum Dad
 United States
24170 Posts |
Well, The guy that showed me was selling them. His name was Mark Fashian. He told me portables go 8-12 microns at best and that depends on the metal because some metals resist/deflect the rays more than others.
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Pillar of the Community
United States
2023 Posts |
Here's a manufacturer of XRF scanners: https://www.olympus-ims.com/en/webi...r-regulaton/Quote: Question: You mentioned XRF is surface technique? What is the depth of measurement? Can you analyse metal under the paint or anodized layer (aluminum alloy)? For light plastics or light organic materials, penetration is on the order of mm or cm. For heavier plastics (like PVC), or plastics with metallic additives (like Ti, Zn), or aluminum alloys, penetration is on the order of a few mm. For heavier metal alloys (Ti, Fe, etc) penetration is on the order of 100s of um, and for the heaviest metals (gold, lead, etc) penetration is a few 10s of um. The "X" in "XRF" stands for X-ray, and like most forms of light it cannot penetrate metal very far. (Think: why bones in X-rays are white -- the film is not exposed to the rays that did not penetrate the bone.)
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Pillar of the Community
United States
4901 Posts |
Quote: Unlike in other testing methods, plating and surface features do not significantly impact the unit's ability to measure the underlying metal. Using electromagnetic waves that penetrate deeply into the coin or bar, plating and surface features are largely ignored, and the main body of metal assessed.
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Moderator
 United States
54282 Posts |
Well, if the coin is split in two, then the inside can be analyzed.
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Pillar of the Community
United States
2023 Posts |
For context, the quote that Foxwoods Man posted above is from https://sdbullion.com/gold-and-silv...a-metalytics -- the scanner there is not an XRF type; the underlying technology is "electromagnetic waves". We have been talking about two different kinds of scanners. Most mentions on this board (at least those I've seen) have been about the XRF type. This is the first I've seen on this kind. It's a shame that the link doesn't go into more detail about how this tech works, and it was the first hit for the search terms I just used. I don't have time to research this any further right now -- it may be worth a separate thread.
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Pillar of the Community
United States
4901 Posts |
This was the suggestion as a possibility: Quote: The simple solution here would to have had the coins in question scanned. ..and a link to an expensive example was given. I just added an alternative offered by a reputable bullion dealer that I thought sounded reasonable, effective and not that expensive.
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Moderator
 United States
189142 Posts |
Quote: Well, if the coin is split in two, then the inside can be analyzed.  Quote: the scanner there is not an XRF type; the underlying technology is "electromagnetic waves". Not to be pedantic, but x-rays are electromagnetic waves.  Yeah, I know, the "electromagnetic waves" used in that device are probably not x-rays. Not sure what part(s) of the spectrum it uses.
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Pillar of the Community
United States
509 Posts |
Oh that breaks my heart to see. But now you know. BTW: those are great pictures when you see them enlarged. Nice job.
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New Member
 France
11 Posts |
Quote: A genuine solid gold coin would not have a layer that peels back like shown in the image I posted yesterday. *** Edited by Staff to add Quote tags. Please use them in the future. ***Hi, it is not really peeling, it is, I think, because of the tools I used to bend the coin. At first I tried with only one cutting pliers, but it was too strong. I needed an other cutting plier to bend 2 times the coin until it "broke" Before to end cutted in two, The coin was tested with a touchstone. It was fine. My fear was it could be filled with tungsten. What made me think that was the difference of weight beetwen what I've read on internet and what I have seen on my scale. I learnt (few days later), from a very friendly gold seller, that The US Mint is known for not-so-exact measures and that my scale might be slightly off-balance too. @jst1dreamr : this is true, the pictures look good. they were taken with an iphone X. I was impressed by its ability to focus so close to the coin (other than that the phone does not worth its price and the faceID is very bored..)
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New Member
 France
11 Posts |
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Replies: 68 / Views: 9,311 |
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