Taylor7

On 10/22/2022 at 5:22 AM, EagleRJO said:

I put brackets around my edit if that helps clarify your misconception.

As I pointed out, with silver clad vs cu-no clad SG is not a useful test because of the unknown thickness of the layers, but you’ve made it clear you’re not here to have a useful discussion or learn, simply to discredit me. 

I like how you edited your comment to include mention of YouTube while I was still writing mine. Funny. Probably related to why I would unplug my XRFs Ethernet cable if I had one. All you can say is junk science now that I have proof of your meddling you petulant clown. 
 

by the way, the other silver ‘71-D half graded by NGC also weighed only 11.3g. SG wouldn’t tell you the thickness of the silver vs clad layer anyway, which probably varies a lot and accounts for the weight variability. Your attempts to discredit me and discourage people from transacting with me are hilariously immature. You should probably seek psychiatric care for your obsession with someone you don’t know. Cease and desist this nonsense. 

if you weren't aware, there is an amazing website called "google" that lets you perform a search of all the websites on the internet. This other useful website, "youtube" even has countless videos on a wide variety of subjects. Using either you would find this is introductory chemistry stuff and not the subject of peer reviewed scientific literature of the past few centuries. Don't feel bad, frankly I'm embarrassed I didn't think of doing this sooner. 

You could also just do the experiment yourself. You're on a coin forum so chances are you have some junk silver and cu-ni clad coins lying around. You may not know this, but those coins and also the green paper rectangles they are often exchanged for can be used at places called "stores" as a standard unit of barter for goods like an "egg" (they usually come in packs of 12 in the refrigerated part of the store (the cold part). Eggs are a common food in most parts of the world and come from "chickens", which are a type of "bird", but if you can't find a store you might also try following a bird back to its nest. If you don't know what a bird is, its the animal commonly depicted on the reverse of american coinage. You will need a sealable container, also known as "tupperware", a small pot to boil the eggs with. Water, and a stove (gas or electric will do, but you should probably ask for help from your parent as fire and boiling water can burn you, FYI). 

Any other questions?

[deleted]

I found a way to test for silver at home that's cheap, easy, reliable, relatively fast (few hours), can test many coins at once, and is 100% accurate (unlike a scale). 

Lo and behold, this 1971-D Kennedy half erroneously struck on a 40% silver planchet! Perhaps the finest known! I'll be making a listing for it on the BST forum shortly. 

My digital scale from Amazon (maxus brand) says this coin weighs 11.32g. Funny though, even though I've calibrated it it seems to underweigh halves and overweigh pennies. Regardless, the tolerance on halves is so wide ***weighing the coin is not an accurate test***

RWB, thank you for making me doubt XRF. Indeed I was told a silver coin was cu-ni. Even have a photo of the machine results. Not sure if it was the shop clerks error or if they should unplug its ethernet cable, if you know what I mean. (I would if I ran a jewelry/coin/bullion shop). 

So how does this test work? Simply place the coin in a sealed container for several hours with some chopped up hardboiled egg whites (not touching, just in the same container). The sulphur in one of the proteins will evaporate and tone the silver in mere hours. I set the container in sunlight to speed it up. I had the coins I tested partially sticking out of their mylar flips so it would be easier to see the difference (see the gold tone on the upper right third in the photo).

The only drawback is this is probably considered artificial toning, so it will need restoration when it does get sent in for grading. 

Sure enough, at least one of the coins I suspected was silver is indeed, and what a gorgeous one at that. Auction records (that I've found so far) are $9,900 for an AU 50-something example and $13,000 for an MS61 on 4-20 2018. 

What do you think mine will grade? Not waiting to grade it to sell it though! Pazuzu's student loan payments are past due!

How do I search auction records for error coins by the way? Is there a way to view populations of them on any of the grading companies sites?

On 10/11/2022 at 4:37 PM, VKurtB said:

Trust me - if you think you have “a lot of coins” on wrong planchets, it’s you that are wrong. They are exceptionally rare. 

I’m aware of that, but I’m going through collections I inherited and bought at estate sales not just roll hunting, so it’s quite possible I’m looking at a lifetime of coins set aside because they “look funny”. XRF is a rather new development, like grading, and these collections pre-date those and have already yielded some rather impressive finds so testing is worth pursuing, I just can’t afford $100+ to send each suspected coin off. And like I said, coins aren’t all I want to test. 

I have a lot of coins, both American and foreign, I suspect are on wrong planchets, and coins aren’t the only thing I want to test. 
 

So how do I calibrate an XRF? I might just pretend to be a service tech or print the user manual and procure whatever samples I need for calibration. 
 

All I asked was what shops in the Dallas metro have one. My efforts to call around have failed, thought this community might know. Might as well extend the search to anywhere in Texas. 

A copper-nickel clad Kennedy Half ways 11.36g and a silver clad weighs 11.50g. Their tolerance is much greater than 0.14g, so its really not that simple. Maybe I'll find a way to do a high accuracy resistivity measurement, or get a ~300nm UVC LED and something that fluoresces and make an apparatus to reflect that light off the coin, since silver is much less reflective around that wavelength. 

I didn't realize just how low the population was when I asked. I'm more interested in distinguishing a polished coin from a brilliant proof, and a satin/matte proof from a business strike. What features of the coin do you see the most difference in? Sorry I can't afford to buy another book right now, I was just hoping to have more experienced coin collectors point out a specific part of the coin with a striking difference. Pun intended. 

surely they can tell the difference between copper-nickel and silver, even if not calibrated. I can understand it being off a few %, or mistaking the chorine in paper for trace amounts of palladium since their emission lines are close, but they should be able to tell me if a coin is 95% copper vs 75% vs 10% 

if not, how would you recommend testing a coin for its metal content without paying to send it in?

I've called around but the only shop with an XRF I could find is on the other side of the metro from me, and has their machine in the back which totally defeats the purpose of doing XRF where the customer can see the results themselves. I have a few coins I think are on the wrong planchet but can't afford the price of grading + metallurgic testing. 

Also interested in hearing about at home tests that don't damage the coin if you know of any. Obviously weighing the coin is the first, but the tolerances on coins like Kennedy halves are greater than the difference between 40% silver and Copper-Nickel clad. 

There's also the tissue paper test but I don't want to clean anything and the dark toning makes that test hard to interpret. 

does anyone know of at least a youtube video of someone handling a graded example? Much easier to see the difference in texture that way. I say graded because like with lots of other rare coins there are plenty of delusional, mistaken, or outright scammers on youtube claiming to have a proof peace dollar or aluminum cent and handling it raw with no gloves, lol. 

ah, just checked my Judd book and I was thinking of the '76

On 10/9/2022 at 5:10 PM, J P M said:

Welcome foundit .. Cool I would like to see them. 

 

Welcome Taylor....Who is Judd ?

Thanks!

Judd wrote the book on Pattern coins, usually if you get one graded it will have Judd-#### on the label. I'm still not clear on the difference between patterns, prototypes, and trial strikes. Website below is also useful. 

https://www.amazon.com/United-States-Pattern-Coins-Experimental/dp/0794818234/ref=sr_1_2?qid=1665355912&refinements=p_27%3AJ.+Hewitt+Judd&s=books&sr=1-2&text=J.+Hewitt+Judd

https://uspatterns.stores.yahoo.net/

Lets say I have a coin that's dated first year of issue, and has some aspects of the design that don't match any variety on NGC, variety vista, PCGS, VAM world, etc so I suspect it might be a pattern/prototype and want to get it graded, more for the sake of keeping it preserved and giving numismatists the chance to study it than the money. Though I do need the money if it turns out to be what I think it is I'd prefer to sell it to someone who will donate or loan it to a museum. So what do I do? The thought of putting it in the mail (even with a lot of insurance, which I can't afford) puts a pit in my stomach. PCGS told me they can't look at the photo I emailed them and tell me anything, which I understand completely. NGC didn't respond to my email, also understandable.

Smithsonian doesn't take artifacts on loan, only donations, which I would consider if I didn't need the money. 

Are there any museums I could loan it to for a few months? Is it a faux-pa to ask a museum if they would like to purchase it from me and to ask for their offer? 

Thanks

On 10/8/2022 at 6:50 PM, VKurtB said:

A few years back, I was judging exhibits for the Maryland State Association at Baltimore, and somebody had some special presidential “blue Ikes” with special packaging and a facsimile letter with a Nixon signature. They were absolutely 1971-S Ikes but could that occasion be attached to these prototypes in some way? There was no opportunity to examine the reverses up close. 

Do you remember if it actually had the S mint mark? I think Judd lists a 71 proof with no S as a pattern or presentation piece

I don't see how y'all can give OP a clear answer on these with the low quality of photos. 

Are there any diagnostics that aren't ambiguous? Is being "shiny" enough for the brilliant proofs? Any die chips or polishing lines or features on the design that really make the difference clear?

I know when looking at UNC coins the wideness of the rim is an obvious difference, but I'm more interested in diagnostics that would still be clear with moderate wear. 

Thanks