Cheap Ping Test!

[SlowFrog]

Hi all,

I wasn't quite sure where to put this one but after browsing a bunch of websites and watching various YouTube channels, I noticed there are some tools/devices out there for holding a coin to do a ping test. I don't know about you but I keep dropping it off my finger every time I try to do it and I didn't want to pay a ridiculous amount for some weird contraption (most of which seem to be outside of the UK anyhow).

After some digging for a suitable tool on Amazon, I found something called a 'fish lip grabber' and purchased one for under 3 quid. My wife also had a pack of self-adhesive little sponge sequins that she uses with my young son to decorate cards etc (I think they're also super cheap). Long story short is that it works a treat for pinging a coin (even with an old copper 2p I found in the garden) and doesn't do any damage either. 

Just posting in case someone else finds it useful!

John

 

[Pete]

Several years ago I spent some time exploring the "ping test" but as you rightly say supporting the coin without dampening it to ensure it "rings" was tricky.
I tested a variety of coins and found the subject quite interesting.
I used the free software Audacity to record the ping and then the frequency analyser to plot the resonant frequencies.
My intention was to create a library of frequencies to share but I didn't have the free time.

[SlowFrog]

I'm intrigued by it too - from the research I've done, it seems like there's only a few relatively inexpensive ways to test for tungsten filled gold coins - ultrasound or ping (apparently, tungsten gives a dead thud with no resonance). As you said, if we had a common way of testing the 'ping' and recorded a library of genuine coins with something like Audacity, then in theory it should be possible to compare the sounds/waveforms. It'd be great to do this on PC rather than using a phone app as it'd be free and probably more accurate. Would be an interesting project but I haven't got enough time either!

BTW, I did just test it with a gold sovereign too and although it isn't loud, you can put it next to your ear due to the easy grip and it 'rings' for ages. The pitch is nice and clear too - unfortunately haven't got a fake to compare against so I may have to get on eBay!

 

Edited July 15, 2021 by SlowFrog

[zxtm99]

Fascinating - I see plastic versions are available very cheaply on eBay. Probably rubbish for grabbing fish lips, but maybe safer on a coin.

[SilverJacks]

Would anyone agree that Maples are a bit thudy in general, regardless of method/technique?

[SlowFrog]

13 minutes ago, zxtm99 said:

Fascinating - I see plastic versions are available very cheaply on eBay. Probably rubbish for grabbing fish lips, but maybe safer on a coin.

I was paranoid about it scratching/damaging coins but the one I got with the little sponges/plastic things are perfect. In all honesty, I don't think it'd damage the coin without them either - it's actually quite lightweight and the edges aren't sharp. The grip is just enough for a coin too - I thought it'd be much stronger but it doesn't hurt at all if you let it squeeze your finger.

[Bigmarc]

2 hours ago, SilverJacks said:

Would anyone agree that Maples are a bit thudy in general, regardless of method/technique?

Yes threw me at first. I generally stick to the magnet test in line with a coin I know is silver. Then I would do a gravity test if unsure.

[SlowFrog]

I have one Maple somewhere so I'll have to try and dig it out and give it a whirl. Got me curious now

[SilverJacks]

They do have greater thickness than most 1oz silver bullion coins... But they definitely do not ping the same, for me anyway 😂

[silenceissilver]

6 hours ago, SlowFrog said:

I'm intrigued by it too - from the research I've done, it seems like there's only a few relatively inexpensive ways to test for tungsten filled gold coins - ultrasound or ping

This is another cheap way of testing if it's tungsten. It's a pretty tedious task though - the price for being inexpensive.

 

[SilverStorm]

 

On 15/07/2021 at 06:09, SlowFrog said:

Hi all,

I wasn't quite sure where to put this one but after browsing a bunch of websites and watching various YouTube channels, I noticed there are some tools/devices out there for holding a coin to do a ping test. I don't know about you but I keep dropping it off my finger every time I try to do it and I didn't want to pay a ridiculous amount for some weird contraption (most of which seem to be outside of the UK anyhow).

After some digging for a suitable tool on Amazon, I found something called a 'fish lip grabber' and purchased one for under 3 quid. My wife also had a pack of self-adhesive little sponge sequins that she uses with my young son to decorate cards etc (I think they're also super cheap). Long story short is that it works a treat for pinging a coin (even with an old copper 2p I found in the garden) and doesn't do any damage either. 

Just posting in case someone else finds it useful!

John

 

I posted the Pocket Pinger on the general precious metals sub-forum last month.  Your DIY method is definitely more cost effective!   Note: as mentioned in the Pocket Pinger thread, the plastic nubs will leave marks.  And by extension, your plastic nubs on your DIY tool will too.   Just make sure that if you use your DIY tool, you are not testing numismatic coins or any precious metal that you would not touch with your bare hands.   See the link below for more details.

link: 

 

 

On 15/07/2021 at 07:53, SilverJacks said:

Would anyone agree that Maples are a bit thudy in general, regardless of method/technique?

Yes agree, silver maples don't "ping" like other coins do.   I do find that odd.

Edited July 16, 2021 by SilverStorm

[SlowFrog]

Thanks for the info! I've not yet seen any marks left by my DIY thing but I haven't tested it with any proof-like coins and don't think I would - especially given what you've just said. There's quite a choice of 'nubs' out there for the DIY one because it has a flat surface - you can find all sorts of self-adhesive options made of silicone, hard plastic, rubber, sponge etc. The coloured things I stuck to the pink sponges are hemispheric in shape and hard plastic - it means the surface area touching the coin is absolutely minimal which I believe would also enable the coin to ring better but I have absolutely no scientific proof to back that up! 

[newshoes]

The ping test (to me) is literally as simple as placing the silver coin on top of your first finger & thumbnail area and flicking it off your thumbnail into the air. Nothing to it and no extra tools needed apart from the ones you were born with. A 1 Oz silver coin will make a very clear and beautiful "ping" sound as it twirls through the air.

 

Other ways to test for a silver coin are the obvious size & weight measurements & comparisons, and intriguingly, another one works with a strong neodymium magnet.

 

Hold the coin at 45 degrees or a bit steeper on a flat surface, then place the small strong neodymium magnet at the top and marvel at how it SLOWLY slides down the surface. If you tried the same thing with a UK 5p or 1p coin they would instantly crash to the bottom. Not so with the magnet. Is the magnet attracted to silver? No it isn't.

 

How does this work?

 

The answer is that the (strong) magnet induces eddy currents in the silver as it slides down which then slows its descent. That trick works with pure silver & pure gold coins. It won't work with a Krugerrand because the Kruger isn't pure gold and is alloyed with a small amount of copper.

 

Try it and see for yourselves. Ain't science marvellous.

 

As stated, you must use a neodymium magnet, preferably a small round one shaped like a small coincell.

 

Remember, the more tests your gold or silver coin passes, the more likely it is to be genuine. It is much easier to fake one or the other characteristic of a pure gold or silver coin, but it becomes exponentially more difficult to fake them all.

Edited July 16, 2021 by newshoes