clogs, die faults, et al.

[PWA 1967]

19 minutes ago, mrbadexample said:

Hang on, I need two people interested to drive the price up, and Nordle's declared out. Anyone else? 

Well i am definately out 

[IanB]

The 1 pence looks like it has been etched with acid, the unexposed bits had a resist painted on and then the coin placed in a solution of whatever acid will eat away the unprotected parts. left in just long enough to strip away the first few microns.

[PWA 1967]

So i think Ian is out aswell

[Nordle11]

1 minute ago, IanB said:

The 1 pence looks like it has been etched with acid, the unexposed bits had a resist painted on and then the coin placed in a solution of whatever acid will eat away the unprotected parts. left in just long enough to strip away the first few microns.

Wouldn't hesitate to agree with that logic. Very strange to have such uniform shapes with lamination errors.

[bhx7]

Think after Ian's observation that would also rule me out. Post mint so not as interested. Still a very unusual piece. Thought it was strange being so uniform.

[mrbadexample]

29 minutes ago, IanB said:

The 1 pence looks like it has been etched with acid, the unexposed bits had a resist painted on and then the coin placed in a solution of whatever acid will eat away the unprotected parts. left in just long enough to strip away the first few microns.

Thanks IanB. I can see why you might think that, but I'm not entirely convinced. Coin in hand, it doesn't look like the work of acid (to my untrained, non-metallurgist, non mint-error expert eye). 

Is there anything I can look for that would indicate the work of acid? That's the highest resolution my scanner will do so I'm struggling a bit for magnification. Is there anything I can look for that would suggest it's a mint error rather than post-mint?

Is there anyone nearby that fancies a closer look? 

 

P.S. Just so we're clear, I didn't join the forum to sell a dodgy 1p. 

[IanB]

If it is acid the etched surface will probable look grainy, also as it etches the vertical sides may start to undercut as they are exposed to the acid but I imagine it was not left in to long as the etched surface still has plenty of detail. If they did a good job on it they would have put resist around the circumference of the coin as well otherwise that may show signs of etching also.

 

[mrbadexample]

Hmmm...I really can't tell. The lettering and area around the crown do look a bit grainy, but the higher points like the shoulder appear more consistent with the non-etched part. I guess that could mean the grainy texture has worn down through handling? There is some fairly heavy pitting in the portcullis too, but this is only in the area that would have been protected. If it is acid-etched, then I'd be thinking that the resist would have been in the form of some kind of tape wrapped round the coin as the edge has been protected in this area too. My next question is "why would someone do that?" 

 

[bhx7]

Don't think anyone would have done it to con or make money out of the penny. Think they have just done it to see what would happen or as an experiment of some kind.

As I said before its still a very unusual coin and a good curio to keep a hold of.

[mrbadexample]

I'm sorry, I'm too busy to reply because I'm now looking at USB microscopes so I can get a better look. 

[Nordle11]

1 hour ago, mrbadexample said:

I'm sorry, I'm too busy to reply because I'm now looking at USB microscopes so I can get a better look. 

Andonstar microscope. Cheap and does the job, cannot recommend it enough. Loads on eBay which is where I got mine. 

[mrbadexample]

1 hour ago, Nordle11 said:

Andonstar microscope. Cheap and does the job, cannot recommend it enough. Loads on eBay which is where I got mine. 

Ahhh, thanks. Appreciate the recommendation - it's been doing my head in looking at the myriad available.

[jelida]

I know this is a bit lateral but do you think it might have been used in electrolysis, as an anode or cathode for copper plating? the tape would have been used to hold the end of a wire against the coin, and where the coin was exposed to electrolyte, metal would have gone into solution. This might be a neat explanation.  Any scientists out there?

Jerry

[IanB]

I don't think that's likely. It would be easier to use a piece of copper as the anode than a coin also you would need to drill a hole in whatever was being used so that when it was wired up there was a good connection for the current to flow. Tape would not create a good connection and would lift off once the liquid got underneath it.

This coin was tapped probably with electrical tape as the resist and placed in nitric acid just long enough for the acid to start etching but not so long that the tape lifted and etched it all over.

[jelida]

Perhaps, but at least that would explain why it was done at all, for a purpose rather than pointlessly messing around with dangerously strong acids. A coin would be the most accessible source of metallic copper in the home, and electrical tape is waterproof and would certainly have made an adequate temporary connection; the electrolyte would have been easily available dilute cooking citric acid,vinegar or similar, and I think the area under the tape where there is darker linear pitting would suggest the wire contact point that would have reacted more aggressively when electrolyte did seep under the tape around the wire. I used to clean encrusted estuary found Roman coins by this very technique using my old Triang train controller for variable 12v and stainless steel electrode and crocodile clip, worked a treat!

Jerry

[mrbadexample]

Hopefully this will link to some better photos:

https://photos.google.com/album/AF1QipOeTuMiwcDLbv3q8YGwwPmVahlrK4nQq0HsLALL

[mrbadexample]

Is this 1947 penny of any interest?

 

 

[Nordle11]

3 hours ago, mrbadexample said:

Hopefully this will link to some better photos:

https://photos.google.com/album/AF1QipOeTuMiwcDLbv3q8YGwwPmVahlrK4nQq0HsLALL

Doesn't work for me?

Possible filled die for the 1947? Strange tail end on the 9 though, maybe PMD.

[mrbadexample]

https://goo.gl/photos/aTu1shXRxQ6h3oEJ7

How about that one?

[Nordle11]

Yes that works. One question - does the strip across the reverse match directly to the 2 'squares' on the reverse, so you could follow the outer lines and they meet up?

I don't think there is any example of a lamination flaw with such perfect shapes, but how it was done is the real question.

[mrbadexample]

11 minutes ago, Nordle11 said:

One question - does the strip across the reverse match directly to the 2 'squares' on the reverse, so you could follow the outer lines and they meet up?

Yes, they meet up. I'll see if I can get some kind of shot of the edge.

[mrbadexample]

[Nordle11]

I'm leaning toward a combo of Jerry's and Ian's thoughts, it has such likeness to the shape of having tape across it while the rest of it has been exposed to something.

[mrbadexample]

10 hours ago, Nordle11 said:

I'm leaning toward a combo of Jerry's and Ian's thoughts, it has such likeness to the shape of having tape across it while the rest of it has been exposed to something.

I can't argue - nothing else seems to make sense.

[Nordle11]

Added this one finally. Dot after N