1945 Penny - Thin flan

[Accumulator 52]

I'd be interested to have your views on this penny. It's wafer thin and weighs 6.06g. Maybe a halfpenny planchet?

[Rob 3,152]

I'd be interested to have your views on this penny. It's wafer thin and weighs 6.06g. Maybe a halfpenny planchet?

Looks to be a wrong flan rather than a chemically induced low weight. The teeth striations on the obverse go all the way to the legend which could be explained by the flan spreading? But there isn't any corresponding stretching in the legend. Odd.

What dimensions are the portrait and is the legend at the right diameter? The correct weight for a 1/2d flan is about 5.6-5.7g. Is the overall diameter correct?

Edited December 24, 2011 by Rob

[Peckris 579]

I'd be interested to have your views on this penny. It's wafer thin and weighs 6.06g. Maybe a halfpenny planchet?

That's a classic case of acid bath (post-production, of course). Typically all the detail remains in a semi-ghostly form, but the planchet goes very very thin.

Edited December 24, 2011 by Peckris

[davidrj 194]

I'd be interested to have your views on this penny. It's wafer thin and weighs 6.06g. Maybe a halfpenny planchet?

That's a classic case of acid bath (post-production, of course). Typically all the detail remains in a semi-ghostly form, but the planchet goes very very thin.

Hmm, not sure - Stress lines on obverse might indicate a split flan

[Accumulator 52]

I'd be interested to have your views on this penny. It's wafer thin and weighs 6.06g. Maybe a halfpenny planchet?

That's a classic case of acid bath (post-production, of course). Typically all the detail remains in a semi-ghostly form, but the planchet goes very very thin.

I've never actually seen a coin that's been in an acid bath. I would have expected it to be surface pitted though and also not to have the extended teeth, as Rob points out. Would this just be someone having fun with H2SO4? I ought to get some acid and try it for comparison.

Rob, the portrait and legend are all correct but the overall diameter is slightly less, with the edges almost ending at a point, suggesting there wasn't sufficient metal.

[Peckris 579]

I'd be interested to have your views on this penny. It's wafer thin and weighs 6.06g. Maybe a halfpenny planchet?

That's a classic case of acid bath (post-production, of course). Typically all the detail remains in a semi-ghostly form, but the planchet goes very very thin.

I've never actually seen a coin that's been in an acid bath. I would have expected it to be surface pitted though and also not to have the extended teeth, as Rob points out. Would this just be someone having fun with H2SO4? I ought to get some acid and try it for comparison.

Rob, the portrait and legend are all correct but the overall diameter is slightly less, with the edges almost ending at a point, suggesting there wasn't sufficient metal.

Surface pitting would occur with minor acid spills - localised damage. Where a coin has been immersed completely for a while in an acid bath, the metal dissolves, though due to the characteristic nature of strikes, the surface detail is not the first to go; I'm not sure why. I think the 'extended teeth' MAY be due to striking stresses in the original normal coin, which would be beneath the surface and hence invisible under normal circumstances (but that part is just an educated guess). I'd be 90% confident of the acid bath hypothesis though.

[Coinery 1,153]

Total Sherlock Holmes here, as I know not a jot about this scenario. However, in support of the acid theory, the coin looks like it may have been placed reverse side down in a flat-bottomed vessel, which has protected the raised surfaces of the reverse from the degree of erosion that looks to have ravaged the obverse. The acid would continually be neutralising itself underneath the fine gap between the reverse and vessel bottom through its ongoing reaction with the material. Whereas the obverse would have been exposed to the rip-roaring effect of full strength acid bearing down on it throughout.

Doesn't explain everything, but it's food for thought!

[azda 979]

The elongated teeth on the OBV (which are going into the legend also) would suggest that the flan was'nt quite big enough when being minted and spread the teeth outwards.

[Gary D 76]

I've a couple of these of different dates, definitly an acid bath job.

[Peckris 579]

I've a couple of these of different dates, definitly an acid bath job.

Yes - I have a 1929 shilling like this. Once I'd learned it was acid, I can now recognise them almost instantly.

[azda 979]

I've a couple of these of different dates, definitly an acid bath job.

Yes - I have a 1929 shilling like this. Once I'd learned it was acid, I can now recognise them almost instantly.

I thought acid erodes and not stretch metal?

[Peckris 579]

I've a couple of these of different dates, definitly an acid bath job.

Yes - I have a 1929 shilling like this. Once I'd learned it was acid, I can now recognise them almost instantly.

I thought acid erodes and not stretch metal?

Yes. But the elongated teeth may be underlying stress patterns from the strike which are normally invisible but which have been uncovered by the metal erosion.

[VickySilver 830]

I too will weigh in on this: acid bath, and have a couple as well.

[Coinery 1,153]

The 'tooth' between D & G, alongside the colon, on the obverse, stretches well beyond the legend, and breaches the field, without the slightest distortion to the lettering and, as Rob suggested at the start of the thread, seems a little odd if this is purported to be a stretched flan. There seems to be no other rational explanation for this coin, scientifically speaking (outside of any suggestion that there was a die cut with teeth extending beyond the legend), other than to say that the extended teeth were exposed by erosion. It's not inconceivable, we already know that metal becomes harder when stressed and compressed - this makes perfect sense then to me that the compression forces at the edge of the coin, forming the teeth, would penetrate deep into the blank, never to be seen again until the softer, unstressed metal, is dissolved first by some 'chemical process or other.'

All humbly theoretical of course!

[Peckris 579]

The 'tooth' between D & G, alongside the colon, on the obverse, stretches well beyond the legend, and breaches the field, without the slightest distortion to the lettering and, as Rob suggested at the start of the thread, seems a little odd if this is purported to be a stretched flan. There seems to be no other rational explanation for this coin, scientifically speaking (outside of any suggestion that there was a die cut with teeth extending beyond the legend), other than to say that the extended teeth were exposed by erosion. It's not inconceivable, we already know that metal becomes harder when stressed and compressed - this makes perfect sense then to me that the compression forces at the edge of the coin, forming the teeth, would penetrate deep into the blank, never to be seen again until the softer, unstressed metal, is dissolved first by some 'chemical process or other.'

All humbly theoretical of course!

You don't seem to have read any of my posts? I suggested that acid has eroded away the metal to such an extent that the underlying stress patterns caused by the teeth area of the strike (normally invisible) have been exposed to view.

[Accumulator 52]

The 'tooth' between D & G, alongside the colon, on the obverse, stretches well beyond the legend, and breaches the field, without the slightest distortion to the lettering and, as Rob suggested at the start of the thread, seems a little odd if this is purported to be a stretched flan. There seems to be no other rational explanation for this coin, scientifically speaking (outside of any suggestion that there was a die cut with teeth extending beyond the legend), other than to say that the extended teeth were exposed by erosion. It's not inconceivable, we already know that metal becomes harder when stressed and compressed - this makes perfect sense then to me that the compression forces at the edge of the coin, forming the teeth, would penetrate deep into the blank, never to be seen again until the softer, unstressed metal, is dissolved first by some 'chemical process or other.'

All humbly theoretical of course!

You don't seem to have read any of my posts? I suggested that acid has eroded away the metal to such an extent that the underlying stress patterns caused by the teeth area of the strike (normally invisible) have been exposed to view.

I'm going with your acid theory Peckris. If I had some concentrated H2SO4 laying around I'd throw a penny in to see if I could replicate the effect on another coin.

[Peckris 579]

Here is my 1929 shilling. As you can see, ALL the detail is present (unlike a normal worn coin) but in a very faded and ghostly form. I'd guess that the original was at least VF when it was 'acid bathed'. One thing you can't see is the wafer thin-ness of it, nor the milling still visible on what's left of the edge. What you can see however, is that the rim has all but disappeared on both faces, which seems to be one of the areas of metal that goes first.

Edited December 28, 2011 by Peckris

[Gollum 2]

Here is my 1929 shilling. As you can see, ALL the detail is present (unlike a normal worn coin) but in a very faded and ghostly form. I'd guess that the original was at least VF when it was 'acid bathed'. One thing you can't see is the wafer thin-ness of it, nor the milling still visible on what's left of the edge. What you can see however, is that the rim has all but disappeared on both faces, which seems to be one of the areas of metal that goes first.

I can only see the obverse and reverse, that gives me no clue as to how thin it is. could we have a side view ?.

[DaveG38 405]

The 'tooth' between D & G, alongside the colon, on the obverse, stretches well beyond the legend, and breaches the field, without the slightest distortion to the lettering and, as Rob suggested at the start of the thread, seems a little odd if this is purported to be a stretched flan. There seems to be no other rational explanation for this coin, scientifically speaking (outside of any suggestion that there was a die cut with teeth extending beyond the legend), other than to say that the extended teeth were exposed by erosion. It's not inconceivable, we already know that metal becomes harder when stressed and compressed - this makes perfect sense then to me that the compression forces at the edge of the coin, forming the teeth, would penetrate deep into the blank, never to be seen again until the softer, unstressed metal, is dissolved first by some 'chemical process or other.'

All humbly theoretical of course!

You don't seem to have read any of my posts? I suggested that acid has eroded away the metal to such an extent that the underlying stress patterns caused by the teeth area of the strike (normally invisible) have been exposed to view.

I'm going with your acid theory Peckris. If I had some concentrated H2SO4 laying around I'd throw a penny in to see if I could replicate the effect on another coin.

You'd need to boil it to get the reaction going. Copper metal doesn't react with either dilute or cold concentrated sulphuric acid. Better to use dilute nitric which will strip it back in no time. Sulphuric will react with surface layer of oxide or sulphide though, giving a nice shiney surface finish.

[Coinery 1,153]

The 'tooth' between D & G, alongside the colon, on the obverse, stretches well beyond the legend, and breaches the field, without the slightest distortion to the lettering and, as Rob suggested at the start of the thread, seems a little odd if this is purported to be a stretched flan. There seems to be no other rational explanation for this coin, scientifically speaking (outside of any suggestion that there was a die cut with teeth extending beyond the legend), other than to say that the extended teeth were exposed by erosion. It's not inconceivable, we already know that metal becomes harder when stressed and compressed - this makes perfect sense then to me that the compression forces at the edge of the coin, forming the teeth, would penetrate deep into the blank, never to be seen again until the softer, unstressed metal, is dissolved first by some 'chemical process or other.'

All humbly theoretical of course!

You don't seem to have read any of my posts? I suggested that acid has eroded away the metal to such an extent that the underlying stress patterns caused by the teeth area of the strike (normally invisible) have been exposed to view.

I concur 100% with your posts and theory! My thread echos exactly what you have been saying, mine's just a proposed idea of the processes involved!

[Peckris 579]

Here is my 1929 shilling. As you can see, ALL the detail is present (unlike a normal worn coin) but in a very faded and ghostly form. I'd guess that the original was at least VF when it was 'acid bathed'. One thing you can't see is the wafer thin-ness of it, nor the milling still visible on what's left of the edge. What you can see however, is that the rim has all but disappeared on both faces, which seems to be one of the areas of metal that goes first.

I can only see the obverse and reverse, that gives me no clue as to how thin it is. could we have a side view ?.

Unfortunately not - I only got my scanner working with great difficulty and there is NO way I can scan an edge!!

The 'tooth' between D & G, alongside the colon, on the obverse, stretches well beyond the legend, and breaches the field, without the slightest distortion to the lettering and, as Rob suggested at the start of the thread, seems a little odd if this is purported to be a stretched flan. There seems to be no other rational explanation for this coin, scientifically speaking (outside of any suggestion that there was a die cut with teeth extending beyond the legend), other than to say that the extended teeth were exposed by erosion. It's not inconceivable, we already know that metal becomes harder when stressed and compressed - this makes perfect sense then to me that the compression forces at the edge of the coin, forming the teeth, would penetrate deep into the blank, never to be seen again until the softer, unstressed metal, is dissolved first by some 'chemical process or other.'

All humbly theoretical of course!

You don't seem to have read any of my posts? I suggested that acid has eroded away the metal to such an extent that the underlying stress patterns caused by the teeth area of the strike (normally invisible) have been exposed to view.

I concur 100% with your posts and theory! My thread echos exactly what you have been saying, mine's just a proposed idea of the processes involved!

Sorry, you're quite right. It was actually me that didn't read the post carefully enough!