Straightening silver coins

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Bors
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Re: Straightening silver coins

Post by Bors »

PinkFloyd wrote:
Tue Feb 11, 2020 12:16 pm
I’ve done a fair few doubled over flat and they’ve never cracked matey ::g
If your careful, take a bit of time and even the real old generation your in could do it :D ::g
The beauty of hearing this is Paul is ,one day sooner than you probably think YOUR going to join the club yourself IF you make it, so I wouldn`t imagine even a Peter Pan-like thou, is going to escape its clutches =))
Can you see it ????? The boney finger is beckoning you right this minute,as we speak. =))


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Re: Straightening silver coins

Post by targets »

old silver sheet becomes crystalised in the soil compared with new silver sheet which can be annealed a few times but they all need pickling in acid afterwards as they become fire scaled ,each coin will vary as to what they can take
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Re: Straightening silver coins

Post by Easylife »

thefiggis wrote:
Sun Feb 09, 2020 9:49 pm
As with many aspects of cleaning or "improving" coins, the subject of straightening a bent one has many opinions ranging from "never!" to "of course, why not?".
FWIW, with a bent hammered silver, I first give it a steady squeeze between the fingers, if it gives then it will straighten cold. If it resists then it will require annealing - simples! Any bent coin first requires some close scrutiny to evaluate it as to the best course of remedial action. For most my method is quite similar to others. In low light I heat using a blow torch just until it glows a dull red, but know that just a very few seconds more and it would be a much hotter bright red, though it doesn't really seem to make much difference. The idea of annealing is to alter the metal structure so as to make it more pliable, so after it has reached it's optimal temperature it does not matter whether it is hot or cold before straightening. Anyways - my cold press method is generally between two bits of hardwood in a vice cos I like 'em nice and flat! But I also still follow a great tip from SS47 and use various sized timber rollers. On say a folded over coin starting with a real small roller to ease the crease, re- annealing and slowly increasing roller size, and so on, finishing with one of about 1 inch. Though I guess a wooden spoon would be okay if just a bit bent. If the coin is cracked then try to roll at an angle so as not to stress it further. This method also works with copper/alloy finds though they prefer a good glow before easment for best results.
I like quick results so a blast of metal polish on the high spots is normally all that is needed. It maybe just takes 2 or 3 mins per coin or less if batched together. But of course it is always best if possible to identify the coin first to establish whether it might have any great value and then act accordingly. Bent coins just don't look very asthetically pleasing but can be quite transformed into a little treasure just by a couple of minutes straightening. I'd love to have a go at a gold one but just need to find one first - maybe one day? :))
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Re: Straightening silver coins

Post by thefiggis »

Some great tips and advice coming through, so thanks so much for that ::g

Seems like we're all doing pretty much the same thing but it's always good to refine our technique and gain knowledge from the experience of others.

Removing heavy firescale through pickling hasn't been mentioned so far. Anyone tried it, or are you happy to put up with a bit of a blush on the coin?
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Re: Straightening silver coins

Post by Bors »

Fusion wrote:
Tue Feb 11, 2020 12:37 pm
I also think Bors is too pessimistic. I've perfectly flattened some bent double coins, one with two massive cracks in it.

Multiple repeated annealing/straightening sessions is the key. People perhaps don't understand that bending many metals, including silver, causes it to harden - it's known as work-hardening. So every time you straighten a bent coin a little, it needs re-softening, so it can be bent more. It's not just the initial annealing procedure that's important.
I may be getting slightly misunderstood here .
I`m not saying they cannot be straightened out, as thats the easy bit . What I am saying is once a Coin has been bent as far over as "doubled over to almost flat " it's pretty much impossible to straighten them out >>>> (without cracking the coin) thats the bit I was getting at & God knows I`ve tried and tried ,but never succeeded in doing it without it resulting in a cracked coin for my attempts, and you mightn`t even think it's not cracked, but you soon see it is, when you inspect the coin with a loupe.
Don`t forget that coin has been under the ground being going through a sort of annealing by warm weather soil ,and then next frozen to probably freezing point come wintertime comes and that happened probably multi hundreds of times over centuries and the constant temperature changes without doubt will have taken its toll on the metal of the coin over the centuries.
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