Straightening Coins

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shingies pete
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Straightening Coins

Post by shingies pete » Thu Jan 06, 2011 5:46 pm

Hi all, i have a George 5th silver 3d which is in very nice condition other than the fact it is almost bent double.Any suggestions on a relatively safe way of straightening said coin? many thanks ,pete.
Last edited by shingies pete on Sat Mar 12, 2011 10:39 pm, edited 1 time in total.



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Re: STRAIGHTENING COINS

Post by PaulR » Thu Jan 06, 2011 7:00 pm

If its a milled coin the only way i can think of is in a vice but you must have something soft either side, i done it with a gold milled quarter guinea.
Tighten it a bit at a time.
It might be a love token so post it on here because if it is a love token i would leave it.
But if it goes wrong dont blame me lol =))

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Re: STRAIGHTENING COINS

Post by Tosherooni » Thu Jan 06, 2011 7:09 pm

Check this out from The Oldest Swinger. I haven't tried it myself but Paul got it to work on an 800 year old coin :)
Oldest Swinger wrote:Well here is my 1st Hammered of the yr and it turns out it not long cross afterall it a short cross. I straightened it by the anealing method IE I heated it up to cherry red then quenched it in cold water, then heated it up to cherry red again opening it up a little at a time before quenching before each aplication of heat. Once reasonably opened I heated it one last time and using a very small pin hammer gently tapped it on a block of smoothe wood to flatten. You be the judge see how it turned out remembering it was bent over double when I got it (I actually thought I had a cut quarter).

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Re: STRAIGHTENING COINS

Post by Fusion » Thu Jan 06, 2011 9:10 pm

I've successfully straightened a severely bent silver coin using the annealing method, after you've bent it a bit, re-anneal it, as the bending work-hardens the metal, then repeat as neccessary. Dont forget this softens the whole coin, so the surface features are vulnerable to clumsy straightening methods. Google-ing 'straightening bent silver coins' or similar, should lead you to details of the method.
There was a forum thread on this subject a couple of months ago. I've also seen a link, possibly on the Colchester MD club's website, to a silversmith who offers straightening services, prices seemed reasonable.Hope this helps.
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Re: STRAIGHTENING COINS

Post by Oldest Swinger » Thu Jan 06, 2011 9:15 pm

Can you see the date on the coin as it could be one of 2 different metal compasitions. Coins after 1920 (during George V reign) where only 50% silver and this could make a difference when using the anealing method.

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Re: Straightening Coins

Post by hammyman » Thu Jan 06, 2011 10:29 pm

Oldest Swinger wrote:Can you see the date on the coin as it could be one of 2 different metal compasitions. Coins after 1920 (during George V reign) where only 50% silver and this could make a difference when using the anealing method.

Paul
Funnily enough Paul there are .925 coins and .500 coins all dated 1920 (six pences and three pences)
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Re: Straightening Coins

Post by shingies pete » Thu Jan 06, 2011 10:37 pm

Many thanks for suggestions,coin is dated 1914.Will check out you-tube for subject matter and let you know how i get on thanks again ,pete.

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Re: STRAIGHTENING COINS

Post by Wansdyke44 » Fri Jan 07, 2011 8:49 am

PaulR wrote:If its a milled coin the only way i can think of is in a vice but you must have something soft either side, i done it with a gold milled quarter guinea.
Tighten it a bit at a time.
It might be a love token so post it on here because if it is a love token i would leave it.
But if it goes wrong dont blame me lol =))
Just out of curiousity, and because I don't know the answer... was the practice of bending coins into "love token" still practised in the early 20th Century? I've always assumed it was an older custom?
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Re: Straightening Coins

Post by Oldest Swinger » Fri Jan 07, 2011 2:53 pm

Old Jeffers wrote:I tried this kneeling on coins to straighten them out....my knees are killing me now! :))

Heat treating the coins is really the only satisfactory method to (fairly) safely
straighten a coin.
Silly gugga since when you been called Anne. It only works if someone called Anne does it m8.

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Re: Straightening Coins

Post by Blade916 » Sat Jan 08, 2011 10:37 pm

hi ive been told you can straighten bent coins by putting them in boiling water and then pressing gently on them with a glass or something heavy, do it a few times until its straighter, i had my lisy 1st hammered done in this way by a friend and it worked well !! hope it helps :)
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Re: Straightening Coins

Post by parky844 » Sun Jan 09, 2011 6:05 am

I put bent hammered between two bits of soft pine and give it a hefty whack with a hammer ,this has always worked for me,all done in one go in seconds,dont think this would work on anything thicker than a hammered tho.

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Re: Straightening Coins

Post by dep1699 » Thu Aug 23, 2018 2:02 pm

Blade916 wrote:
Sat Jan 08, 2011 10:37 pm
hi ive been told you can straighten bent coins by putting them in boiling water and then pressing gently on them with a glass or something heavy, do it a few times until its straighter, i had my lisy 1st hammered done in this way by a friend and it worked well !! hope it helps :)
Thanks, I have just straighten an EdwardI penny with this method. You just need to be gentle and keep boiling it

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Re: Straightening Coins

Post by targets » Thu Aug 23, 2018 4:40 pm

what they dont say is when you anneal silver the base metals come to the surface so its needs pickling in acid otherwise it takes on a copper appearance..

1. Firescale Definitions

“As studio jewelers the term “firescale” on silver – has become ingrained in us. I would like to start with a simple overview of what is involved when we talk about “firescale”: Most jewelers believe, that copper oxides do remain below the surface of silver-copper alloys after annealing and pickling and will haunt them in the polishing stage. This is not correct. Since nobody seemed to differentiate between fine silver surface layers, created while pickling and the base silver alloy, we have this tremendous confusion and fear amongst jewelers. The word “Firescale” is used for at least two very different metal behaviors and appearances, reaching from mild polishing problems to extreme conditions that result in the breakdown of a silver alloy’s cohesiveness. Let’s keep it simple while looking at basic facts and processes used in our studios.”

Many shape changes; rolling, drawing, bending and forging harden the inner crystal structure of our alloy.
Annealing is essential to line up the crystals to soften the inner consistency of our metal in order to continue working.
As a side effect of annealing and soldering, the surface layer of our metal transforms, creating the conditions for discoloration to occur.

Sterling and Oxides
While heating our work, first reddish, then grayish and later black oxides appear on the surface as a result of the 7.5 % copper content (added for strength in Sterling silver). As a consequence, we need to acid treat (or “pickle”) our silver work. During “pickling”, copper oxides are dissolved and leached out from the silver alloy’s surface, leaving the piece with a matte white, spongy, pure silver top layer. Multiple annealing or soldering will increase the layers of pure silver. It is important to understand that these layers will finally loose all of their copper content and cannot oxidize anymore! In fact, these spongy silver layers are the cause of our polishing difficulties. It is important to know that the Sterling metal below remains unaffected by oxides under regular studio conditions. The base can be polished beautifully if the fine silver is removed! This is not the same as in the extreme case: where the Deep Layer Oxidation is a consequence of severe overheating. In Deep Layer Oxidation the oxides proceed into the alloys interior and polishing becomes futile. “Firescale” seems to have become synonymous with troubles and blamed for all of the above.
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Re: Straightening Coins

Post by Rah7265 » Thu Aug 23, 2018 6:25 pm

I managed to straighten out a silver hammered that was curled up around the edge by heating in in boiling water (I didn’t dare put a flame on it) and gently rolling it out with a rolling pin against a wooden bread board.

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Re: Straightening Coins

Post by Ten pence! » Thu Aug 23, 2018 6:43 pm

Boiling water is nowhere near hot enough to anneal silver! Silver needs to be heated to a very light dull pink and then quenched in cold water to anneal it, this is typically around 400-450c, you got lucky with that particular coin!

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Re: Straightening Coins

Post by thefiggis » Thu Aug 23, 2018 7:20 pm

Ten pence! wrote:
Thu Aug 23, 2018 6:43 pm
this is typically around 400-450c
Hotter than that, isn't it? 590 - 650C, but quite right - boiling water is nowhere near hot enough to soften it let alone alter the structure from what I've researched.
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Re: Straightening Coins

Post by dep1699 » Thu Aug 23, 2018 9:06 pm

thefiggis wrote:
Thu Aug 23, 2018 7:20 pm
Ten pence! wrote:
Thu Aug 23, 2018 6:43 pm
this is typically around 400-450c
Hotter than that, isn't it? 590 - 650C, but quite right - boiling water is nowhere near hot enough to soften it let alone alter the structure from what I've researched.
You maybe are right. But it was actually soft and bendable and this is the result
IMG_20180823_154325-781x701.jpg
IMG_20180823_155920-781x763.jpg
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Re: Straightening Coins

Post by thefiggis » Thu Aug 23, 2018 9:30 pm

Sure, you can get away with it and I have to say I've done much the same with coins which are slightly bent. How out-of-shape was yours originally?

Personally, I wouldn't dream of anything other than full annealing with a coin which is more than slightly curved. As was explained to me, when a coin is made it's a certain shape (flat). Then over time it gets bent - not the shape it was made to be. What you have to do is persuade it back to its original shape while maintaining its integrity and you can only maintain this integrity by annealment. Once you have it back to its original form a final annealment cements it in shape, all molecules happy and having a beer.

If you don't anneal you're asking it to change shape twice (bent then straightened) and sometimes it will object and snap.

At the end of the day it's your coin and you do as you think fit. There are many who use boiling water but quite frankly I think it's useless and if the coin goes back to shape it would equally have done so without boiling water. Even then, without annealment the molecules are permanently under stress and need medication to prevent them from failing along the fault line at any time in the future.
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Re: Straightening Coins

Post by f8met » Thu Aug 23, 2018 9:40 pm

I often do it in the field, press it gently against the spade which straigtens most hammered. Too bent or cracked then don't and some silver alloys won't take it. The sterling imitation I have I broke as I didn't realise it was more brittle than pure silver. And looking more closely at the gold hammered I straighted I was very lucky.

I would say the one put in boiling water would have straightened anyway.
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Re: Straightening Coins

Post by CTX_Phil » Thu Aug 23, 2018 11:19 pm

f8met wrote:
Thu Aug 23, 2018 9:40 pm
I often do it in the field
Least I'm not the only one ;)

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Re: Straightening Coins

Post by f8met » Fri Aug 24, 2018 12:03 am

Don't do as I do lol
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Re: Straightening Coins

Post by dep1699 » Fri Aug 24, 2018 12:33 am

thefiggis wrote:
Thu Aug 23, 2018 9:30 pm
Sure, you can get away with it and I have to say I've done much the same with coins which are slightly bent. How out-of-shape was yours originally?

Personally, I wouldn't dream of anything other than full annealing with a coin which is more than slightly curved. As was explained to me, when a coin is made it's a certain shape (flat). Then over time it gets bent - not the shape it was made to be. What you have to do is persuade it back to its original shape while maintaining its integrity and you can only maintain this integrity by annealment. Once you have it back to its original form a final annealment cements it in shape, all molecules happy and having a beer.

If you don't anneal you're asking it to change shape twice (bent then straightened) and sometimes it will object and snap.

At the end of the day it's your coin and you do as you think fit. There are many who use boiling water but quite frankly I think it's useless and if the coin goes back to shape it would equally have done so without boiling water. Even then, without annealment the molecules are permanently under stress and need medication to prevent them from failing along the fault line at any time in the future.
Ok Maybe I was just lucky. I'll buy a blow torch :-)

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Re: Straightening Coins

Post by fred » Fri Aug 24, 2018 8:03 am

A George V silver 3d bent almost double would have to have been done deliberately. Even if you straighten it out it will show a crease so will never be valuable or anything like as interesting as it is bent double. I would regard it's condition as reflecting it's history and leave it well alone. :D
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Re: Straightening Coins

Post by roadwarriormax » Fri Aug 24, 2018 8:17 am

i,ve worked with silver over many years, making rings and bracelets and necklaces .if your going to try and straighten an old silver coin ,you will need to anneal it .and hot water from kettle won't do anything ,you will need to heat it up using a flame (small blowtorch ) and then quenched in water ,this will make silver soft again, if you try and straighten without annealing it ,chances are, it will break .espcecially with old silver ,there,s a good reason why some many old silver coins have cracks in them . heat the coin up to a dull orange .then quenched in water,slowly start to straighten the coin .bit by bit, annealing again, after every small adjustment, dont be greedy when trying to straighten it , if it takes 6 goes, then it takes 6 goes. use a piece of softwood. , as other people have said , the whole coin will become softer, so take it slow . it will pay off taking your time . rushing it will only mess it up .
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Re: Straightening Coins

Post by JBM » Fri Aug 24, 2018 8:23 am

While we all prefer to find undamaged coins trying to straighten one can devalue its potential value.

None us will ever know what going to pop up next and and in some rare cases we could be talking of many thousands of pounds.

Any find coin is is what it is unlesS you or your dependents intend to keep the coin in question.

Yes one day it could happen to you just as it has to a few others.

Iam speaking from experience so take care.

Happy Hunting,

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