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I think I may have an old bobbin with white tin degredation. I had no idea what the metal wire around the bobbin body was but it sounds like it might be pewter. It feels rough on the surface of the metal. Is there anything I can do to clean it up. At the moment it is in a cabinet with other old bobbins I have acquired in the states. TIA.
Janice Blair, IL, US
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Dear Janice,
The pewter that is usually around the bobbin is not really describable as "wire" It would be a soft, solder like, material about 1/16 inch wide. Wire on bobbins is readily describable as wire, like fuse wire but usually brass.
OK, assuming that it is pewter, the answer is no! There is just nothing that you can do about it.
I am one of those terrible people that restore antique bobbins. (Shock, horror, Never buy a restored bobbin is the conventional wisdom, I can't understand why, pretty well all the antique furniture we buy is restored to a major or minor extent) Anyway. When I am faced with degraded pewter that is still in all the grooves, I return the bobbin to the lathe an very, very carefully sand or file or skew ( that is a turning tool) the absolute minimum off it to make it shine again. Do it carefully, DO NOT let it get hot or it will leave the bobbin.
Frankly, what I do does not stop the process, it does make the bobbin more aesthetically acceptable and feel better on the hands of the user.
If the pewter has gone from the bobbin, then I replace it with new pewter.
My main aim is to try and retain that unique feeling of a well used bobbin that only antique bobbins have, and of course make them look like the original.
Wire, if it is not broken can be cleaned. I try not to use cleaners or tarnish removers. Rather I use a soft brush and cloth to try and brush away the "gubbins" that is on the wire. It can be tedious, but I sit in front of the telly and do it, while my wife does her patchwork. ( Is she ever not doing her patchwork? I think she is as fanatical as you lace makers!)
If the wire is broken and is hanging around the bobbin like a loose spring, I remove it and put in new wire!
I would like to add, that if I sell a restored antique bobbin, I tell the purchaser that it is restored. I have also occasionally made a fairly accurate copy of an antique bobbin. I put my initials on those and tell the buyer that it is a copy.
This reminds me that I want to ask everyone if they have examples of how the old timers repaired their bobbins. I will put that in another email.
Brian
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I have today found out some more, but I can't think that I will discover any more, at least that I, a non scientist, could understand. The critical temperature is 13 deg C. It does not happen suddenly but occurs over a period of time. The pewter has to subjected to long long periods of sub 13 deg C, very easy in Europe! Now please accept that I dont really know about the science of this I am trying to understand and interpret it.. so here goes.
It appears that when the pewter catches "tin desease" some atoms change places, and in so doing crumbles the pewter and makes it swell. Help someone! I am quickly getting out of my depth.
I also read that the atoms ( I think) have different shapes in the two kinds of tin.
The other thing I learned was that you can tell how pure the tin is in its preprocessed state by bending it... it "Creaks" and feels like it is "Crumbling". Actually my pewter does that too.
If there are any scientists or metallurgists out there can you tell us more and or correct anything that I have said .
Brian
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The metal appears to change from what they call Grey Tin to White tin. Grey tin is apparently not attacked or is less likely to be attacked but when it changes to white tin then it becomes vulnerable. The organ pipes of Europe and the UK were badly effected by it and this is due to the temperature change year after year in the cold churches.( a piece of trivia).
I do not know the critical temperatures that changes it from grey to white but it is clear that the cold European nights turns the pewter into the white pewter and thence the powder type of tin disease that our bobbins show.
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More trivia about grey and white tin.
This was the supposed reason why Napoleon's attempt to conquor Russia failed. The cold Russian winter changed the tin buttons on his soldiers coats, and they crumbled off and left them exposed !
I'll have to find this out from my DH. But he's not availble ATM. Get back to you on that.
Jacky McDouall- Manchester, UK
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I have consulted my DH.
In pewter, being an alloy of tin, i.e. a mixture, it could be a little different to that of pure tin, but this is what happens to tin. Tin exists in three forms, depending on the temperature. This is called polymorphism (poly-many, morphism-shapes). At temperatures between 13 and 160 C, it is called White tin, and the atoms (think of them as little balls in this description) are packed closely together to form the metal. Hence, it is a dense metal, i.e. it is hard. Below 13 C the atoms rearrange to become more loosely packed (actually in the same configuration as diamond). This shows first as wart like structures on the surface, and eventually leads to the tin crumbling into a powder. This is called "tin pest", and is what happened to the buttons on Napoleon's soliders coats. I don't know how long this takes but it won't be very quick as all the atoms will have to move about - probably as long as it takes to march to Moscow from Paris ;-). Above 160 C, tin changes to another form called Brittle tin. Another form of packing for the atoms. But I don't think that will bother us :-).
Hope this answers some questions.
Jacky - Manchester, UK
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To Jackies DH,
Many thanks to you good sir. I knew that someone out there was an expert. I will now file that away for future use.
I have to say that I enjoyed the research, thanks to the library, a friend whom I am desparately trying to get to join Arachne and a second hand book store. I just read the page and did not buy the book. Shame on me! - Brian