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kallenwe
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| Posted: 21 May 2012 at 8:07pm | IP Logged
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Great question from an off-line observer. Seems he has a very valuable, ancient wrist watch. So special that it is stored in a very tight display box for protection. He also has a brand new, chrome tanned leather watch band still in its plastic shipping container. The question is: Would there be any harm in placing the new leather band in the display box with the delicate, old antique watch?
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DavidR
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| Posted: 22 May 2012 at 11:38am | IP Logged
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Most vegtannins in retannage are sulfited to the extent that SO2 is emmited slowly and is part of the "new-leather" smell. I suppose this will also insure that Cr plus 6 is not easily formed. Many fat-liquors will also generate small amounts of SO2 gas as well. Thus if the antique watch is just lightly gold plated rather than the "high quality" stuff, the pruducts of SO2 gas can easily tarnish thin electro-coated noble metal finishing, although solid stainless steel will not, as the chromium oxide coat is very untreactive hence there is no danger of getting Cr plus six from the elemental chrome components next to swetting skin, but lt probably depend on the alloying composition as well! Stainless steel against swetting skin might also be a source of Chrome six not much considered yet in the present hysteria! If mercury-amalgam dentistry materials would have been recently discovered, the sannitary authorities would probably not allow their usage today! Certainly lead weighted silk fabrics would not be allowed now-a-days!
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DavidR
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| Posted: 22 May 2012 at 9:42pm | IP Logged
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How about airing the watch-band for several weeks before installing and keeping some air circulation in the display case? Some activated carbon packets often accompaning certain pills and tablets could be included for additional safety and keen vigilance as well for the first sign of tarnishing!
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kallenwe
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What fumes cause the fog on automobile windows? Are "fog" specs for leather meaningful? Would formic acid be an issue?
Great thought about absorbant agents, ie maybe calcium chloride for moisture too as the leather may contain considerable moisture. But then again this may result in over drying the leather eventually. Any conservations in the crowd? Museums face these dilemmas regularly!
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kallenwe
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| Posted: 23 May 2012 at 5:30am | IP Logged
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Except for water, solvents should not be an issue as the watch is likely all metal parts. However, the trend to all aqueous finish coats may carry some additional risk.
Aldehydes ought to be of no consequence for several reasons, but are there other reactive volatiles in some watchband leathers? Lots of glue, cross-linkers and stitching aids!
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DavidR
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| Posted: 23 May 2012 at 11:19pm | IP Logged
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Actually unreacted aldehyde can generate acid when it displaces protons from charged aminos in leather. There are lots of stories of how the amunition in the Boer war between the British and the Dutch in South Africa was nearly lost by the British because the cartrige case were made from leather with unreacted aldehyde present and the acid formed as it tanned slowly generating acid that reacted badly and corroded the stored brass riflle cartriges. There are ways to protect leather from this by having inorganic amonium present and the aldehyde reacts with amonium to yield a very old and classical drug called urotropine that was once used to cure urinary infections as it slowly released aldehyde through the kidneys and urinary passages killing the microörganisms responsible for the infections. The drug is not employed anymore were doctors are sued for mal-practice because of the belived risks of formaldehyde effects, although formaldehyde is present in many "natural" foods such as apple peeilings! They worried about that before chrome was used.
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DavidR
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Oil origined fog on windshields are semi-volatile organic materials present in oils that condense on the glass after evaporating by heat from the upholstery. I would guess that a silicone treatment of the glass surface would change the game completely! Triphenylsilicon chloride treatment of a glass tube actually reverses the shape of the meniscous of water wetting the inside of glass tube. Very profound change of wetting properties that should also affect the fogging results on a flat piece of glass! At the end of WWII there was a plexiglass army-aircorps silicone winshield kit mentioned in classified accompaning literature that gave instructions how to make a small portion of the windshield absolutely transparent for all combat conditions which sold up through the 50's in surplus stores for a couple of dimes! I recall making the hard choice of buying such a kit, instead of two comic books, which was the way I learned by myself to read English!
Edited by DavidR on 25 May 2012 at 12:12am
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kallenwe
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| Posted: 27 May 2012 at 9:45am | IP Logged
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Could this "fog" eventually gum up the works in the watch?
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Leather Chemists : Leather Discussion
Topic: Harmful Gas from New Leather
