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Silver Blueing
I lost my access to usenet so I kind of lost track of this group.
As some of you may remember, I made some hand forged flatware a few years ago. details: http://schmidling.com/silver.htm We use the knife and fork at dinner every day and it gets washed with soap and a Scotchbrite sponge so it stays clean and bright. In the past few months we have noticed that the tines show a blue color reminiscent of the tempering stages while hand forging. It takes a bit of an effort to get rid of but in a few days it comes back again but only the tines. It has been at least 5 years since I made these but the tines never looked any different from the rest of the fork and this problem just started a few months ago. Any ideas? Jack Schmidling Astronomy, Beer, Cheese, Fiber, Gems, Nature, Radio, Sheep, Sausage, Silver http://schmidling.com |
Silver Blueing
Yep sulphur. It's a problem with modern society. There's not much that
you can do about it. I suppose you could wash your cutlery in a natural soap and hot water. Regards Charles Jack Schmidling wrote: I lost my access to usenet so I kind of lost track of this group. As some of you may remember, I made some hand forged flatware a few years ago. details: http://schmidling.com/silver.htm We use the knife and fork at dinner every day and it gets washed with soap and a Scotchbrite sponge so it stays clean and bright. In the past few months we have noticed that the tines show a blue color reminiscent of the tempering stages while hand forging. It takes a bit of an effort to get rid of but in a few days it comes back again but only the tines. It has been at least 5 years since I made these but the tines never looked any different from the rest of the fork and this problem just started a few months ago. Any ideas? Jack Schmidling Astronomy, Beer, Cheese, Fiber, Gems, Nature, Radio, Sheep, Sausage, Silver http://schmidling.com |
Silver Blueing
Jack Schmidling wrote:
I lost my access to usenet so I kind of lost track of this group. As some of you may remember, I made some hand forged flatware a few years ago. details: http://schmidling.com/silver.htm We use the knife and fork at dinner every day and it gets washed with soap and a Scotchbrite sponge so it stays clean and bright. In the past few months we have noticed that the tines show a blue color reminiscent of the tempering stages while hand forging. It takes a bit of an effort to get rid of but in a few days it comes back again but only the tines. It has been at least 5 years since I made these but the tines never looked any different from the rest of the fork and this problem just started a few months ago. Any ideas? Jack Schmidling Astronomy, Beer, Cheese, Fiber, Gems, Nature, Radio, Sheep, Sausage, Silver http://schmidling.com Welcome back, Now, im guessing here, but something in your lifestyle has changed. It could be the soap tho most folk dont use soap as is generally known to do the dishes, they use a detergent, tho you might be tho odd one that uses traditional soap. Or you may have changed the type of heating you have in your home. There have been cases where folk have gone from a coal based domestic heat source to gas. This has caused silver ware to discolour much more quickly, due to the sulphur in the gas combustion by products. or more fundamental still, youve changed your water supply from say a local spring or rain water, to a mains or municipal supply. Or youve started to use your cutlery on a different food , on a regular basis. for example you might have started eating a food that has a tarnishing effect. Or even your now downwind from some other contaminant caused by another neibour or business, even many miles away. Have a think and see if you can find something along the linesmentioned above. Hope you keeping well, regards from dorset UK. |
Silver Blueing
First of all, some comments on the group.
Glad to see a few names here that I recognize from the past. I tend to hop around from hobby to hobby like a jack in the box and have been obsessed with amateur radio for the past several years. I have been a ham since 1955 but out more than in. I was saddened when I lost usenet access but got to liking Yahoo Groups a lot. It appears now that Google has enabled an email option for usenet access but I have not quite figured it out as there is so little traffic on this list. Anyway, thanks for the thoughts on my blueing but I do not think it is a simple matter of tarnish for the simple reason that it only appears on the tines. My instinct says that tarnish is a surface phenomenon and should appear all over the piece. As the tines are the thinnest part of the piece, I suspect it is a heat related issue. When tempering during forging, the tines always got hotter, faster than the rest of the piece and may have left a latent image of the blue stage on the tines. Why it has just begun to show up is the real mystery. I am thinking that somehow annealing it again may be the cure but need some moral support before venturing back into this. Jack |
Silver Blueing
On Tue, 16 Feb 2010 21:13:54 -0800, in rec.crafts.jewelry Jack Schmidling
wrote: First of all, some comments on the group. Glad to see a few names here that I recognize from the past. I tend to hop around from hobby to hobby like a jack in the box and have been obsessed with amateur radio for the past several years. I have been a ham since 1955 but out more than in. The group's gotten slower and slower over the years, as more and more of the discussion moved to the much busier Orchid mail list, hosted on Ganoksin.com (where you might wish to also post this question) But I'm still moderating it, and a few of the other longtime members seem to still chime in when someone has a question. I was saddened when I lost usenet access but got to liking Yahoo Groups a lot. It appears now that Google has enabled an email option for usenet access but I have not quite figured it out as there is so little traffic on this list. If you've got web access, then you have access to this newsgroup through Google groups. While rec.crafts.jewelry is not a Google group, but rather part of the older and wider usenet structure, Google includes access to all the text based usenet groups right alongside their Google-only hosted groups. You can read and post to the group right from the Google Groups web site. It sometimes is a bit slower in getting messages to me that are direct news servers, but most of the time, you won't notice the difference. The Google site also offers a complete archive of the group, going back pretty much to it's inception, prior to it's being a moderated group. Or almost that far, I think... Anyway, thanks for the thoughts on my blueing but I do not think it is a simple matter of tarnish for the simple reason that it only appears on the tines. My instinct says that tarnish is a surface phenomenon and should appear all over the piece. Yes, but tarnish is the conversion of silver and copper to silver and copper sulphides (Not oxides, which you have to deal with when heating the metal. Tarnish normally is sulphides). To a degree, it's influenced by the amount of copper in the surface, as well as by the amount of copper oxides either present, or not present, also at the surface and in the surface layers. This brings us to the subject of fire stain and fire scale in sterling silver. When you heat sterling in air, without the right flux coating protection, the copper at the surface immediately oxidizes to the black copper oxide, giving a black surface (fire scale). This is removed by pickling, leaving a white silver surface which has little if any copper left, right at the surface. However, at annealing temperatures, silver is fairly permiable to oxygen, which penetrates a bit into the surface if it can, depending on lenth of heating and temperature. So under that thin surface skin of white frosty fine silver, there begins a layer where oxygen has reached, oxidizing copper that's there, to the red oxide of copper (the black is two oxygen atoms per copper, while the red is one). This layer can penetrate some surprising and annoying distance into the surface. Because there's only 7.5 percent copper in silver, the layer is not red, but rather faintly pinkish/cream colored. Different, in any case, from clean unoxidized sterling silver. Ordinarily, it's not noticed much, but when polished, at the rouge step, clean silver brings up a wonderful deep rich polish, while the areas with imbedded oxide (this is called fire stain) don't polish quite as well. Annoying, and it can mess up a finish, so then you have to remove that layer. Anyway, on your fork, you've got a cast handle. No doubt it got heated some during working, as well as just being hot during the cool down phase of casting. If you did little to it beyond lightly finishing it up, as might be the case if you were trying to retain cast pattern, you might have a surface somewhat depleted in copper. But if you didn't repeatedly heat that portion while annealing to forge the fork, and if you also did not protect the tine portion from fire scale/fire stain formation during annealing, then the tine portion of the metal may have more imbedded copper oxide, ie a thicker layer of fire stain within it. And depending on whether you cut the tines last, or before the last annealing, the inside edges of the cut times, which might have recieved less filing and sanding than the outer smooth surfaces, might also differ in oxide content. All these factors will change the way the surface forms tarnish. So it's quite possilble that only the tines tarnish, if the main portion of the fork handle has less copper at the surface. Silver itself also forms the sulphides, but does so much more slowly than does copper, so there can be a distinct difference in tarnish between copper depleted areas, normal clean sterling areas, and fire stained areas. \ As the tines are the thinnest part of the piece, I suspect it is a heat related issue. When tempering during forging, the tines always got hotter, faster than the rest of the piece and may have left a latent image of the blue stage on the tines. Why it has just begun to show up is the real mystery. Latent image? Blue stage? Ain't rilly no such things. :-) The hotter tines might have grown a larger crystal structure if over annealed. But annealing and heating tends to homogeonize the metal structure, except for the bit about oxygen penetrating as noted above. Oh, and heating to well below annealing temp (about 700F) for longer times to age harden the metal (which is NOT called tempering, by the way. Tempering is a process pretty much unique to ferrous metals) That causes a migration of copper within silver crystals to the crystal boundaries, which makes the crystal boundaries less flexible, thus hardening the metal some. The degree to which this works will also be affected by existing fire stain, as well as by how well and uniformly the metal was annealed prior to heat treatment. But none of this is "memory" of a blue phase. Blue color, when there, simply indicates a thickness of an oxide layer. To a degree, this tells you something about the metal temp, but not much. And there's nothing about that temp that leaves a blue memory... Which is good. We don't wan't our silver to be all sad or something from bad blue memories... :-) By the way, blue itself is an interesting color to see on silver. Tarnish usually starts as faint to distinct yellowing, going to browns and then quickly to black. While there can be a peacockpuple//blue color in that range, it's ephemeral, and hard to actually get or keep when intentionally putting on a patina... However, the end black color, if you burnish it or rub it, so it's metallic and shiney, gets a kind of bluish gunmetal grey tone. Very pretty when intentional. But not really blue. More a bluish black. My guess as to why it's only just now showing up is that either something in your water or food has increased in sulphur content (Eating more, or different types, of eggs?), or equally perhaps, that your original fork had a surface that was somewhat copper depleted, and now you've worn your way through that layer, so a difference in tarnishing. Maybe both causes are in play. I am thinking that somehow annealing it again may be the cure but need some moral support before venturing back into this. If this is a surface oxide layer, heating it again and pickling, perhaps several times, will again deplete the surface of copper, leaving a fine silver thin surface layer. You have to then not buff it off, as it's thin. Use a fine brass scratch brush with soapy water to brighten it up again. But this is a temporary cure, since it will eventually also wear away. And, it anneals the silver. If before, when you made it, you did not anneal the metal after the last stage of forging or hammering, then the metal is harder. Annealed, the fork might be easier to bend... You might also consider simply silver plating it. Eletroplated silver is pure silver, not sterling, and if well done, the surface can be somewhat more resistant to tarnish than straight sterling silver. Or, buy a bottle of tarnex. Pretty aggressive at removing sulphide tarnish from silver and copper. Thiourea based, stinky stuff. But it works. Then a light buff to restore the shine if it suffered, since tarnex reduces the sulphide but doesn't polish. It's a dip. Quick to use. Or use the free method. Glass or plastic container, or an UNANODIZED aluminum container. A mix of washing soda (sodium carbonate) and warm water. If the container is glass or plastic, put a piece of aluminum foil in the bottom. Not needed for the aluminum container. Soak the silver in this for a while. The Tarnish will come off. The aluminum sets up an electrolytic cell with the silver. If no washing soda around, mix baking soda with a bit of salt, and use that. Quantities not critical Like Tarnex, this removes the discoloration, but does not repolish the metal. Oh, and the areas between the tines? I'd guess they get less burnishing/polishing when you clean the fork. So the surface may be a bit more porous. Use something like the fine brass brush I mentioned, or even very very fine steel wool, also with soapy water as a lube, to burnish the metal after it's clean of the discoloration. This compacts the surface, making it more resistant to re-tarnishing. Hope that's of use. Peter Rowe |
Silver Blueing
I was wondering when Peter would pop in and sort it all out.
Thanks for that explanation of the probable cause of the problem. I don't claim to understand it all but at least it fits the situation. At the very least, it reminded me of the pickling solution that I have been looking at for several years. I don't even remember what it is other than something I bought from a swimming pool supplier. I put about 2" in a beaker and heated it in the MO and put one fork in it for a most of a day. I kept looking at it and nothing ever changed. I gave it up and rinsed it off under water but when I wiped it with a towel, it was shiny and bright and still is after a few days. It probably won't last but when given ways to solve a problem, I always start with the simplest. ............ I have been getting group postings in my email using the email option. This is good but disappointing that one can not respond in email and have to come to the web to respond. Better than nothing I guess. Thanks for your help. I have a follow up question but will save that for another posting. Jack |
Silver Blueing
On Sat, 20 Feb 2010 12:55:04 -0800, in rec.crafts.jewelry Jack Schmidling
wrote: I was wondering when Peter would pop in and sort it all out. You give me too much credit. I don't have all the answers. Just decent guesses some of the time. :-) Thanks for that explanation of the probable cause of the problem. I don't claim to understand it all but at least it fits the situation. And as I say, it's just a guess. At the very least, it reminded me of the pickling solution that I have been looking at for several years. I don't even remember what it is other than something I bought from a swimming pool supplier. Most likely, a product like spa-down or ph-down, which are products intended to reduce the ph of hot tubs and swimming pools. the active chemical is sodium bisulphate, which is the same thing in commercially sold jewelers pickling compounds. It's a sulphuric acid salt, so it acts much the same as traditional sulphuric acid pickle, but safer, without the nasty fumes. Most other pool chemicals are chlorine compounds, which might also form an acid bath of used concentrated, but that would be a hydrochloric acid variant, which isn't effective as a pickle for silver because silver chloride isn't soluable, so such chemicals just form a nasty scummy surface on the silver. I put about 2" in a beaker and heated it in the MO and put one fork in it for a most of a day. I kept looking at it and nothing ever changed. I gave it up and rinsed it off under water but when I wiped it with a towel, it was shiny and bright and still is after a few days. The normally desired action of pickle compounds is to dissolve oxides, most commonly copper oxides formed when soldering or annealing. Tarnish, however, is sulphides, and these are not substantially affected by pickling. Pickle doesn't normally take off tarnish. But apparently, your extended soak did enough damage to the surface that it weakened the sulphide layer enough so it could be wiped off. At the same time, the extended bath also likely removed some surface-accessable copper, leaving a surface close to fine silver. That would tend to be slower to tarnish again, at least for a time. It probably won't last but when given ways to solve a problem, I always start with the simplest. Not a bad plan many times. ........... I have been getting group postings in my email using the email option. This is good but disappointing that one can not respond in email and have to come to the web to respond. Better than nothing I guess. For rec.crafts.jewelry, you DO have an email response option. Because the group is moderated, all posts sent to the group get forwarded by news servers to me for approval. I then repost acceptable posts to my own news server. That means that if you wish to send a message to rec.crafts.jewelry, one way to do it if you do not have direct access to a news server to post to, is to simply email the post to . So long as the post seems to be intended for the group, and not a personal message to the group moderator (me), then I simply treat it as I treat any other post to the group. Slightly more work for me, since posts sent this way do not already have a newsgroups header imbedded in them, so I have to add one. But that's minor. Note too, that you have many options for news access, even if your ISP doesn't offer a news server. There are commercial news servers that sell premium access (usually increased speed, or a larger number of accessable newsgroups, or the like) over standard ISPs. Some of these offer a basic free level of access. Once you've established an account and configured your news reader, any internet connection will do. Peter Rowe moderator rec.crafts.jewelry |
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Avoid using rubber gloves when washing the silver, as rubber corrodes silver. (The pictures opposite to see you here, will be) where rubber gloves were worn, use a soft cloth gently rub the silver clean and dry immediately with a soft towel. Dull silver with a soft cotton cloth gently glowing skin. |
Glad to see a few names here that I recognize from the past. I tend
to hop around from hobby to hobby like a jack in the box and have been obsessed with amateur radio for the past several years. I have been a ham since 1955 but out more than in. |
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