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#11
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On Sat, 17 Jul 2004 00:19:11 -0700, in ¸ô Jack Schmidling wrote:
Adding 7.5% copper to molten silver does not sound like much of a challenge either. Rather than melting the silver and adding solid copper to it, just put both together, cold in the crucible, with the copper on the bottom (to limit oxidation), and melt both at the same time. You won't then need it to get quite as hot, as sterling melts at a lower temp than either fine silver or copper. Peter |
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#12
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On Sat, 17 Jul 2004 00:19:15 -0700, in Ìô Jack Schmidling wrote:
You know, if you unfriendly types would read my message instead of reacting to my name, things would be much more pleasant. In this instance, Jack, I think Ted was attempting a bit of satirical humor, not insult. He's impressed by the scope/scale of your projects. Most newcomers are happy if they can manage, with much help, to cast a small thing like a ring. Though I understand you've had prior sand casting experience, perhaps Ted missed that. For a beginner, just jumping into casting something the size of a chalice is rather more than a normal beginning task. Again, I'm reminded of the old adage/definition, which states that experts are the guys who know all the very many reasons why a thing is impossible, or should not be done. Meanwhile, an amateur is the guy who, not knowing a thing is impossible, goes ahead an naively does it... Sand casting will give a most unusal texture to the surface.... That's why someone invented the lathe. Sand is more than adequate for anyone other than a Troglodyte whose most sophisticated tool is a hammer. now now. Be nice. Actually, hammer work is capable of far greater delicacy than you can get with casting, even high tech methods other than simple sand molds. For one thing, wrought silver, has a much finer crystal structure without the pores and defects common to castings. The result is denser metal that's much stronger, harder, and will take a much higher level of polish. All the best holloware is made either by such methods, or on the commercial level, via spinning lathes which also start with rolled/milled sheet metal and form it to the desired shape by deforming, compressing, and otherwise working the metal the way hammers do. It's also a good way to build up strong wrists and arm muscles, as well as a good way to drive everyone in the neighborhood quite mad due to the noise... And with hand raising (as the process of developing such forms with hammers and stakes is called), you're not limited to the shapes one can turn on a lathe. ovals, varied faceted forms, and completely free form assymetrical forms are all possible. Who said anything about using 100 oz for the cup? I said I have a number of such ingots. Is it not possible just to use some of it? Certainly nice to use. the other option would be to cast a cylinder from the silver, then turn the whole chalice up in a lathe. Fine silver turns very well. that way you would achieve the shape and size without any soldering atall. good lateral thinking...... Duh! But why not cast it close to the final shape and save a lot of hogging? Again, Ted strayed into the realm of humor... Youll find using pure silver a much better option to the traditional sterling ..... Ah.... finally something useful. Fine silver doesnt get fire scale like the 925 alloy. To answer your last question it isnt neccessary at all to alloy silver nor alloy gold. Pure silver has the most beautiful white colour. When you see sterling along side it theres no comparison...... So what is the point of sterling? Surely not to save a little silver. Actually, this can be open to opinion. While fine silver has a white color, and is not prone to the oxidation problems of sterling silver, it is considerably softer. This softness, which makes many thinner forms impractical to make or use, is the big disadvantage of fine silver. for example, you might make a chalice via casting that might have a fairly delicate looking stem. With sterling silver, that stem could be thinner, and still have enough strength, while in fine silver, it would not be hard to make a stem that looks nice but would be prone to bending when used. In the case of Ted's die struck items, the work hardening of the striking process makes the silver quite hard enough to hold up. but a fine silver casting will be fully annealed. That will be a very soft piece of metal, compared to the same thing in sterling silver. Making broach settings are easier done by hammering the silver into a die. the bigger the hammer the better..... Where does one get the dies? I can't even find decent broaches. Ted actually does something here most craftspeople don't do. he uses die striking, via high pressure presses, or the old style of drop hammer (when he refers to a 275 pound hammer, it's not one with a handle that you lift with one arm, or even a normal sledge. it's likely a 275 lbs steel striking form that drops in a frame to hit a die set mounted in the base. Making the dies is the tool and die makers art. Generally one does not buy them, unless one gets lucky and finds what is needed in some old defunct manufacturers stock, or on ebay where such antique dies may be sold, etc. Gold machinery in providence R.I. has bins and bins of the old dies. Commercially, these days, much more work is produced by lost wax casting. (in investment, not sand. investment looks a lot like plaster, but takes high temps, and produces much smoother castings that you get with sand.) Ill give some thought to making a chalice this way, could be a new development. You might need a real man's hammer for that one. his 275 lb drop hammer would do it. Take a weight of that size, and drop is from a height of, say, five or six feet. Calculate the energy imparted at impact. It's quite a lot... Note that larger foms might be developed using a sequence of progressive dies, not just one single strike. |
#13
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On Sat, 17 Jul 2004 00:19:19 -0700, in =F4=07=F4 Jack Schmidling arf@mc.=
net wrote: I thought copper melted at a significantly higher temp than silver? Wouldn't this increase the melt point of silver if added? =20 Both fine silver and pure copper melt at a higher temp than does the mixt= ure of the two. When the two solid metals are heated, they will start to dissol= ve into each other and melt where they contact each other, at a temp lower t= hat either one's melting point. think back to lamedeer's mention of the way tin/lead solder dissolves copper in soft soldering, which occurs way bel= ow the melting point of copper. =20 I guess ignorance is bliss as I never had any problems with it in the p= ast but never made anything quite this big either. maybe you wont' have trouble. I'm simply mentioning one difference betwe= en fine silver and sterling silver that could be a source of trouble. That = does not mean it WILL be a problem. It would be most likely to be an issue if= your chalice shape has some areas that are thin, adjacent to other areas that = are significantly thicker. The thicker areas might tend to contain increased= pores or cavities, etc,. proper sprues can prevent that. The only thing I have a problem melting is pure copper but there is not much call for that anyway. And a good thing, too. pure copper is indeed quite difficult to cast. N= ot just for you. =20 Sounds like a good approach. I had the noting that it was too soft for= this sort of thing but I am certainly not looking for extra hassle. Alloying it down is no extra hassel. just include the appropriate amount= of copper at the bottom of the crucible when you melt the silver. The hasse= ls you'll get would be in then cleaning up the casting, which in sterling mi= ght have increased oxidation. As I mentioned, if you're planning to turn the= thing on a lathe anyway, that will be inconsequention. The greater hardness = of sterling might make it easier to mount the shape on the lathe without distortion... peter |
#14
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"Jack Schmidling" wrote in message ... So what is the point of sterling? Surely not to save a little silver. Pure silver is very soft. Jewellery would wear away in a couple of years, forks would bend, as would your gobblet stem if it were proportioned correctly. -- William Black ------------------ Strange women lying in ponds distributing swords is no basis for a system of government |
#15
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"P.W. Rowe, moderator, r.c.j." wrote in message ... Making the dies is the tool and die makers art. Generally one does not buy them, unless one gets lucky and finds what is needed in some old defunct manufacturers stock, or on ebay where such antique dies may be sold, etc. There's a guy on the re-enactment scene in the UK who is making coin dies for historic coins, all marked so that collectors know that the resultant coins are modern copies. He's charges reasonably low prices for his dies, less than £120 (about $200) last I heard. -- William Black ------------------ Strange women lying in ponds distributing swords is no basis for a system of government |
#16
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P.W. Rowe, moderator, r.c.j. wrote:
a good way to drive everyone in the neighborhood quite mad due to the noise... There were about 20 people in my silversmithing course. If we didn't all lose significant hearing I'd be surprised. The kind of shock your holding-hand experiences is similar to the kind that gives "white hand" to jackhammer operators, but I've never heard of a silversmith getting it, so it must be significantly less severe. -- m http://www.mbstevens.com/ |
#17
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Roger on all. Now for a more simple starter, I am back to the broach, pure
silver sounds like the ticket. I went to the local library yesterday and could not find a single useful book on jewelry so, for good or evil, this is going to have to be my source of info. Where I am stuck is setting stones into the cast broach. I also gave up in disgust, trying to hard solder a hanger on the piece I am practicing on. I cast a 1" diameter bar that I cleaned up in the lathe and have something like a fat nickle. I drilled a hole in one edge and put the ends loop of silver wire and attempted to solder this in using Xeasy solder and Handy Flux. Nothing would make the solder ball wet the piece. So I just TIXed it and got past that evil with another evil. But back to setting stones, I came up with an approach that works but is tedious and not quite as pretty as I would like. I would like to know if this makes sense and/or a better way. I put the nickle in the lathe and drilled a small hole in the center and with a countersink, made a nest for a 12 mm SRB so that is sat just just above the girdle. I poked a tool bit into the face just at the 12mm point and made a circle to use for drilling 4 holes around the stone. Into these holes I soldered short pieces of the Xeasy (it's the only silver wire I have on hand) using TIX. After trimming and cleaning up the ends, these became the prongs to hold the stone. It works but I can't seem to keep the solder inconspicuous and cleaning up after the prongs are on is a big problem. Any thoughts.. better ideas? js -- PHOTO OF THE WEEK: http://schmidling.netfirms.com/weekly.htm Astronomy, Beer, Cheese, Gems, Sausage, http://schmidling.netfirms.com |
#18
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On Sat, 17 Jul 2004 10:13:25 -0700, in ¸ô Jack Schmidling wrote:
Roger on all. Now for a more simple starter, I am back to the broach, pure silver sounds like the ticket. I went to the local library yesterday and could not find a single useful book on jewelry so, for good or evil, this is going to have to be my source of info. Or, you could spend a few bucks and actually buy a book. A lot of folks have gotton good starts with Tim McCreights "complete metalsmith" books, and there are many others out there worthy of notice. Too bad your library is so poorly stocked. If you can find a Borders or Barnes and Noble book store around somewhere, they usually have a decent, if variable, selection. Or try ebay. Charles Lewton-Brain sells a number of find books through ebay, at a good price, including his recent (and wonderful) translation of the classic german text on goldsmithing, Brehphols "Theory and Practice of Goldsmithing". Where I am stuck is setting stones into the cast broach. I also gave up in disgust, trying to hard solder a hanger on the piece I am practicing on. I cast a 1" diameter bar that I cleaned up in the lathe and have something like a fat nickle. I drilled a hole in one edge and put the ends loop of silver wire and attempted to solder this in using Xeasy solder and Handy Flux. Nothing would make the solder ball wet the piece. So I just TIXed it and got past that evil with another evil. You simply didn't get it hot enough. Hard soldering a small piece onto a larger thick piece in silver can be problematic, since silver is such a good heat conductor. In your case, you pretty much didn't need to be heating the jump ring hardly at all, but needed to be getting the pendant part quite hot. Here's an experiment. In a dark, or mostly dark room, see how much heat is required to get that pendant part, very slightly glowing. I say a dark room, because with the lights on, you won't yet see the glow till it's a bit hotter than you need. But that's about the temp (around 900-1000) that you need to reach for the easy/extra easy solders.. If both parts of to be joined are at that temp, and you've got a bit of the solder in contact with the metal at the joint (not just floating on an excess of flux. Sometimes you have to push it back through the flux to contact the metal), have some flux on the joint protecting it, then you WILL get it to flow. If it does not flow, then either: 1. You didn't get it hot enough, or you only got one part hot. This can be a problem with those little butane torches, like the blazer, or the cheaper copies. If you're using almost any torch burning propane, like a hardware store type plumbers torch, or the like, you'll be OK. the little micro flame torches such as the little torch, even with oxy-acetyelene, sometimes are too small a flame for working with silver, at least until you get to the largest tip sizes. 2. You had so much flux on the joint that the solder floated. It won't flow onto the joint unless it's in contact with it. Not enough flux would be evidenced by a resulting layer of black scale/oxide on the joint area after it cools. 3. Your metal wasn't clean in the first place. The flux dissolves oxides, but it won't help if there's grease or dirt on the joint. The metal should be clean and bright. Try it again. But back to setting stones, I came up with an approach that works but is tedious and not quite as pretty as I would like. I would like to know if this makes sense and/or a better way. I put the nickle in the lathe and drilled a small hole in the center and with a countersink, made a nest for a 12 mm SRB so that is sat just just above the girdle. I poked a tool bit into the face just at the 12mm point and made a circle to use for drilling 4 holes around the stone. Into these holes I soldered short pieces of the Xeasy (it's the only silver wire I have on hand) using TIX. After trimming and cleaning up the ends, these became the prongs to hold the stone. It works but I can't seem to keep the solder inconspicuous and cleaning up after the prongs are on is a big problem. Any thoughts.. better ideas? If you did this with a good silver solder, soldering silver wire, rather than solder wire, the appearance would be much better, as the solder would visually blend in. also, such a solder joint is strong enough that you don't need to drill holes. it can be a butt joint. That's not the case with Tix. Because you drilled and inserted the wires, you have a mechanical connection as well as a solder one. The result is that your use of TIX will work in this case, as with that joint construction, you have sufficient strength. But as you've discovered, and as we've been trying to tell you all along, there are aesthetic issues connected with Tix and other soft solders. They just don't look as good. Also, when it comes to setting the stone, you'll find the solder wire to be a lot stiffer and harder to bend properly, than is sterling or fine silver. It can work, but with increased difficulty and risk to the stone. Also, it's color is not as nice as sterling. the other difficulty in using Tix or soft solders is that once you've used it on the piece (such as on the bail), then it's all you can use on other parts of the piece, since you no longer have the option to heat it to silver soldering temps. As to cleanup, however, there ARE tools that will do that job. cleaning up around that type of solder joint is generally first a matter of filing or scraping off the obvious lumps and masses of extra solder. fine cut needle files work well. Be SURE to clean off any traces of soft solder from the fines, or if you then use them on silver you plan to silver solder, it's possible to transfer bits of the Tix to clean sterling without realizing it, which then causes trouble when you silver solder that next piece. Or reserve a set of files only for use around soft solder. After the lumps are gone, then various light abrasives and buffing/polishing tools can be used to blend and smooth. Probably the most effective, rather than cloth type buffs, are small bristle brushes, which get around prongs and the like. used with tripoli or white diamond buffing compound, these will smooth nicely. Then use a clean brush with rouge to polish. Another tool that's recently been introduced are the 3M radial bristle disk brushes. Thes are a brush with imbedded graded abrasives, and using successive grits of brush would do a very nice job with your taks, even with soft solder. But the things are pricier than traditional bristle brushes with compound. note that the radial bristle disks are sold in multiple packages for a reason. While you CAN mount just a single disk on a mandrel and use it that way, they work a LOT better when stacked up four to six at a time. buy accordingly. Rio carries them, as do most of the other bigger tools suppliers these days. Wonderful product. Still, i'd recommend that at first, you just try the old method of the standard bristle brush (such as those sold under the dremel brand) with some tripoli compound, and see if you can get that to work. You may have trouble getting all of the exces Tix cleaned off, so there may still be some areas right at the bases of the prongs where you'll have to live with a bit of that color difference. Perhaps you can electroplate over it... Peter Rowe |
#19
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Peters treaties on fettling up and polishing will tell you what the
jewellery polisher would have at his disposal and use for such a piece. If you dont have such a well equiped polishing section in your w/shop , theres another way. Most rewarding but more time consuming. Its a little known technique used in the darkest stygian workshops in the Old Birminham jewellery quarter wherby you use a piece of string to polish around work and inside holes.. String dia is usually half the hole size or the dia of the radius you want on thebottom of your stone setting wires. and you take a length as long as you can handle synnthetic preferably cotton , rub it up and down on your polishing compound block, feed it through the hole or around the part you want to polish and pull to and fro o. Give it a try,youll bepleasantly surprised how well it works. you also dont polish your fingernails or lose the work down the lemmel vacumn pipe and through the suction fan like you can with rotary machine polishing. Unless youve been trained in the use of these machines you can get seriously inhjured. I wont frighten you with the gruesome tales of injuries to polishers.. BUT......... NEVER EVER leave a tapered screw polishing spindle running or even stationary unless it ALLWAYS has a felt bob , or mop thereon. IF you dont and you get it in your clothing itll screw through cloth and into your flesh before you have time to throw the belt off the drive to the loose pulley. Jack Schmidling wrote: Roger on all. Now for a more simple starter, I am back to the broach, pure silver sounds like the ticket. I went to the local library yesterday and could not find a single useful book on jewelry so, for good or evil, this is going to have to be my source of info. Where I am stuck is setting stones into the cast broach. I also gave up in disgust, trying to hard solder a hanger on the piece I am practicing on. I cast a 1" diameter bar that I cleaned up in the lathe and have something like a fat nickle. I drilled a hole in one edge and put the ends loop of silver wire and attempted to solder this in using Xeasy solder and Handy Flux. Nothing would make the solder ball wet the piece. So I just TIXed it and got past that evil with another evil. But back to setting stones, I came up with an approach that works but is tedious and not quite as pretty as I would like. I would like to know if this makes sense and/or a better way. I put the nickle in the lathe and drilled a small hole in the center and with a countersink, made a nest for a 12 mm SRB so that is sat just just above the girdle. I poked a tool bit into the face just at the 12mm point and made a circle to use for drilling 4 holes around the stone. Into these holes I soldered short pieces of the Xeasy (it's the only silver wire I have on hand) using TIX. After trimming and cleaning up the ends, these became the prongs to hold the stone. It works but I can't seem to keep the solder inconspicuous and cleaning up after the prongs are on is a big problem. Any thoughts.. better ideas? js |
#20
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On Sat, 17 Jul 2004 13:50:54 -0700, in |ô "ted.ffrater"
wrote: Most rewarding but more time consuming. Its a little known technique used in the darkest stygian workshops in the Old Birminham jewellery quarter wherby you use a piece of string to polish around work and inside holes.. Not all that "little known", Ted. Most experienced jewelers I know, use string like that. for those holes, crevices, and other hard to reach openings, it's not only sometimes the only way to reach and polish them, but often, people are surprised at how fast it can work. However, my understanding of Jack's situation is wires protruding from an otherwise flat surface, with solder to be cleaned up not just on the base of those wires, but likely, more problematically on the flat surface near those protruding wires. For that, string is less effective. The little rotary brushes I had in mind are not the bushes on a (usually) wood hub to be mounted on a tapered spindle on a fixed polishing machine. while these are often what we pros might use, I am assuming that Jack's setup does not yet include that degree of polishing equipment. The brushes I had in mind are those small mounted wheel brushes (also available as cup shapes and end brushes) mounted on a 3/32 or 1/8 inch shaft for use in dremel or other small portable rotary tools (or for us, your flex shaft machines) . The ones i use most often are 7/8 inch diameter wheel brushes in several grades of bristle (the white very soft ones are wonderful for very delicate work and with rouge) Also, a note regarding brushes for polishing, for those not so used to them. use the shortest length bristle you can, for a given use. Longer bristles don't work as quickly and effectively, especially for initial cut down work where you're actually needing to remove scratches, rather than just bring up a high polish. If you need longer bristles to get into an area, then fine, but shorter ones remain more aggressive when you can use them. peter |
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