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#1
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Flatware
Having exhausted Peter, myself and rec.crafts.metalworking, trying to solve
the problem of casting a simple cup, I am ready to move on to something seemingly straightforward. A picture of my problem cup is at http://schmidling.netfirms.com/cup.jpg As always, I am open to suggestions as we obviously missed something. That and one like it was cast in fine silver and things only got worse using sterling, zinc/silver. Zinc and aluminum produced perfect castings. Most of the effort has been aimed at higher temps but even at 1950F with sterling it was the same story. This is a sand casting project and poured in the position shown in the picture. The spure is the stem. Anyway, my next project is a simple butter knife. I don't anticipate any problems with the handle but I am curious to know if it's possible to make the knife part out of sterling. I could cast the whole piece in one pour that way. ha ha.. famous last words. As a point of interest, the knife I am using to plagarize my pattern is an interesting piece. Other than the pattern that I like, what caught my attention was a little sliver of metal poking up. I pulled on this and pulled up as thin strip almost an inch long. Under this is some chalky looking stuff that is obviously a core. This did't surprise me much but what did was the fact that it has "sterling" stamped on the side. I gather sterling says nothing about being solid silver or hollow? There is also a very conspicuous parting line on the handle which does not make much sense if this is not a casting. The blade itself says Ambassador Cutlery Sheffield Eng. Is this an imposter? I thought Sheffield was a brand name. js -- PHOTO OF THE WEEK: http://schmidling.netfirms.com/pow.htm Astronomy, Beer, Cheese, Gems, Sausage, http://schmidling.netfirms.com |
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#2
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Jack Schmidling wrote:
The blade itself says Ambassador Cutlery Sheffield Eng. Is this an imposter? I thought Sheffield was a brand name. My good man, Sheffield is a city in England. Abrasha http://www.abrasha.com ((this post edited by the moderator. C'mon, Abrasha, we've been down this before. don't make me do this. PWR.)) |
#3
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On Thu, 23 Sep 2004 18:21:36 -0700, in hõ Jack Schmidling wrote:
Having exhausted Peter, myself and rec.crafts.metalworking, trying to solve the problem of casting a simple cup, I am ready to move on to something seemingly straightforward. A picture of my problem cup is at http://schmidling.netfirms.com/cup.jpg As always, I am open to suggestions as we obviously missed something. Everyone, Jack and I have been over this a number of times via email, trying to figure what he can change to get this mold to cast. I'm not sure it can be, but it looks doable, and certainly, sand casting can do thin sections. I've covered about everything with him I can think of, and he's tried a wide number of changes, short of just switching to an investment mold which could be heated. So any of you with foundry experience sand casting silver, or other means of casting into an only warm mold, would be welcome to suggest ideas. I'm kinda stumped, but don't have extensive enough sand casting experience to be sure I'm not missing the obvious here. Peter |
#4
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On Thu, 23 Sep 2004 18:21:36 -0700, in ?? Jack Schmidling wrote:
Anyway, my next project is a simple butter knife. I don't anticipate any problems with the handle but I am curious to know if it's possible to make the knife part out of sterling. I could cast the whole piece in one pour that way. ha ha.. famous last words. You can make the blade out of sterling. I'd suggest, though, that a simple cast blade will be rather soft and easily bent. The handle, if thicker, would resist that. But make your pattern with a somewhat shorter, narrower, and considerably thicker section where the blade will be, and then forge that portion of the casting, or roll it (if your rolling mill will do it) to thin it out. That will make the blade denser, stronger, stiffer, and much more servicable as a blade. And it will polish up better too. Plus, it will be easier to cast. As a point of interest, the knife I am using to plagarize my pattern is an interesting piece. Other than the pattern that I like, what caught my attention was a little sliver of metal poking up. I pulled on this and pulled up as thin strip almost an inch long. Under this is some chalky looking stuff that is obviously a core. This did't surprise me much but what did was the fact that it has "sterling" stamped on the side. I gather sterling says nothing about being solid silver or hollow? There is also a very conspicuous parting line on the handle which does not make much sense if this is not a casting. This is very common. The sterling stamp indicates that the metal content is sterling. It does not imply anything about the total weight of the piece, or about non-metal additions. Less expensive sterling or silver plated items are often made of stamped thin sheet metal, then filled with pitch, rosin, or as seems likely from your description, plaster or the like, to give the piece rigidity and weight. works fine, and greatly reduces the silver content, and thus the cost of the piece. Very common. When you find commercially made silver or silver plated candle sticks, for example, you can almost always count on them using construction similar to this, at least in the base, which is often weighted down this way. The parting line is not a parting line from casting. The halves are stamped. The "parting line" you see is a flange left intentionally from stamping that forms a slightly wider surface than just the edge of the sheet metal would do, allowing some good surface area for the two stamped halves of the piece to be soldered together. The blade itself says Ambassador Cutlery Sheffield Eng. Is this an imposter? I thought Sheffield was a brand name. js Sheffield in this case, means that the Ambassador cutlery company is located in Sheffield England. It's the city where, around 250 years ago, silversmiths originated the process whereby copper was clad, using heat and pressure, with a thin sheet of sterling silver. Similar to the product called "gold filled" when it's a gold layer. That clad laminate sheet is then used to make "silverware" that's much less costly than solid sterling silver. It differs from the somewhat more common (today) electroplated ware in that the silver layer is generally thicker, as well as the fact that the clad layer is sterling silver, while electroplate is generally a fine or nearly fine silver layer over the base metal. Solid, again, simply means that the metal itself is sterling silver all the way through. It does not mean a knife handle cannot be hollow, or filled with a reinforcing agent like plaster. The term "Sheffield plate" is used to refer to items made using this type of metal and process. It may also be a trademark for some company, but I'm not specifically aware of that, and wonder whether the common usage of the term might make it actually difficult to get such a trademark approved, but I'm not sure of that... Do a Google on Sheffield plate for more info... Peter |
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"Peter W.. Rowe," But make your pattern with a somewhat shorter, narrower, and considerably thicker section where the blade will be, and then forge that portion of the casting, or roll it (if your rolling mill will do it) to thin it out..... Forget the mill but that is exactly what I just got finished doing. I made one mold of just the handle and another one with handle and blade and gouged a trench on both sides to provide meat for forging. Kind of fun adding a new found skill to a new challenge. If this does not work out, my fallback is the handle which I can probably attach the blade from the cheezy knife. How is the blade likely attached to this handle? I was pondering just cutting it off in the band saw but I am not sure where to cut nor how hard the tang might be. Less expensive sterling or silver plated items are often made of stamped thin sheet metal, then filled with pitch, rosin..... Ah... that was my next question. I wired down the loose piece I mentioned, fluxed it and was going to solder it but rosin like goo started oozing out all over and started to burn. My wife was not real impressed with my repair job. .............. Question.... what is binding wire? I know what it's for but what is the material. This is not mentioned in any of my catalogs. I used nichrome for this job and it's a good thing it didn't work as I later found that is solders very nicely with silver. js -- PHOTO OF THE WEEK: http://schmidling.netfirms.com/pow.htm Astronomy, Beer, Cheese, Gems, Sausage, http://schmidling.netfirms.com |
#6
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On Thu, 23 Sep 2004 22:31:08 -0700, in |õ Jack Schmidling wrote:
If this does not work out, my fallback is the handle which I can probably attach the blade from the cheezy knife. How is the blade likely attached to this handle? I was pondering just cutting it off in the band saw but I am not sure where to cut nor how hard the tang might be. Usually, the blade is normally stainless steel, unless it's silver like the rest of the handle metal. Normally there is a tang that extends up inside the handle, supported by the rigid filling, and the silver handle is then usually also soldered to the bolster portion of the blade You'd remove the blade by filing or sanding away the silver solder joint, and then pulling away the handle and it's filling after heating it enough to soften that filling cement. (It's a cement, often something like rosin "filled" with plaster, or some similar meltable resin or glue.) You likely will seriously damage or destroy the handle in the process, at least with the first one. keep the tang intact if you can, to better secure the blade to your new handle. If you're making this with a steel blade, and casting the handle solid, you might be able to shape the tang in such a way that it has drilled through holes, or notches, or some other device to hold it in the handle, and make your sand mold so the blade is also in the mold, with the tang extending into the mold cavity. Then the silver is cast right around the tang. Since the casting shrinks on cooling, if this works right, you'll get a tight strong fit. You might then finish the junction between blade and handle with added solder if it needs it .. Less expensive sterling or silver plated items are often made of stamped thin sheet metal, then filled with pitch, rosin..... Ah... that was my next question. I wired down the loose piece I mentioned, fluxed it and was going to solder it but rosin like goo started oozing out all over and started to burn. My wife was not real impressed with my repair job. this sort of damage can be exceedingly tricky to repair really well. You might try just gluing the errant bit back down to the core with epoxy as a partial, somewhat cosmetic fix. the problem is not just the melting filling. it's also that generally, the sheet silver shell is made of very very thin silver. Breaks of this sort are tricky to solder even after you've disassembled the knife, removing the filling (and probably the blade), because the silver is so very thin, likely not clean on the inside, and the edges likely don't meet all that well. It can be done with a laser welder, but doing a good job with a torch requires more skill than many people have, as well as patience and a good deal of fuss and bother disassembling thing and putting it back together later. Usually, it's not worth the trouble unless the piece is especially valued. ............. Question.... what is binding wire? I know what it's for but what is the material. This is not mentioned in any of my catalogs. I used nichrome for this job and it's a good thing it didn't work as I later found that is solders very nicely with silver. Several types of wire are sold as binding wire. the most common is plain annealed black iron (mild steel, with a black oxide surface) it does not resist being soldered if flux or a reducing flame hits it. One avoids soldeirng the wire by holding the object with the wire shaped so it avoids actually touching the solder joint. One can build little scrap metal bridges to allow the wire to pass over the joint, or more commonly, one bends loops in the wire so the loops are positioned just over the joints, letting the wire be up over the solder joint at just that section, while still providing the needed hold. those loops also are easy to pull and stretch and tighten, given you a means to more easily adjust the tension the wire exerts on the pieces.. In addition to ordinary black iron wire, stainless steel, of the mild non hardenable type, is also often useful, because it does not cause the nasty reactions in your pickle, so you don't automatically have to bother removing it before the piece goes in the pickle. I've also now and then used titanium wire. The oxide surface of titanium generally tends to resist solder, unless one of the more active soldering fluxes is used. It also has an advantage over iron wire in that it doesn't melt as easy. but it costs more. Hope that helps. Peter |
#7
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"Jack Schmidling" wrote in message ... Having exhausted Peter, myself and rec.crafts.metalworking, trying to solve the problem of casting a simple cup, I am ready to move on to something seemingly straightforward. A picture of my problem cup is at http://schmidling.netfirms.com/cup.jpg It looks like you haven't used enough metal to pour. I would want a bit more that what you have there... Also, where's your gas escapes? -SP- js |
#8
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"Jack Schmidling" wrote in message ... Ah... that was my next question. I wired down the loose piece I mentioned, fluxed it and was going to solder it but rosin like goo started oozing out all over and started to burn. My wife was not real impressed with my repair job. Heh... Well, you won't be able to repair it unless you remove the rosin, clean it thoroughly, then solder the seam. You might find that it was rivetted in the first place, so filling the handle again, and re-rivetting is not impossible. Question.... what is binding wire? I know what it's for but what is the material. Iron. -SP- js |
#9
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"Peter W.. Rowe," wrote:
I'm kinda stumped, but don't have extensive enough sand casting experience to be sure I'm not missing the obvious here. Peter, You may be a saint in dealing with this [[headstrong beginner]] (edit. PWR), and yes you ARE missing the obvious here! It's just not done this way. Chalices are just not cast unless you want a thick skinned one, which might be a fine metaphor for our thick skinned friend here. The only right way to do this, is the way this has been done for many centuries. And that is to get out the hammers and stakes. You can hammer the main body of this puppy in a day. An experienced silversmith will do it in a few hours. Ask Ted, he'll tell you. Abrasha http://www.abrasha.com |
#10
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Jack Schmidling wrote:
Having exhausted Peter, myself and rec.crafts.metalworking, trying to solve the problem of casting a simple cup, I am ready to move on to something seemingly straightforward. A picture of my problem cup is at http://schmidling.netfirms.com/cup.jpg As always, I am open to suggestions as we obviously missed something. Temperature, You missed. Casting is "frozen" during normal fillig process of form. Three possibilities to help. 1. Higher melting temperature 2. Changing alloy to one wich is more fluent (800 silver or sterling silver with an add of 2 % zink oder better with AC 9.103 or both) and has a lower melting point, so the difference between melting point of the alloy and the real used melting temperature is bigger. (Minimum for that casting shown, I think should be 200 degrees Centigrade. 3. Adding some more casting sprues at the sensible points (now holes) That and one like it was cast in fine silver and things only got worse using sterling, zinc/silver. This is only possible, if that castings were made with lower casting temperature. Fine Silver has higher melting/freezing point than sterling silver. However if sterling silver seems molten in the beginning, it contains inside some firm crystals. So it takes some time longer melting and higher temperature to melt it completely. Look for liqudus and solidus temperatures for deeper information. Good luck Grüße, Heinrich Butschal -- www.juwelen.online-boerse.org www.meister-atelier.de www.schmuckfabrik.de www.medico.butschal.de |
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