removing silver plate with a torch

I read somewhere on the web that a guy uses a torch to just melt the silver plating off of plated items such as silverware. The theory behind this I guess is that the melting temperature for silver is less than that of other typical metals that it is normally plated to. So I guess is that the silver just melts off and drips onto a surface and then can be collected for futher processing. Has anyone ever ever tried or heard of this. And yes, I know that many feel it is not economically feasible to worry about silver plated items, but I am just a hobbyist and not really concerned about the cost because I'm just playing around. I just want to know if this is a feasible idea. Thanks.

Paul

iam pretty sure the melting point of the base metals are close or lower than the silver depending on what type ... dont think its going to work .. i have some silver plated spoons i will give it a try but i have my doubts

Color me skeptical. It has been discussed on this forum what the underlying metal(s) is/are under silver plating for things like flatware, and no consensus was reached. Nor do I myself think there is a "standard" metal underlying silverplate on forks, for example. Different manufacturers used different metals, and while much (certainly not all) of it is probably brass + + + other stuff, there are many, many different flavors of brass. Nobody knows what particular alloy is used, and it's not even a given that Towle used this alloy of brass from 1937 to 1948 and that alloy from 1948 to 1961. Now, google "melting point metals" and you'll find that silver melts at 961 C and brasses melt in the 900-940 range. So for your idea to work, you'd have to be able to control torch heat impossibly delicately...on a piece of metal that is thick in the handle and thin in the tines, with the underlying metal generally having a lower MP than the silver you are after. Never mind the cost, I can't see it working hardly at all. And then...you're bound to get some junk metal in with your silver....so you'd have to refine it chemically, with the attendant costs. How much silver can you expect to get from a plated fork? I have no idea, but I'd estimate it to be in the half-gram range. You can certainly try your idea with some flea-market plated items at low cost but I seriously doubt there's much possibility of success obtaining silver metal out of it at the end of the exercise.

I think, it could be possible. Pure metals melt faster than alloys and what is more, they do tend to stick together. So with alittle bit of practice and a decent difference of melting points it could work.
I have observed this when melting goldplated pins from motherboards. The gold tends to melt faster an drip down, collect at the bottom, whereby the coppercore remains in shape. It does not always work but sometimes it´s possible. But the resulting plating on the bottom is very, very thin because of the tiny amount of PMs.

Pure metals melt faster than alloys and what is more, they do tend to stick together.

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There is nothing about that sentence I agree with. Eutectic solder, for example, melts at 183 C, while tin melts at 232 C and lead at 327.5 C.
Most brasses melt in the 900-940 range. But "red" brass melts right around 1000 C. Copper melts at 1084 C and zinc at 419.5 C. Cupronickel melts between 1170 C and 1240 C. Nickel, at 1453 C. There are many alloys that form eutectic mixtures whose melting point is below that of the pure metals that comprise the alloy.

And we are not talking about an alloy, we are talking about a layer of plating. Under torch heat, the layer of plating is going to behave differently than a consistent alloy mixture. Who knows, maybe it would flake off the underlying metal? Maybe it would melt off. I don't know. I find it hard to believe one could successfully melt a higher MP metal off a substrate of lower MP metal, especially with a crude torch, with constantly changing thicknesses of metal (the fork, not the plating) involved.

As I said, it would be cheap enough to try.

I think it is not possible to sweat off the silver unless it is very, very thick, which is very unlikely on any plated material. Even then, it will most likely leave a coating of silver of the copper base.

I once had several drums of aircraft bearings which had an extremely thick coating of silver on a mild steel base. The silver was many, many times thicker than the silver plate on even the highest quality dinnerware. The first thing I tried was to sweat the silver off with a torch. Some of the silver beaded up and dripped off. All in all, though, I couldn't remove more than half of the silver in this manner. The interplay between gravity and surface tension play a large part in this, I feel. If the beads formed are large enough, they will overcome the surface tension and fall off. When the beads are small, you can run them around on the surface with the torch but they won't drip off. I tried banging the parts to dislodge the beads. This worked somewhat but I was always left with a heavy layer of silver coating the steel and a lot of small stuck beads.

With silver on copper. I would think it would be worse, due to the production of copper oxide.

Marcel,

You said that pure metals melt faster than their alloys. By that, I assume you're saying the melting point of the pure metal is lower than that of an alloy of that metal. That is generally an untrue statement and, in most cases, it is just the opposite. For example, the melting point of silver is 1761F and that of copper is 1981F. Sterling silver, an alloy of 92.5% silver and 7.5% copper, has a melting point of 1640F.

Element,

Sorry to, in essence, repeat what you said, but I had already written my response before seeing your post. You did bring up a good point. The substrate on most all dinnerware is a copper alloy and, if yellow, the melting point could very well be below that of silver. If white, though, it is likely to be nickel silver, with a MP or 2030F. Also, as you said, some of the silver might flake off. Possible, but I doubt it. Unless there is heavy nickel under the silver, I would guess that, at that temperature, the silver would migrate into the copper before that happened.


All in all, sweating off the silver is a terrible idea. One would be lucky if any of it came off.

silver is a great solder (or brazing) for copper, heating silver would just solder the silver to the copper. melting too hot would just make an alloy of the metals, one metal in the melt would change the melting point of the other metal to form an alloy (of these two metals) which will now have a different melting point (alloy melting point),than that of the two metals that were originally in the melt.

element47.5 said:

Pure metals melt faster than alloys and what is more, they do tend to stick together.

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There is nothing about that sentence I agree with. Eutectic solder, for example, melts at 183 C, while tin melts at 232 C and lead at 327.5 C.
Most brasses melt in the 900-940 range. But "red" brass melts right around 1000 C. Copper melts at 1084 C and zinc at 419.5 C. Cupronickel melts between 1170 C and 1240 C. Nickel, at 1453 C. There are many alloys that form eutectic mixtures whose melting point is below that of the pure metals that comprise the alloy.

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Sorry, my statement was misleading and confusing. Of course you are right. I did not mean in alloys general but the alloys that are usually used underneath the coatings in electronic contacts from IT hardware. It is just an observation, I cannot say what these alloys are made of exactly (mostly copper of course, then zinc but also some tiny traces of exotic metals)
I try to narrow it by saying that I have observed the coatings to melt before the core of the contacts does, whatever alloy is used there.
Of course you are right, not ANY alloy has a higher melting point than silver/900 °C but the ones I used to try it out (mainly from memory sockets, pci sockets) seem to have a melting point higher and/or they simply need more time to change phase, so the gold or silver coating melted first and dropped down.

What I observed as well is that the purer gold is, the faster it melts. If there are impurities after AP->HCl/Cl process it takes much longer to melt and form a button.
So that is why I came to the conclusion that the gold from the plating melts faster than the rest of the metal, maybe even if their melting point is lower(!).
I dont know enough about the physics behind that but gold is the best heatconducting metal we play with, so maybe that plays a role.
The melting points and the heat that is exposed to the material is given and cannot be influenced.
But maybe (and this is my personal speculation) the better conductivity of gold and also silver makes it react faster and change the aggregate phase faster than the rest of the metal.

It is only a matter of seconds I am talking about! I have no reference, no link that I can give you. Just try it out and maybe you will also observe that the coating usually melts first, then drops down and gathers at the bottom of the material. Take away the heat, let it cool and watch how it has seperated.
But its enough, if you take the heat away at the right moment, to make the gold drop down.

Edit: All this needs tin and lead free contacts!!!

paulphil1 said:

I read somewhere on the web that a guy uses a torch to just melt the silver plating off of plated items such as silverware. The theory behind this I guess is that the melting temperature for silver is less than that of other typical metals that it is normally plated to. So I guess is that the silver just melts off and drips onto a surface and then can be collected for futher processing. Has anyone ever ever tried or heard of this. And yes, I know that many feel it is not economically feasible to worry about silver plated items, but I am just a hobbyist and not really concerned about the cost because I'm just playing around. I just want to know if this is a feasible idea. Thanks.

Paul

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I think your onto something here, any silver plate I've seen that has been through a house fire the silver is missing. Yup went up in smoke aka vapor like most metals will do when over heated.

If you could capture the vapor then re-condense it back into metal you have a winner. Truth is your energy costs will far exceed any values you'll ever get trying to recover silver in this manor.

Best way to recover silver from copper plate is via a copper cell your silver will collect as anode slimes. I would only attempt this on the hobby level should silver ever reach the $100.00 per tr mark. Otherwise sell your silver plate as number two copper scrap.

Running a copper cell is not all that difficult.

I had a situation that was unique and seeing this post reminded me of it. In welding I use copper bars as a backing for welding open areas of mild steel. A common practice. Electricians I worked with had extra buss bars and they were happy to keep them inter company and let me use them for welding, but these copper bars were coated with silver. I figured it would be no harm I just welded with it. During my weld which was vertical going up silver dripped off the bar through my rod flux I picted up splattered pieces around. Was strangest thing I could imagine. So seeing this I used a torch over the buss bar and was able to drip the silver into my catch bowl and capture the silver off of it. I don't believe every situation would work. But this instance it worked just dandy for me on Pure Copper coated with Silver. Before they scrap the copper now electricians let me get the silver off of the bars before they get wasted into copper scrap.

I believe it would work on flatware with chrome steel (rare, only quite new stuff - and it strips very fast, complete and easy in the cell) beneath the silver, if the silverlayer is very thick. I will find out, when I once will try to melt my left overs from electrolytic stripping.

If you heat up nickel-silver (a nickel bronze alloy that has no silver in it) that is plated with silver, you will see the silver bead up and roll away from the heated region. I've never tried to do it to a whole piece, but its kind of interesting to see and allows you to roughly gauge how thick the silver is plated. European flatware from what I have seen is plated way better than the average North American flatware I've seen. Nickel silver melts substantially hotter than silver.

Old european flatware can also be plated zinc.

A couple years ago i tried to melt the silver from a silver plated serving spoon to remove it. The base metal used in the spoon appeared to be copper and the silver did in fact melt but it would be nearly impossible to get it all off. Once the spoon was red hot the silver plating formed beads on the surface of the base metal and as you all know, there is not enough present on a piece of flatware to form a bead large enough to drip from the surface. I thing it could be done using a piece of steel wool while the silver is molten to "wipe" it off the surface and then the silver would have to be recovered from the steel wool. In my opinion, even as a hobby, it is not economically worthwhile to attempt silver recovery from plated materials. I will try to find the spoon i mentioned and post a picture of it.