Why not silver? - Page 1
Forum section: electronics / general

author: Connecteur
author_rank: Frequent Contributor
timestamp: June 12, 2024, 02:08:15 pm
content: Silver metal is one of the most efficient conductors of electricity. Imaging how much faster your device would charge through USB if it had silver wires. One trick Apple seems to have missed.Of course all of this is moot; silver is simply too expensive. Perhaps it shouldn't be, after the demise of the photographic film industry, which was likely the biggest industrial user of silver. Silver has become one of the precious metals of choice for financial speculation, even though there is really no tangible basis for it. Both silver and gold are very useful metals in electronics, and would probably be a boon to industry if they were cheaper, instead of being a medium of speculation as they currently are.The only way I see this changing, is if vastly abundant sources were somehow found. Seems unlikely, in this lifetime at least.

author: wraper
author_rank: Unknown
timestamp: June 12, 2024, 02:11:59 pm
content: Quote from: Connecteur on June 12, 2024, 02:08:15 pmYou could increase current by 5% for the same wire cross section.

author: dferyance
author_rank: Regular Contributor
timestamp: June 12, 2024, 02:39:09 pm
content: Charging efficiency isn't really a priority to anyone. The existence and popularity of wireless charging is what proves this. Wireless charging is incredibly inefficient.Keep in mind that power is voltage * current. It is possible to transfer more power by boosting the voltage and keeping current constant. Power transmission lines are an obvious example of this. They get by with aluminum + steel which is worse than copper. But they run high-voltage which reduces how much current needs to travel (also 3 phase but that is a different topic).USB PD already supports higher voltage charging. So USB cable resistance isn't really a limitation for charging. Battery cell construction and temperature tends to be a larger factor.Silver is great. It just isn't enough better than copper to justify the cost in most cases.

author: jzx
author_rank: Regular Contributor
timestamp: June 12, 2024, 05:28:58 pm
content: They used silver for coils in isotope separators for the Manhattan project, bud they had good budgets.Sometimes silver is used in rf applications, to have better Q in coils, less resistance.But it is expensive. For a faster charge of your phone, you can use USB C with an higher voltage. With more volts, resistance is less important.

author: wraper
author_rank: Unknown
timestamp: June 12, 2024, 05:34:46 pm
content: Conductivity difference with copper is marginal. There is more tolerance in cross section of usual wire than cross section/resistance advantage silver would offer.

author: chilternview
author_rank: Frequent Contributor
timestamp: June 12, 2024, 05:45:10 pm
content: You could use it for all those high voltage DC power lines round the country. At 400kV it would be more difficult to steal

author: zilp
author_rank: Frequent Contributor
timestamp: June 12, 2024, 09:31:55 pm
content: Quote from: jzx on June 12, 2024, 05:28:58 pmIt's not so much that they had a good budget, but that there was a copper shortage, and that the treasury happened to have a few thousand tons of silver lying around that they could borrow ... which is what they did.

author: David Hess
author_rank: Super Contributor
timestamp: June 12, 2024, 10:22:17 pm
content: Quote from: jzx on June 12, 2024, 05:28:58 pmThere was a copper shortage because the copper was going into brass for fixed ammunition.During the war, they also pulled the copper bus bars out of the powerhouses along the Columbia river and replaced them with silver bus bars, guarded by men with guns, and it was not for greater efficiency. They simply needed the copper for the war.

author: coppice
author_rank: Super Contributor
timestamp: June 12, 2024, 10:33:19 pm
content: Quote from: zilp on June 12, 2024, 09:31:55 pmThey borrowed it, and at the end of the war they returned it with a small interest. The story of this is really interesting. When the workers realised how must silver they were handling each day, pilfering apparently exploded, and they had to run a tight security regime to stop it all disappearing.

author: coppice
author_rank: Super Contributor
timestamp: June 12, 2024, 10:35:52 pm
content: Silver is widely used as a conductor, in very thin films, for RF applications. When the skin depth get really low you need the lowest skin resistance possible, but the bulk of the conductor, carrying only DC, can still be copper.

author: coppercone2
author_rank: Super Contributor
timestamp: June 12, 2024, 10:38:21 pm
content: i wonder how good it is for magnet wire and stuff like that. like mechanically

author: TimFox
author_rank: Super Contributor
timestamp: June 12, 2024, 11:17:25 pm
content: Also note that aluminum, which has lower conductivity than copper, is often used for conductors in long transmission lines (usually at high voltage) instead of copper due to its lower weight for a given resistance.Conductivity: Cu/Al = 1/0.61 = 1.64:1Volume density: Cu/Al = 8.94/2.70 = 3.31:1If weight is the only issue, then aluminum wins.Different applications, such as transformers, depend more on the volume of the conductor for a given resistance, and copper is preferred.Mixing aluminum and copper is a well-known hazard.General reference:https://www.wilsonpowersolutions.co.uk/app/uploads/WPS_Aluminium-v-Copper_white-paper_-2021.pdf

author: David Hess
author_rank: Super Contributor
timestamp: June 12, 2024, 11:21:09 pm
content: Quote from: coppercone2 on June 12, 2024, 10:38:21 pmAs far as I know, silver works just as well as copper for wire. Teflon insulated copper wire uses silver plating instead of tin plating because the lower melting point of tin would defeat using Teflon in high temperature applications. The audio fanatics sometimes use silver wire and silver wire transformers for its 5% improvmenet, and I have not heard of any problems with that.

author: coppice
author_rank: Super Contributor
timestamp: June 12, 2024, 11:21:26 pm
content: Quote from: TimFox on June 12, 2024, 11:17:25 pmWeight and cost. If you wanted to make major distribution cables from copper the demand would drive its cost and availability into a very dark place.

author: coppice
author_rank: Super Contributor
timestamp: June 12, 2024, 11:22:48 pm
content: Quote from: David Hess on June 12, 2024, 11:21:09 pmMost of the wire used in defence applications is silver plated, for similar temperature tolerance reasons.

author: coppercone2
author_rank: Super Contributor
timestamp: June 12, 2024, 11:25:02 pm
content: but as far as ripping and work hardening etc?

author: SiliconWizard
author_rank: Super Contributor
timestamp: June 12, 2024, 11:48:36 pm
content: We make bullets out of silver and this is a very effective conductor of BS.Jokes aside, as others have said. Benefits relatively marginal apart from niche applications, and too expensive. Weight also as the density of silver is ~17% higher than that of copper.

author: coppercone2
author_rank: Super Contributor
timestamp: June 12, 2024, 11:53:45 pm
content: maybe it can make a stronger pen drill.you know it is more thermally conductive. a potted winding might be able to really dissipate more heat.you get 5% less resistance and 5% higher thermal conduction. for a motor that might mean something if heat burried deep can get out quicker. it might translate to a substantial performance increase. IDK what the net effect of both is. You would have to rewind a motor.

author: vk6zgo
author_rank: Super Contributor
timestamp: June 13, 2024, 12:07:54 am
content: Quote from: jzx on June 12, 2024, 05:28:58 pmRF coils are often silver plated copper, which is just as effective as solid silver, due to "skin effect".There is a caveat with silver plating----the plating solutions used for normal decorative purpose are optimised for lustre & durability in use, so contain specially selected impurities to achieve those ends.Unfortunately, those impurities increase the resistivity of the deposited silver, so special solutions must be used for RF purposes.

author: Circlotron
author_rank: Super Contributor
timestamp: June 13, 2024, 12:23:51 am
content: Quote from: David Hess on June 12, 2024, 10:22:17 pmOf topic, so let's not get too sidetracked, but why is brass used for ammunition? Why not plain old cheap steel?And when a war is finished, scrap metal scroungers must have a field day.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 13, 2024, 12:55:49 am
content: Brass is formed several times for ammunition: deep drawn to forge a solid thick base with thin walls; rolled or swaged to hold the bullet; and one last time, when it's actually fired, to expand into and seal the breech of the barrel. It has an excellent combination of formability, machinability, ductility, strength, and also lubricity to move smoothly through the mechanism, and corrosion resistance to survive years in the field and remain usable.I think blanks would still need to be annealed once or twice on the way through deep drawing? But maybe they can manage it in one hit. Huh, come to think of it, I've never looked up an ammunition manufacturing video. Let me see......Or even just an article, that'll do. Looks like four anneals total:https://www.petersoncartridge.com/technical-information/drawing-brass/For a rifle cartridge anyway; maybe a pistol round only needs three, maybe even two, but three more likely.Brass can even be reused once, maybe even twice or more, if it's clean and not dented, and probably many times with additional annealing and swaging steps to keep it in tolerance.Steel might be too strong, having difficulties in forming a thin shape, or fitting the bullet without turning up burrs (it's only soft lead, or copper jacketed, after all), or not conforming to the barrel well enough on firing, and obviously is prone to rusting. Hmm, I see plenty of hits for steel rounds, so it's definitely used, and many of those issues might be mitigated say by lacquer to improve lubricity and corrosion resistance, but given the quoted text on most hits, it seems it tends to be poor quality, loose tolerance, "dirty", etc. That kind of goes with it being cheaper in general, but perhaps that also speaks to manufacturing variation due to material differences. Steel is quite ductile, but not as much as copper and alloys are; it probably needs one or two additional annealing steps to complete (and higher temperature is required to anneal steel). Or maybe they manage with a less strenuous process, like rolling seamless tube down to shape, but maybe that only works with certain types of bases.I'm quite removed from gun lore, myself; this is more motivated by the metallurgical relevance. Others can chime in with actual practice.On a related note, I wouldn't at all mind tin-plated steel crimp terminals, for connectors carrying signals; it should be workable, and perhaps they could be cheaper, or the higher strength allows more flex and thus vibration resistance, or contact pressure (but then again, it can't be too high where the tin plating gets squidged out), so there could be reliability gains; but probably between the ductility, and the dissimilarity to the wire it's crimped on (crimping pressure/depth needs to be more carefully calibrated to avoid pinching through the wire entirely), this just isn't a good idea. But maybe they do indeed use it some places, dunno.Tim

author: xrunner
author_rank: Super Contributor
timestamp: June 13, 2024, 12:57:00 am
content: Yes steel is used for ammo -https://ammo.com/casing-type/steel

author: coppercone2
author_rank: Super Contributor
timestamp: June 13, 2024, 01:00:46 am
content: steel anything instead of brass is like soviet crap IMO.Like steel connectors. I don't mean some fancy stainless. The soviet union loved making things out of steel.THink you can get a bronze or brass heat exchanger for your car? nope, it was cast iron. at least i suspect so.steel vacuum cleaners too.

author: TimFox
author_rank: Super Contributor
timestamp: June 13, 2024, 01:15:25 am
content: Quote from: David Hess on June 12, 2024, 11:21:09 pmThe temperature used to fuse Teflon to stranded wire during manufacture would melt tin (on tinned strands), thus losing the flexibility of stranded wire.Most Teflon-insulated copper wire is therefore silver-plated, although some is unplated.

author: David Hess
author_rank: Super Contributor
timestamp: June 13, 2024, 03:51:30 am
content: Quote from: coppice on June 12, 2024, 11:22:48 pmWe used Teflon insulated silver plated wire already because we had assemblies which had to be baked at higher temperatures, but when we did some military contracts, the military really liked that type of wire even when it was not necessary.Incidentally Teflon insulated wire is not a panacea. UV (and ozone?) will apparently degrade Teflon, and abrasion can be a problem.Quote from: Circlotron on June 13, 2024, 12:23:51 amSteel did get used when they got desperate, but it is more difficult to form and use. Aluminum can also be used but again, is more difficult to work with. Brass has a really good combination of ductility and work hardening for cartridge cases.After World War 2, areas that had large tank battles were mined for the tank ammunition penetrators which often used expensive tungsten alloys.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 13, 2024, 11:26:48 am
content: Nickel plating also popular, I have some MIL spec "mineral filled PTFE" in 10AWG like this. Tight build, it's made in alternating spiral layers, not just random strands; and with that nickel plating, it's a right bitch to tin, definitely better suited to crimping, lol.Tim

author: coppice
author_rank: Super Contributor
timestamp: June 13, 2024, 12:00:29 pm
content: Quote from: David Hess on June 13, 2024, 03:51:30 amTelfon insulated wire was a big thing for airborne use in the early 70s, for its temperature tolerance. Then it was banned from all uses except RF, because of its extreme toxicity when it gets hot enough. We had to use things liek ETFE instead, which is a horrible material for insulation, as it just loves to crack.

author: ArdWar
author_rank: Frequent Contributor
timestamp: June 13, 2024, 12:33:59 pm
content: OP's proposal sounds like what happen when someone stumble upon a parametric table, sort it by a single column, pick topmost result, ignore everything else, and shouting why everything isn't made out of it.Fun fact: If you're mains utility consumer, I'm pretty sure your electricity spend 90+% of its lifetime flowing through aluminum wire instead of copper. A much worse conductor than copper. I'll leave it to OP to figure out why it isn't using copper, let alone silver. I'll give you a head start so we'll only talk about technical characteristics and not even talking about cost or abundance here.

author: soldar
author_rank: Super Contributor
timestamp: June 13, 2024, 01:02:22 pm
content: Theft of copper wires is rampant in some parts of the world. Just imagine what it would be like with silver.In Spain the theft of copper wires happens every day and twice on Sundayshttps://www.voanews.com/a/spain-train-service-disrupted-by-theft-of-copper-cables-near-barcelona/7608212.htmlCommuter rail service for Barcelona and northeastern Spain has suffered major disruption because of the theft of copper cables from a train installation, Spanish rail authorities said Sunday.Thousands of commuters were stranded at train stations in and around Barcelona after trains couldn't run on several commuter lines.Catalonia’s commuter rail service suffers regular delays, some because of similar acts of theft.

author: jzx
author_rank: Regular Contributor
timestamp: June 13, 2024, 01:42:16 pm
content: Quote from: David Hess on June 12, 2024, 10:22:17 pmAnd also silver allowed more current in the coils of separators and stronger magnetic fields. I dont know, but I think that they used because they needed that difference. Perhaps the reason was only the shortage of copper.In the case of aluminium, copper has less reistance by section, but aluminiun less by weight, if I am not wrong.If you want to hang the wires in poles, aluminium is better and cheaper.In the case of OP, you almos always can reduce the resistance with a fatter wire, for you usb cable, putting 5% bigger section you can have the performance of silver. Many usb cables are crap whith very thin wires.

author: coppice
author_rank: Super Contributor
timestamp: June 13, 2024, 02:13:51 pm
content: Quote from: soldar on June 13, 2024, 01:02:22 pmIf you supply fibre optic cables to some markets it has to be printed, in appropriate languages "Optical cable. Contains no copper".

author: David Hess
author_rank: Super Contributor
timestamp: June 13, 2024, 03:11:45 pm
content: Quote from: coppice on June 13, 2024, 12:00:29 pmThe abrasion problem came from aircraft operations also. I think Bob Pease reported the problem with UV or ozone in an article discussing why using Teflon as an insulator everywhere can cause more problems than it solves.I really like Teflon for coaxial cable because it makes it much easier to solder without melding the dielectric, and the outer insulation on Teflon coaxial cable, whatever plastic the use, is really tough.

author: coppice
author_rank: Super Contributor
timestamp: June 13, 2024, 03:17:19 pm
content: Quote from: David Hess on June 13, 2024, 03:11:45 pmPTFE abrasion is usually less of a problem than flowing. Any pressure applied to PTFE insulation causes it to slowly deform, and can eventually expose the conductor it protects to whatever is applying the pressure.

author: David Hess
author_rank: Super Contributor
timestamp: June 13, 2024, 03:20:33 pm
content: Quote from: soldar on June 13, 2024, 01:02:22 pmIn the US we are starting to have problems with copper thieves taking the charging cables from electric vehicle charging stations.

author: coppice
author_rank: Super Contributor
timestamp: June 13, 2024, 03:26:16 pm
content: Quote from: David Hess on June 13, 2024, 03:20:33 pmThere are lots of reports of that happening in the UK, too. They are high current cables, but only a few metres long. It feels more like a prank crime that a profit driven one.

author: AVGresponding
author_rank: Super Contributor
timestamp: June 13, 2024, 05:14:28 pm
content: Quote from: coppice on June 13, 2024, 03:26:16 pmWith the scrap price of dry bright wire up around £7k/tonne, maybe not.

author: tooki
author_rank: Super Contributor
timestamp: June 13, 2024, 05:22:52 pm
content: Quote from: David Hess on June 13, 2024, 03:11:45 pmUsually FEP, but some are PVC, some are Teflon, some PFA.(I terminated a lot of RG-196, which is basically RG-178 but with Teflon jacket instead of FEP, when I worked at the physics department, for several things that involve both cryogenic temperatures and high vacuum, where Teflon is one of the preferred materials.)

author: tooki
author_rank: Super Contributor
timestamp: June 13, 2024, 05:26:16 pm
content: Quote from: coppice on June 13, 2024, 03:17:19 pmYep, PTFE is terrible under pressure. I discovered recently that there exist PTFE o-rings and gaskets, made for the chemical and pharmaceutical industries, which use mineral fillers to create cold-flow-resistant PTFE that can be used for compression seals. They also have some that are pure PTFE that is somehow modified to make it resist cold flow deformation.

author: IanB
author_rank: Super Contributor
timestamp: June 13, 2024, 05:38:30 pm
content: Quote from: tooki on June 13, 2024, 05:26:16 pmAlternatively, PTFE is really good under pressure. When used as plumber's tape, it flows to fill in any gaps and thereby creates a good seal.In material science, "good" and "bad" depend very much on the desired function and application of the material.

author: tooki
author_rank: Super Contributor
timestamp: June 13, 2024, 05:50:07 pm
content: Quote from: IanB on June 13, 2024, 05:38:30 pmI wonder if there are meaningful differences in the type of PTFE used, with regards to cold flow -- for one thing, there are different kinds of PTFE (since the polymer chains can be different lengths), but it also may depend on how it's processed. PTFE tape feels and behaves quite differently from, say, PTFE sheeting or blocks. (PTFE sheeting is often made by skiving a block of it, which I find amusing.) PTFE electrical insulation can be monolithic (extruded or something), or wrapped (built up by wrapping PTFE tape). The RG-196 I mentioned earlier is interesting, because it uses monolithic PTFE for the dielectric, but wrapped PTFE for the jacket.

author: coppice
author_rank: Super Contributor
timestamp: June 13, 2024, 05:54:13 pm
content: Quote from: tooki on June 13, 2024, 05:50:07 pmI believe its mostly about filler. The pure PTFE in RF coax and plumbers tape are the flowiest. The stuff in a frying pan is heavily filled with stone powder to make it tough, and it displays no fluid qualities.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 13, 2024, 06:06:35 pm
content: Quote from: IanB on June 13, 2024, 05:38:30 pmWell yeah, horses for courses. And of course this thread is about wire, where creep is generally undesirable.Pure PTFE can probably be crosslinked; hmm, ah yeah, with e-beam or gamma for example, it seems. Apparently this is a relatively recent discovery ('90s), the trick is doing it near the melting point, otherwise radiation just kind of crumbles it molecularly speaking. Neat.Tim

author: tooki
author_rank: Super Contributor
timestamp: June 13, 2024, 06:31:11 pm
content: Quote from: T3sl4co1l on June 13, 2024, 06:06:35 pmIndeed! My old boss is working on some stuff for CERN, and while PTFE is a go-to insulation for tons of physics applications, on that one he's had to find other things because the radiation it would get exposed to would ruin PTFE in short order!

author: TimFox
author_rank: Super Contributor
timestamp: June 13, 2024, 08:52:35 pm
content: Quote from: tooki on June 13, 2024, 06:31:11 pmI have seen PTFE insulation turn to what looks like charcoal when in high-radiation areas.