Why not silver?

[T3sl4co1l]

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

[coppice]

Most of the wire used in defense applications is silver plated, for similar temperature tolerance reasons.

We 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.

Telfon 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.

[ArdWar]

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.

[soldar]

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 Sundays

https://www.voanews.com/a/spain-train-service-disrupted-by-theft-of-copper-cables-near-barcelona/7608212.html

Commuter 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.

[jzx]

They used silver for coils in isotope separators for the Manhattan project, bud they had good budgets.

There 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.

And 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.

[coppice]

Theft of copper wires is rampant in some parts of the world. Just imagine what it would be like with silver.

If you supply fibre optic cables to some markets it has to be printed, in appropriate languages "Optical cable. Contains no copper".

[David Hess]

Most of the wire used in defense applications is silver plated, for similar temperature tolerance reasons.

We 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.

Telfon 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.

The 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.

[coppice]

The 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.

PTFE 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.

[David Hess]

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 Sundays

https://www.voanews.com/a/spain-train-service-disrupted-by-theft-of-copper-cables-near-barcelona/7608212.html

Commuter 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.

In the US we are starting to have problems with copper thieves taking the charging cables from electric vehicle charging stations.

[coppice]

In the US we are starting to have problems with copper thieves taking the charging cables from electric vehicle charging stations.

There 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.

[AVGresponding]

In the US we are starting to have problems with copper thieves taking the charging cables from electric vehicle charging stations.

There 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.

With the scrap price of dry bright wire up around £7k/tonne, maybe not.

[tooki]

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.

Usually 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.)

[tooki]

The 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.

PTFE 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.

Yep, 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.

[IanB]

Yep, 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.

Alternatively, 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.

[tooki]

Yep, 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.

Alternatively, 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.

I 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.

[coppice]

I 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.

I 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.

[T3sl4co1l]

Yep, 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.

Alternatively, 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.

Well 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

[tooki]

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.

Indeed! 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!

[TimFox]

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.

Indeed! 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!

I have seen PTFE insulation turn to what looks like charcoal when in high-radiation areas.