Teflon plated silver wire? - Page 1
Forum section: electronics / beginners

author: kalel
author_rank: Frequent Contributor
timestamp: September 30, 2017, 12:52:54 am
content: I ran into this "teflon plated silver wire"Cost seems to be 0.84 per meter.QuoteThey show the image of a computer power supply using these (they mention customers mod it themselves), but I'm not sure that some heat resistant wire is necessary for that. I mean, if it heats up too much (so much that there's some bad effect you can notice), there's probably something wrong with the PSU or the system. Perhaps some more expensive units use these silver teflon plated wires.What are the realistic uses for these type of wires? Considering that specifications are correct.

author: Circlotron
author_rank: Super Contributor
timestamp: September 30, 2017, 01:36:25 am
content: If you are building something for art’s sake as well as function, and you like the ascetics of fancy materials then I think that’s a valid application. Or maybe the next Mars rover? But expecting it to give some improvement in function? Nahhhh....

author: ataradov
author_rank: Super Contributor
timestamp: September 30, 2017, 01:42:43 am
content: Here is one good use:https://www.eevblog.com/forum/projects/restoring-an-old-computer-neat-trick-for-prototypers/new/

author: kalel
author_rank: Frequent Contributor
timestamp: September 30, 2017, 02:02:41 am
content: Quote from: ataradov on September 30, 2017, 01:42:43 amSounds like we should be careful with some of that wire.

author: vk6zgo
author_rank: Super Contributor
timestamp: September 30, 2017, 02:14:48 am
content: Well, as you cannot "plate" Teflon, it is really " Teflon coated silver plated copper wire".That said, I have some nice multi-strand silver plated wire out of a Siemens TV Transmitter power supply( rescued from the junk bin).It isn't Teflon coated, though, but it is very easy to solder &, if used outside, stands up to weather better than plain copper.

author: edpalmer42
author_rank: Super Contributor
timestamp: September 30, 2017, 02:53:56 am
content: It's very common to find Teflon-insulated silver plated copper wire in military equipment. You can buy it by the foot on ebay in almost any gauge you want. The Teflon has a high temperature rating and is impervious to many chemicals that will rot something like PVC.Silver plating is also common in RF voodoo work. It improves the performance of any resonant enclosure like a cavity or interdigital filter.And, as vk6zgo stated, they've got the wording wrong. It's not 'Teflon plated silver wire'. It isn't clear exactly what it is. It could be 'Teflon insulated silver wire' or, more likely, it's 'Teflon insulated silver plated copper wire'.Of course, none of this is going to have any effect in a computer.Ed

author: KL27x
author_rank: Super Contributor
timestamp: September 30, 2017, 05:09:11 am
content: Almost all Kynar insulated "wire wrap" wire is silver plated. It wets like it's fluxed. I'm not sure why silver plated wire doesn't oxidize like mad, though. Seems like silverware tarnishes quite quickly.Teflon insulated wire can be a pain to strip. It doesn't like to separate/rip at a fracture point. And it's slippery as heck, which makes it hard to strain relieve, properly. I wouldn't say I avoid it like the plague. But the initial small samples of this military grade wire I purchased 10 years ago has not run out, yet.

author: orin
author_rank: Frequent Contributor
timestamp: September 30, 2017, 05:40:14 am
content: FWIW, teflon insulated stranded hook-up wire is silver plated because at the temperature at which it is extruded; 'tin' plating would melt and you'd end up with a solid conductor. Look up the melting point of tin, silver and teflon... or do a google search on "pease teflon silver wire".

author: ataradov
author_rank: Super Contributor
timestamp: September 30, 2017, 05:42:41 am
content: That Soviet wire that I use is pure copper, but it is not extruded, the insulation is clearly wrapped from a number of very thin teflon strips. I guess Soviets were a bit careful about their silver

author: edpalmer42
author_rank: Super Contributor
timestamp: September 30, 2017, 06:12:30 am
content: Quote from: KL27x on September 30, 2017, 05:09:11 amAFAIK, silver tarnishes due to the presence of trace amounts of sulphur compounds in the air. They could come from a nearby oil refinery or the eggs you cooked this morning. If the insulation on the wire prevents the air from getting to the silver, it can't tarnish.Ed

author: vk6zgo
author_rank: Super Contributor
timestamp: September 30, 2017, 07:18:49 am
content: Quote from: edpalmer42 on September 30, 2017, 02:53:56 amA cautionary note:-Not all silver plating is the same.The stuff used in Commercial plating shops for medals, trophies, & domestic silverware is optimised for appearance, ease of polishing, & durability.To this end, various impurities are added to the plating solution.During the early years of Radio, this was not the case, & ordinary silver plating was quite pure, so that thepromised decrease in losses actually occurred.By the 1950s, the Commercial mix had changed, but "silver plating to decrease losses" was still "received wisdom" among RF folks.In the later years of that decade, two EEs published (in the "Telecom Journal of Australia") the results of their testing with plain copper-v- ordinary commercial silver plating.They found that the former was less lossy at RF.

author: David Hess
author_rank: Super Contributor
timestamp: September 30, 2017, 12:11:07 pm
content: Besides military and aerospace applications, Teflon insulated wire is commonly used in high temperature commercial and industrial applications. I have run across it in hot plates before.I have found it more difficult to work with than Kynar insulated wire which has better mechanical properties anyway. Somewhere I read that when they first started using it in aircraft, they had reliability problems from flowing and abrasion before figuring out how to use it safely.I really like RG-316 coaxial cable in place of RG-174 though because the Teflon insulation means it can be soldered without melting.

author: ChrisLX200
author_rank: Unknown
timestamp: September 30, 2017, 12:15:12 pm
content: Take Teflon above soldering temperatures - burn it - and it releases some very nasty gases (e.g., phosgene) so I would avoid using it for anything that could potentially overheat.ChrisH

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: September 30, 2017, 03:00:00 pm
content: Quote from: David Hess on September 30, 2017, 12:11:07 pmRG-316 uses an FEP jacket, RG-188 is the one with a PTFE jacket.

author: vk6zgo
author_rank: Super Contributor
timestamp: September 30, 2017, 03:24:33 pm
content: Quote from: ChrisLX200 on September 30, 2017, 12:15:12 pmI have worked with equipment faults which caused burning of Teflon.Yes, there was a "funny smell", but the quantities released are extremely small.Such faults affecting Teflon in this way is not at all uncommon, yet over many years in this field, I have never heard of anybody harmed by burning of this material.

author: amyk
author_rank: Super Contributor
timestamp: September 30, 2017, 03:42:11 pm
content: Decomposition products of Teflon (and other fluorinated substances) include hydrofluoric acid. That is very toxic.I can see how a few mg would probably be OK, but lots of people have been killed or seriously injured in large fires involving bigger amounts. For example, I have a lot of automotive manuals that warn against incineration of Teflon parts.

author: JacobPilsen
author_rank: Regular Contributor
timestamp: September 30, 2017, 06:29:20 pm
content: Teflon contains FluorinePhosgene contains Chlorine...Some transmutation ???

author: kalel
author_rank: Frequent Contributor
timestamp: September 30, 2017, 07:26:31 pm
content: What makes me cautious is this thread:https://www.eevblog.com/forum/projects/restoring-an-old-computer-neat-trick-for-prototypers/new/It mentions some issues starting with slippery feeling.

author: ChrisLX200
author_rank: Unknown
timestamp: September 30, 2017, 07:59:03 pm
content: Quote from: JacobPilsen on September 30, 2017, 06:29:20 pmDifluorophosgene CF2O is toxic and one of the breakdown products...There are other nasties:https://www.fluoridealert.org/wp-content/pesticides/teflon.decomposition.prod.htmChrisH

author: David Hess
author_rank: Super Contributor
timestamp: October 01, 2017, 12:06:47 am
content: Quote from: radar_macgyver on September 30, 2017, 03:00:00 pmBut it is the melting polyethylene dielectric in RG-174 which makes it difficult to solder.

author: Cerebus
author_rank: Super Contributor
timestamp: October 01, 2017, 12:19:04 am
content: Quote from: kalel on September 30, 2017, 07:26:31 pmFollow the links for that and it seems to be anecdotally attributed to molybdenum poisoning due to a molybdenum compound admixed with the PTFE. However, a quick literature search suggests that molybdenum has low toxicity in humans; low enough that it has been difficult to calculate exposure limits for industry.In other words, this is not a reliable source to cite for the purported hazards of PTFE.

author: kalel
author_rank: Frequent Contributor
timestamp: October 01, 2017, 12:21:35 am
content: Quote from: Cerebus on October 01, 2017, 12:19:04 amFortunately I don't have any need for special types of wire, I was just wondering what the advantages might be. I didn't realize the potential caution needed. For those government projects or whatever company uses it, they will already know the hazards where present and have safety gear if needed, so they will have little or no problems.

author: Cerebus
author_rank: Super Contributor
timestamp: October 01, 2017, 12:27:51 am
content: Quote from: ChrisLX200 on September 30, 2017, 07:59:03 pmSomehow the "Fluoride Action Network" doesn't immediately suggest somewhere one would go for accurate, independent, impartial, scientific advice on fluorine compounds.

author: Cerebus
author_rank: Super Contributor
timestamp: October 01, 2017, 12:39:23 am
content: Quote from: kalel on October 01, 2017, 12:21:35 amThere is no need for "potential caution". PTFE is one of the most chemically stable polymers you will encounter - that's why it is good for the many purposes it is used for. The last time you had something fired in a frying pan there's a good chance that it was PTFE coated (Teflon, non-stick). If I was going to be concerned, I would be much more concerned about the breakdown products from soldering ordinary everyday PVC coated wire than I would ever be about soldering or handling PTFE coated wire. PTFE is used in surgical implants, that's how dangerous it is to handle.Really folks, I don't expect fact free scaremongering about 'chemicals' (which is what this is) amongst a bunch of engineers.

author: amyk
author_rank: Super Contributor
timestamp: October 01, 2017, 12:51:01 am
content: There is no "scaremongering" here, just cautions that Teflon is inert until heated to high temperatures --- at which point it gives off very toxic decomposition products.Quote from: edavid on September 30, 2017, 03:49:19 pmhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC1848435/pdf/canmedaj00914-0042a.pdfhttps://www.ncbi.nlm.nih.gov/pubmed/2922720

author: Cerebus
author_rank: Super Contributor
timestamp: October 01, 2017, 01:09:56 am
content: Quote from: amyk on October 01, 2017, 12:51:01 amIt is scaremongering when it leads to people gaining the impression that they need to be careful merely handling PTFE as at least one commenter has said.It is pretty much common sense that combustion or heat decomposition products ofanythingare likely to be harmful, PTFE is neither unique nor particularly especially harmful in that context. Like I said, the risks of soldering PVC coated wire (lower melting point, lower decomposition temperature, equally nasty decomposition products) are probably higher than soldering PTFE coated wire, and I bet a goodly number of folks here solder PVC coated wire on a daily basis without a second thought.

author: nanofrog
author_rank: Super Contributor
timestamp: October 01, 2017, 03:21:21 am
content: FWIW, there isn't an issue of off-gassing anything toxic if it's soldered properly as the insulation doesn't get hot enough to release anything dangerous IME (i.e. a couple of seconds or so). At least this is what I experienced in the aerospace industry with the few joints that were soldered rather than crimped. Wire-loom work was increased around soldered connections vs. crimped connections in order to reduce the failure at the solder joint IME (solder joint vs. crimped in regard to work-hardening & subsequent failure).

author: KL27x
author_rank: Super Contributor
timestamp: October 01, 2017, 03:49:34 am
content: QuoteI imagine this is something akin to wrapping or at least bending the wires around posts, close to the connection, as a strain relief?

author: nanofrog
author_rank: Super Contributor
timestamp: October 01, 2017, 11:58:29 am
content: Quote from: KL27x on October 01, 2017, 03:49:34 amYes. It was done to restrict movement at the point solder began/stopped to prevent breakage (i.e. work hardening due to vibration).