Gold contact surfaces, CAT6, improvement with gold amalgam - Page 1
Forum section: electronics / general

author: NCG
author_rank: Regular Contributor
timestamp: October 19, 2024, 11:39:29 am
content: Having CAT6 in high vibration environment, gold plated pins - would additional small amount of gold/mercury amalgam improve the contact? Naturally, selecting better connectors and redesign would be the long term solution but would this approach improve the reliability for the existing devices in our opinion? Small enough amounts of the amalgam should not to destroy the mechanical properties of the pin, initially there is liquid metal contact and after evaporation of mercury fused together gold joint, with minimal if any changes in structure.

author: nctnico
author_rank: Super Contributor
timestamp: October 19, 2024, 11:41:48 am
content: I'd strongly advise against using mercury as it is toxic. You might contaminate all the equipment further needing it to be replaced entirely due to health and safety issues.And mercury doesn't evaporate at room temperatures (fortunately)but it does like to react with other metals.Edit: applied tooki's correction below

author: tooki
author_rank: Super Contributor
timestamp: October 19, 2024, 12:00:46 pm
content: Quote from: nctnico on October 19, 2024, 11:41:48 amWhat?!? It most certainly does evaporate at room temperature!!! Mercury vapors are a recognized hazard of mercury spills!

author: Gyro
author_rank: Super Contributor
timestamp: October 19, 2024, 12:05:34 pm
content: Most metals will form an amalgam with Mercury, the most common exceptions are Iron and Tungsten, so your confidence in the Mercury not affecting the contact base material properties is unfounded.Yes, Mercury easily forms an amalgam with Gold, but the Gold flash on the contacts is very thin (low volume) so it will very quickly be through to amalgamating with the base material. To evaporate the Mercury from the Mercury amalgam (apart from being dangerous) requires high (flame type) temperatures, it will persist in the connector, slowly destroying the mechanical properties of the contacts.The secret to connectors in high vibration environments is to mechanically clamp the connector cable to the vibrating chassis so that the vibration isn't being imposed across the contacts. You should also test to make sure there aren't any vibrational modes at the relevant frequenc(ies) in the length of cable between the clamp and connector.Fundamentally, your idea is mad.

author: tooki
author_rank: Super Contributor
timestamp: October 19, 2024, 12:22:12 pm
content: Quote from: NCG on October 19, 2024, 11:39:29 amThat sounds like a spectacularly bad idea to me.You’d start off with a good connection and then vibration would break it apart later, leaving you with a joint with undefined properties. Not to mention the high risk of causing short circuits when applying it. (I assume that by CAT6 you mean CAT 6 cable with RJ-45 connectors.)You could use adhesive to secure the plugs after insertion. (Hot glue would work if you want to be able to remove it later, since hot glue releases cleanly with just alcohol. For permanent support, use electronics-safe silicone or SMP (silane modified polymer) adhesive/sealant.) You could also apply a contact grease to the contacts to reduce wear during vibration, but make sure it is one optimized for gold. This would reduce contact fretting, too. (Gyro, please correct me if I’m wrong!)

author: Gyro
author_rank: Super Contributor
timestamp: October 19, 2024, 12:51:36 pm
content: Quote from: tooki on October 19, 2024, 12:22:12 pmSounds ok to me. The fundamental goal is to eliminate as much relative movement as possible though - yes, hot glue ought to help as a non-destructive 'immobilizer' to back up a properly clamped cable.

author: NCG
author_rank: Regular Contributor
timestamp: October 20, 2024, 12:18:56 pm
content: Few additional comments on theme:*It is already known, that gluing the connector shells together did not work (at least with semi-rigid compounds).*Connectors are in closed, nitrogen purged environment, so toxicity is minimal concern.*Mercury slip rings are known to work in power delivery systems.*No concerns of shorting with suitable application method and amounts of the amalgams.The composition of amalgam can be selected (gold percentage), however still maybe Cerrolow 117 or Fields metal as basis for soldered together contacts would be better than amalgam.

author: Gyro
author_rank: Super Contributor
timestamp: October 20, 2024, 01:18:03 pm
content: Now why didn't you include that information in your original post?

author: Kjelt
author_rank: Super Contributor
timestamp: October 20, 2024, 04:09:39 pm
content: Quote from: NCG on October 19, 2024, 11:39:29 amI would focus my energy time and money on that

author: NCG
author_rank: Regular Contributor
timestamp: October 21, 2024, 04:33:21 am
content: Quote from: Kjelt on October 20, 2024, 04:09:39 pmI would focus my energy time and money on thatGenerally - yes. Still, if suitable method for standard CAT6 can be found, it avoids significant additional energy and time spent on existing equipment. I am quite surprised about the low robustness of RJ45. What is the go to alternative, GEMnet or something else?

author: NCG
author_rank: Regular Contributor
timestamp: October 21, 2024, 04:39:38 am
content: Quote from: Gyro on October 20, 2024, 01:18:03 pmTo not to limit the breath of answers?

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: October 21, 2024, 05:15:41 am
content: Industrial Ethernet uses M12 (X-code) connectors that have a threaded shell and are specified to work in a high vibration environment. For a price, one can get Ethernet switches with M12 ports.

author: jonpaul
author_rank: Super Contributor
timestamp: October 21, 2024, 05:52:19 am
content: IDC connectors are gas tight.Used in telecom for over 70 yrsj

author: Kjelt
author_rank: Super Contributor
timestamp: October 21, 2024, 08:26:29 am
content: Quote from: NCG on October 21, 2024, 04:33:21 amI am not, it was "designed" as ultra low cost consumer grade connector derived from the RJ11telephone connectors.I am surprised it was adopted for industrial grade equipment, ethercat etc.And the standard practice was to have a cable gutter or cable rest in front of the connectors to mechanically tie the cables to add strain relief to the connector.Noone seems to do that anymore, result: the cable "pulls" on the connector.

author: tooki
author_rank: Super Contributor
timestamp: October 21, 2024, 08:48:18 am
content: Quote from: NCG on October 21, 2024, 04:39:38 amSo that you waste everyone’s time (oursand yours) with answers that have either already been tried or aren’t applicable?

author: NCG
author_rank: Regular Contributor
timestamp: October 21, 2024, 09:14:21 am
content: Quote from: tooki on October 21, 2024, 08:48:18 amQuite an opposite - clearly boxed question will clearly limit the scope of answers. Thus far no-one has not even hinted of the widely spread substandard RJ45 connector problem, conductive glues, solderable drop in replacements for standard RJ45 terminals or anything that quite possibly can be brilliant solution for not only me, but for others.

author: NCG
author_rank: Regular Contributor
timestamp: October 21, 2024, 09:22:13 am
content: Quote from: radar_macgyver on October 21, 2024, 05:15:41 amThat is interesting find, will check it out for sure. The Advantech EKI-2528I-M12 seems cheap and is IP67 but limited to 100Mbit.https://www.advantech.com/emt/products/05b4ad62-1b78-4622-94ef-5acfea07cd5c/eki-2528i-m12/mod_84dff228-afca-493d-87d6-c5dc3a72766f

author: tooki
author_rank: Super Contributor
timestamp: October 21, 2024, 09:40:25 am
content: Quote from: NCG on October 21, 2024, 09:14:21 amUm, yeah. That’s the point. There is no value in irrelevant answers.Look, dude, take it from those of us who are forum veterans (not just on this forum, but others too): detailed problem descriptions get you better answers. Not only do they prevent people from wasting time on irrelevant answers, it makes people creative about ways to solve the problem.Though it is written with IT questions in mind, the following article is something everyone should read:http://www.catb.org/esr/faqs/smart-questions.htmlQuote from: NCG on October 21, 2024, 09:14:21 amBecause itisn’ta widespread problem. Millions (if not billions) of those connectors are in active use for their intended purpose without problems. They were not designed for high-vibration environments, so you shouldn’t be using them there, and you certainly can’t call them “substandard” because they don’t perform well in an application they were not designed for!Quote from: NCG on October 21, 2024, 09:14:21 amMaybe that’s because those things either don’t exist or are terrible ideas.It wouldn’t make sense to design a drop-in-replacement RJ45 connector because you’d be dropping it into a design that isn’t designed for high vibration. A proper vibration resistance design would encompass the entire device. (Plus, the footprints of RJ45 connectors aren’t standardized even among themselves.)Conductive glues?! Why would you want that?!?But as I said: brilliant solutions come from understanding the constraints. Having people suggest solutions, only for you toafterwardsreply with a constraint (which you knew about already!!) that ruled out that suggestion is just frustrating to them.

author: ftg
author_rank: Frequent Contributor
timestamp: October 21, 2024, 03:21:47 pm
content: Quote from: NCG on October 21, 2024, 09:22:13 amFor GbE M12 connectors you want X-coded 8-pins.One such example:https://www.turck.de/datasheet/_en/edb_100002337_gbr_en.pdfThe 100Mbit one's seem to be D-coded.