Panel mount 4mm banana jacks and conductive spray-on paint recommendations ? - Page 1
Forum section: electronics / general

author: DC1MC
author_rank: Super Contributor
timestamp: October 21, 2018, 09:16:00 am
content: Hello dear volt nuts, I have a problem and maybe ( actually for sure) you can help me.For my little instruments I want to build a number of little calibration resistor boxes, that is my meter have binding posts placed similarly and I want to just plug the resistance box in, without extra wires and stuff.But for the life of me I don't know what to search to get the beautiful ones that I once see here on a similar box (and I've lost that post as well).So could you kindly recommend me some nice panel mount banana jacks with soldering ends and for panels of 1-3 mm thick ?Also, my Datrons calibration manual recommends that the resistor box should be shielded, is there a commonly used conductive spray-on conductive paint (with focus on EU/DE availability, my behind still hurts from the latest US buy and German customs / FedEx gang rape), I don't have too many way to drill in metal cases so I will use some available plastic cases.I've found this one:https://www.solianiemc.com/en/p/electrically-conductive-spray-paint-400-ml/but have no idea how good it is, I only know that will be not cheap.Many thanks for all the suggestions and ideas,DC1MC

author: branadic
author_rank: Super Contributor
timestamp: October 21, 2018, 09:50:30 am
content: What you can use isMulti Contact 22.1053mounted to a ptfe plate for isolation. There are other types too:https://de.rs-online.com/web/p/4-mm-laborsteckverbinder/2615531/https://de.rs-online.com/web/p/4-mm-laborsteckverbinder/2622028/https://www.newark.com/multi-contact/22-1053/banana-plug-50a-screw/dp/82K9592I would not recommend using a plastic case with some paint. Metal is the way to go in any case. Aluminium has the advantage of high thermal capacity, giving good thermal stability. Aluminium on the other hand is not a good way for magnetic shielding. You can use rf metal sheet (Weissblech) cases.You will need some capabilities to drill and make threads.-branadic-

author: capt bullshot
author_rank: Super Contributor
timestamp: October 21, 2018, 09:57:30 am
content: You can build shielded boxes from copper clad epoxy (raw PCB material). Some really nasty example here:https://www.amplifier.cd/set/start.html

author: DC1MC
author_rank: Super Contributor
timestamp: October 21, 2018, 10:11:13 am
content: @branadic: Thanks A LOT, I was searching desperately on Bananensteckverbinder but they never appeared, bookmarked and data-sheet saved, actually even not very expensive. Now while I lack processing PTFE capabilities (and actually a cheap source of PTFE plates as well) I've seen some kind of two pieces trough-hole isolator, one just has to drill a 6mm hole and screw the parts on and inside can put the banana jack and screw it on the isolator, if you knew where to get this one as well (or a place where they can be fabricated in DE-9, you'll be my double hero.@capt bullshot: Well, instead ofboxifyinga copper clad raw PCB, I prefer tocopperizean alreadyboxifiedplasic box (hey, I've invented two nice Silycon Valley startup names), and if I can get that tough hole isolators tha was talking aboe, I'll even consider a metal box.Cheers,DC1MC

author: DC1MC
author_rank: Super Contributor
timestamp: October 21, 2018, 10:35:25 am
content: Just for future reference, here are some other variants to consider:https://www.buerklin.com/de/einbaustecker/p/12f170with M4 tail and 18mm tail length.https://www.buerklin.com/de/steckerstift/p/12f152with M5 and 6mm + soldering lugNow where to find a nice 60x50 x25 metal box?Cheers,DC1MC

author: branadic
author_rank: Super Contributor
timestamp: October 21, 2018, 11:01:20 am
content: Added some more possible connectors to my post above.If the 60mm are not fixed, I like the Hammond 1455C801 cases.-branadic-

author: TERRA Operative
author_rank: Super Contributor
timestamp: October 21, 2018, 11:48:13 am
content: Quote from: capt bullshot on October 21, 2018, 09:57:30 amWow, that thing is a work of art.

author: MiDi
author_rank: Frequent Contributor
timestamp: October 21, 2018, 09:12:59 pm
content: For shielding you could use alu-/coppertape or thin copperplate - cut and glue inside box.But when you solder directly to the bananas, this should not be that critical.

author: DC1MC
author_rank: Super Contributor
timestamp: October 22, 2018, 05:57:35 am
content: About the box, I've chosen the Hammond 1550P, the WP has even a ferocious IP67 gasket but I think it's a bit too much.https://www.buerklin.com/de/aluminium-gehaeuse/p/60h3031Should I fill it with some oil in the end, or leave it in the air, and if oil, or other compound, what type ?Also, I'm really juat missing this PTFE isolators and it's there.Cheers,DC1MC

author: MiDi
author_rank: Frequent Contributor
timestamp: October 22, 2018, 10:27:42 am
content: If you want precision and stable resistors, you can buy them oil filled, e.g.vishay vhpseries.

author: DC1MC
author_rank: Super Contributor
timestamp: October 22, 2018, 10:57:22 am
content: Quote from: MiDi on October 22, 2018, 10:27:42 amThanks for the link, unfortunately I only have one kidney left, so until it grows back I can't sell the other one.Now that I'm doing to do some poor man calibration boxes (with just CAR5 and CAR7 resistors) I could fill them up with something to reduce the temperature and humidity impact, every bit helps.But the current big issue it the pass-trough PTFE isolator for the banana jacks, I could easily find on fleabay reasonably priced PTFE bars, but I have no idea where can I find someone with a small lathe in Mannheim and around who can build them and I wasn't able to find any premade ones.Any takers in Germany, I'll try to make your time worth spending.Cheers,DC1MC

author: MiDi
author_rank: Frequent Contributor
timestamp: October 22, 2018, 11:33:41 am
content: Think you do not want to go the effort for sealing the case for oil...You cannot avoid TC with oil filling, for humidity you can put some dessicant aka selica gel pack into it.Selfheating with your construction and only used for calibration purpose should not be the major issue