Build up umbilical cable

I’d like to build up various umbilical cables. Two parts..

1. A wire wrap that tightly bundles the wires.
2. A tough but relatively flexible (plastic?) sheath, ideally also tight to the wrapped, bundled wires ..something like heat shrink, but thicker and tougher.

Thanks for suggestions.
 
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CarlyBoy:

I've made umbilical cables for several preamps and phono preamps, including two last year. The connectors are typically Chinese aviation grade Y2M connectors and plugs, which seem robust and are certainly inexpensive (e.g., Y2M series 21mm Y21M fast buckle Aviation cable connector plug male & female 2/3/4/5/7/10/14/16 pin 2p/3p/4p/5p/7p Army green|Connectors| - AliExpress). I use single PTFE-insulated 600V stranded wires which are very loosely wrapped in plumber's teflon tape and then inserted into braided copper sleeving (which is connected at one end to the ground wire) and then finally finished in braided TechFlex. They're easy to make, flexible, inexpensive and should stand the test of time.

Hope that helps.

Regards,
Scott
 

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CarlyBoy:

I've made umbilical cables for several preamps and phono preamps, including two last year. The connectors are typically Chinese aviation grade Y2M connectors and plugs, which seem robust and are certainly inexpensive (e.g., Y2M series 21mm Y21M fast buckle Aviation cable connector plug male & female 2/3/4/5/7/10/14/16 pin 2p/3p/4p/5p/7p Army green|Connectors| - AliExpress). I use single PTFE-insulated 600V stranded wires which are very loosely wrapped in plumber's teflon tape and then inserted into braided copper sleeving (which is connected at one end to the ground wire) and then finally finished in braided TechFlex. They're easy to make, flexible, inexpensive and should stand the test of time.

Hope that helps.

Regards,
Scott

Great ideas. Is the inner copper sleeve meant as a precautionary path to ground?
 
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CarlyBoy:

Yes, it's shielding. I don't know just how effective or necessary it is but the cost is insignificant and it doesn't adversely affect the flexibility of the cable, so why not?

Regards,
Scott
Scott, good info. I am looking for some sleeving for cabling, I tried some braided stuff but the ends unraveled after cutting, to the point that it wasn't really useable.
Looked at the techflex stuff you mentioned, does that stay intact after cutting?
Is there anything in the specs that gives a clue to whether it unravels easily?

Jan
 
Scott, good info. I am looking for some sleeving for cabling, I tried some braided stuff but the ends unraveled after cutting, to the point that it wasn't really useable.
Looked at the techflex stuff you mentioned, does that stay intact after cutting?
Is there anything in the specs that gives a clue to whether it unravels easily?

Jan
I use expanding nylon braid to make up a custom "snake" to link my guitar pedalboard to my amp and rack. I sleeved the ends with glue-lined heatshrink tubing to prevent it from fraying. Works a treat!

Cheers!

Ant.
 
I used multi-conductor cable.
In-wall speaker wire is 4x16ga and flexible.
I also have used 18/5 thermostat cable. Solid wire so not as flexible.
Then there's a making a loom... That case I use that plastic wire loom crap you find in cars (split loom).
They also have an aluminized version: https://www.cabletiesandmore.ca/convoshield-aluminized-tubing
1655297817850.png

Also depending on the length and size of wire, you could use a shower hose.
1655298144444.png
 
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I use expanding nylon braid to make up a custom "snake" to link my guitar pedalboard to my amp and rack. I sleeved the ends with glue-lined heatshrink tubing to prevent it from fraying. Works a treat!

Cheers!

Ant.
That's a good tip, I tried with scotch tape and that didn't work well.
Glue-lined heatshrink tube sounds good, I also need that over each pin to keep the specified HV spec from Lemo/Redel.

jan
 
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Jan:

I use regular scissors to cut Techflex and have to be careful not to allow it to unravel too much. Yes, if you allow it to unravel it can quickly become a mess, but with a little practice it isn't hard to maintain a reasonably decent end and it doesn't matter if there is a little fraying. The trick is to move the Techflex's cut end into its final position as neatly as possible so that the fraying overshoots where you want the end of the Techflex to be, and then secure the Techflex in place with a short length (perhaps 1 cm) of shrink-wrap. Done properly, there should be no fraying at the point where the Techflex slides under the heat-shrink. Then snip off the stray strands of Techflex that exit at the end of that piece of heat-shrink (a point which should eventually be hidden by the connector). I then position a second, slightly longer piece of shrink-wrap over the first piece. Together, the the two pieces of heat-shrink hold the Techflex in place.

Reading what I just wrote, it sounds more complicated than it really is. The process is really simple and the cost of practicing the art of beautiful umbilical construction is rather low. You're an inventive, bright guy and you'll undoubtedly get the hang of it straight away.

One other thought: at the risk of demonstrating my truly indecent OCD, you can get some really attractive results by overlaying two different sized and colored Techflex runs on an umbilical cable. Use the "correct" size for the first run (in whatever color you fancy) and then add a second layer of Techflex over it in a contrasting color using a size that is 1/2 or 1/4 the size of the first run. To fit over the existing cable, the second run of Techflex has to expand so much that the space between its strands opens up, allowing the underlying color to show through. It's a really nice effect, even if you're the only one who ever sees it. I recently built a pair of interconnects for my parents using "undersized" Techflex which demonstrates the effect (photo below).

Well, by any reasonable measure I've embarrassed myself enough on this topic. Enough said.

Regards,
Scott
 

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Hi Jan,

For what it's worth: It does not need to be glue-lined. This is a two-cable version I made a while ago. I guess a cable tie would work too, but the heat-shrink is neater.

Another tip: Use bigger than expected nylon braid, and keep it fairly wide/loose on the cables so that they still flex.

Cheers,


Ant.



snake.jpg
 
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I really don't want to do that, I want it to stay flexible.

@Scott - OCD or not, that's a very good looking cable! But your description is a great help, I'll show my first cable as soon as I have time to do it in a single run. Maybe tomorrow.

@ANT - good tip too. This is for a 3kV cable and REDEL (the LEMO brand that makes my 5-pin connectors) says to use glue lined shrink tube over the pins to maintain HV isolation and creepage.

Jan
 

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Jan:

My umbilicals include a tinned copper braid, so my process is to first select the smallest tinned copper through which I can run the wires. I very loosely wrap the wires in plumber's teflon tape before inserting the wires into the copper braid (it's a habit and may not actually be necessary). I use the same size of Techflex as the copper braid. If you want to add a second layer of Techflex for cosmetics, I'd start with a Techflex diameter that is about one-half the diameter of the copper braid (e.g., 1/4" diameter Techflex for the second layer over 3/8" or 1/2" copper braid and Techflex layers).

In the case of your example, the copper braid and first Techflex layer should both be 1/4" (or 3/8" if the wires are too tight in a 1/4" sleeve). If you wanted to try a second cosmetic layer, use 1/8".

I'll say this for my umbilicals: they are flexible!

Good luck with your project! And please post photos and a follow-up if you pursue this!

Regards,
Scott