Author Topic: best way to tin very fine braid  (Read 637 times)

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Offline cncjerryTopic starter

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best way to tin very fine braid
« on: May 22, 2024, 08:00:52 pm »
I'm trying to repair some Bose wired earplugs with noise canceling.  they have 16 wires coming from the earpieces.  6 of them have very fine shielding wire that needs to be grounded.  I don't think scraping them is the right approach, maybe a solder pot?  what do you think?  I only need about 1/32nd of an inch tinned on the ends, of course.

Thanks
 

Offline BrokenYugo

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Re: best way to tin very fine braid
« Reply #1 on: May 22, 2024, 08:07:44 pm »
Dab of flux on wire end, put a small (so a ton doesn't wick up the braid) fresh blob of solder on a freshly tinned tip, introduce wire to blob until you see it wet the wire. Solder pot is overkill for occasional use.
 

Offline Overspeed

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Re: best way to tin very fine braid
« Reply #2 on: May 22, 2024, 08:20:23 pm »
Hello

Tin is easy , but the concern is the wire insulation best is to use krapton wire or PTFE wire available from some mil / aero company for few USD per meter

Other way '' cold process '' is to use liquid Tin coating for PCB , but you need to flash etch the wire ( Peroxyde + hydrocloric acid ) rince and dry with alcoll to remove all surface contamination

Regards
OS
 

Offline jpanhalt

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Re: best way to tin very fine braid
« Reply #3 on: May 22, 2024, 08:50:02 pm »
Are you sure they won't take solder as is?  Why not?  If it is a question of enameled wire, aka magnet wire, Broken Yugo is right.  It is "probably" solderable.  If it is not, then a molten salt (NaOH or KOH + NaNO3) bath is probably the solution, but I doubt very much that is needed.
 

Offline cncjerryTopic starter

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Re: best way to tin very fine braid
« Reply #4 on: May 23, 2024, 05:17:15 am »
I haven't tried to put solder on the braid.  I would be surprised if they take it as-is since there are 6 wires with braid around them bundled together.  The braids could be all at the same potential, I haven't tested that yet, but I believe they are insulated.

The cable runs from two earphones that have microphones in them for noise reduction.  There is also a few switches in the cable for advancing, pausing, etc., and again, another mic, if you want to listen to people yelling at you.

This is going to be a challenge since I have a really bad neurological tremor.  All the wires and braids were glued down with some kind of black tar that was tough to clean.  Luckily the connections are numbered so I snipped a piece of cable and taped it to a paper with the numbers as the colors are sort of the all the same.

I'll try just solder on an iron first, I guess.  This is some of the finest braid I've seen.

Jerry
 

Online tooki

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Re: best way to tin very fine braid
« Reply #5 on: May 24, 2024, 11:38:24 am »
I haven't tried to put solder on the braid.  I would be surprised if they take it as-is since there are 6 wires with braid around them bundled together. 
Solderable ≠ uninsulated. It’s really common for headphone wire to be solderable enameled wire, which is wire whose enamel burns away at (elevated) soldering temperatures without producing byproducts that impede soldering. You just follow the instructions BrokenYugo said, and turn up the soldering iron temperature if needed. (I normally solder at around 330C, but to burn off the solderable enamel requires 400C or higher.)
 

Offline mag_therm

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Re: best way to tin very fine braid
« Reply #6 on: May 24, 2024, 01:01:27 pm »
Hi Jerry, my story might give some Quietcomfort, but not much else.
I had the original Bose wired noise cancelling headphones from 1997.

After about 15 years and ~ million miles of travel, one of the fine braids broke off at a pcb pad.
I recall having a difficult time heating with iron, fluxing and scraping with scalpel until I suppose about 3/4 of wires were tinned and some were broken off by the scraping.
After about 2 more years, the cable broke inside the jacket at the entry to earcup , so I called it unrepairable.

For homebrew transformers magnet wire ( 18 to 30 g), I use a small oxidising oxy-acet flame, and quickly pass the end through. After scraping the soot off, the copper is very clean.
But this method would surely melt those fine braids.
 

Offline donlisms

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Re: best way to tin very fine braid
« Reply #7 on: May 24, 2024, 05:17:34 pm »
Something to keep in mind, here, is that the original maker needed a fast, simple, inexpensive way to make these connections. The more extreme the idea about how to repair them now, the more likely it is to be farther away from what's really required.
 

Online MathWizard

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Re: best way to tin very fine braid
« Reply #8 on: May 24, 2024, 09:33:47 pm »
 Some Litz wire type stuff has strands of thread in them too, even in USB cables I've seen thread inside the wire's plastic insulation, and with a chaukly substance, and others with something that was sticky.

I don't have any good memories of trying to solder headphone wires, ferrite rod antenna wires, or USB wires.
« Last Edit: May 24, 2024, 09:37:07 pm by MathWizard »
 


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