Cable splicing...the right way?

[komatias]

Hi All,

I hava a naggin feeling that there is a correct or good practice way to splice cables for example to add the intercom of the alarm to the original wiring loom. I despise the plasctic crimp splices as they seem to me like a botch job and not very permenant. What I am after is a good method of soldering a cable into the middle of another cable with minimum effort and damage to the insulation.

While we are on the case are there any tips for reducing the cold-solder effect outdoors? I dont have a garage so there is always wind to cool the solder as soon as it touches the cables.

Any tips photos suggestions are welcome. This is something alot of us will be interested in i think

 

[cookie]

I despise the plasctic crimp splices as they seem to me like a botch job and not very permenant.

you are so right.

what you want is quite tricky however, and i used to do MOD prototyping for many years.

if you are careful you can remove a piece of insulation from the middle of a wire run, tin it (thoroughly coat with solder) and the wire you want to join it, then do a lay on joint by putting them together with a freshly tinned soldering iron.

loads of practice, first class strippers, a proper pro soldering iron and it's still a bit tricky to get it perfect every time, especially if job is on the bike.

of course you then have to insulate it. heat shrink if you can get one end free to feed it down, often you can't. but don't use insulating tape, it marks the whole job down as a bodge straight off.

i don't bother these days. i usually achieve a good result with crimps & sometimes an additional Y piece. of course for this you need a supply of crimps & a PROPER crimp tool.

swings and roundabouts

just don't use those fecking horrible blue IDC connector things

 

[Noel]

The way I splice cables is to cut the cable you wish to splice into remove the insulation from both ends slide a piece of heat shrink tubing over one end (slide it along the wire so it's not effected by the soldering heat), prepare the wire your going to join in, then solder the three pieces together then slide the shrink tubing over the joint and shrink job done. As for soldering use a largest tip possible for the soldering iron that way the heat will not get soaked out of the soldering iron tip, use good qulaity flux cored solder.

 

[Doug]

The only thing I'd like to add is if you have the room, stagger the joins especially if your using through crimpps

 

[cookie]

Tthen solder the three pieces together then slide the shrink tubing over the joint and shrink job done.

i wish i could do that.

do you twist the wires? was an MOD no no. old habits die hard.

 

[Jimb]

Komitas

To do a prpoer soldered splice, strip a short section of the insulation ( 10mm ) away WITHOUT cutting the cable then tin the bare wire and wrap the wire to be fixed around the tinned section then solder up.
THEN to insulate use self amagamating tape available from Farnells or RS, this is not sticky except to istelf and sets to produce a premenant waterproof joint, insulating tape will not stick well enough but Self Amalgmating will.

The result is you have not degraded the integrity of the original wire by cutting it and the joint is permenant and solid.

 

[komatias]

Good stuff guys keep them coming...

I have tried self amalgamating tape and I must say I am not impressed due to its lack of heat resistance. If you wrap a cable near the engine heads it shrivels up realy badly and then flakes off. I haven't tried the paint on stuff yet though. Most difficult thing to find is the tape BMW uses to wrap the loom. That textile stuff I mean.

The problem with heat shrinks apart from getting them on in the first place is thier tendancy to shrink just by the heat that is conveyd through the cable itself.


Anybody else have to add to this thread?

 

[cookie]

vehicle wiring products do adhesive textile tape but not non adhesive

RS componants maybe?

 

[Greg Masters]

I've heard that BTBR favours Scotchloks.



Greg

 

[Greg Masters]

More seriously, I use the method that Jimb describes and BTBR suggested a good source of self-amalgam tape.



Greg

 

[Greg Masters]

While we are on the case are there any tips for reducing the cold-solder effect outdoors? I dont have a garage so there is always wind to cool the solder as soon as it touches the cables.

I now have a range of soldering irons from 15w to 40w. They're cheap enough to buy these days. I always try to remember that whilst you need the right temperature, you need the minimum of heat.

Greg

 

[Doug]

i wish i could do that.

do you twist the wires? was an MOD no no. old habits die hard.

I worked on copper cables at Pirelli for seven years and if a cable came up short we would have to join the pairs together (sometimes a 100pr .4mm or .5mm cable)

We would have to use a cold welder and take a 12hr shift to do it

But unofficially we would twist them, no solder either

 

[Noel]

i wish i could do that.

do you twist the wires? was an MOD no no. old habits die hard.

No, I usually solder the two side by side, then add the third one to them if it's in an awkward place I use a pair of crocodile clips on a short bar this also helps disipate the heat.

 

[(RIP) Kaister]

as an ex-racal military wiring apprentice this is how i would do it.

as - others have said strip a 10mm gap of insulation
Tin it in its natural twist - don't melt the insulation.
Get the end of the other wire - don't twist it and wrap it around the bare section spirally.

Solder the joint as normal.

Heatshrink would be no.1 choice - Self amalgam tape second.

 

[shugie]

as an ex-racal military wiring apprentice this is how i would do it.

as - others have said strip a 10mm gap of insulation
Tin it in its natural twist - don't melt the insulation.
Get the end of the other wire - don't twist it and wrap it around the bare section spirally.

Solder the joint as normal.

Heatshrink would be no.1 choice - Self amalgam tape second.

For small wires amalg tape is not so good, you can get Y shaped self-adhesive from RS if you want a pukka job. I favour twisting stranded only, spiral for solid core stuff.

I was taught that a sound mechanical joint should be formed first, then soldered to provide good conductivity. Solder is not strong.

Decent quality crimps are good, especially for larger cable sizes, but use a proper crimp tool, not a pair of mole grips.