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soldered junctions
dnmalc - 11/8/10 at 08:34 PM

In modifying the loom I am having to remake a number of points where multiple leads are joined together with solder. I am not happy that I have a means of making as good a solder joint as ford originally did due to the thermal mass. Hence I am looking for some other means such as a bus bar as i am not happy using a multiway bullet connector.

What have others used for this purpose?

YQUSTA - 11/8/10 at 08:53 PM

This maybe of use just need to add crimps to the cables.

LI NKY

paulf - 11/8/10 at 09:00 PM

If you do not have a large soldering iron then
you may be able to use a blowtorch with a fine nozzle such as the small refillable ones sold by Maplins etc.
Paul

wilkingj - 11/8/10 at 09:25 PM

40 years ago i spent an entire week stripping wires, wrapping them around tags and then soldering them. Only to have the instructor come and tear me apart!

Solder is not a good electrical conductor and made of lead and tin, whereas cables / wire is made of copper.

I was trained to accept that the Mechanical joint is what carries the current, (wrapped around the tag, or these days crimped) and the soder just held the mechanical joint in place.

As for soldering with a blowlamp, its going to end up burning your insulation back, as the flame is not focused enough, ie as when using a soldeing iron as the heat source. Also the bare flame will oxidise the surface, and you may need corrosive flux to get a good joint. Corrosive flus isnt a good idea on wiring, as its bloody diffcult to wash off sucessfully.
Having said that, it can be done. I would practice on some scrap wire before attacking your loom!
I have had 40 years using a soldering iron, and other utensils, I hate using a blowlamp, unless you are plumbing a lead pipe! Its too indiscriminate.


There is nothing wrong with crimped joints. HOWEVER.....
They need to be crimped to the correct pressure for the wire size and use the correct connector and crimpers.

These cheapo £2 plier types are crap and will bring rise to faults in later years.
Spend £15 and get a decent set of ratchet crimps that will crimp to the correct pressure, and you will have a good connection for a very long time.

For this situation, a bus bar would be OK, but make sure its properly insulated from ground if its a power bar, or well earthed if its an earth bar.
I would also use a small star shakeproof washer under the screw heads in cse of vibration... well its a car and they vibrate!

Or....

Go to Maplins (£7.99), as Half-Fords (£12.99), and everywhere else is dearer and get one of these.

(This is the Wilco web page, but its got a picture, and I cant find it in on Maplins site, but I got mine from there)
LINKY

or the smaller version which I dont know the part number.
Hope this is of use to you.

MakeEverything - 11/8/10 at 09:49 PM

"Solder is not a good electrical conductor and made of lead and tin, whereas cables / wire is made of copper.

I was trained to accept that the Mechanical joint is what carries the current, (wrapped around the tag, or these days crimped) and the soder just held the mechanical joint in place. "

40 years ago, this may have been the case. 13 years ago when i obtained my distinction in level 3 electronics, it wasnt.

Modern solder no longer contains lead, and is very much a conductor.
The term "Tinning" is still used, however, the old 'tin' products in solders has been replaced with modern, non hazardous conductive material.

I agree with Wilkingj with regards to the crimping tools. Ratchet is the only way to crimp, and anything else should be thrown away.

Beware using solder when you dont need to. Soldering makes the joint brittle if subjected to vibration, which will cause you problems in the future.

Hope this helps.

[Edited on 11-8-10 by MakeEverything]

MikeR - 11/8/10 at 09:59 PM

What about the wilco wiring block thats push in or the cheapo equiv who's name i forget despite buying a hundred for 9 quid today.

RazMan - 11/8/10 at 10:51 PM

Solder joints are (or were) considered a bad idea by most automotive manufacturers and I seem to recall that it was mainly because of their brittle nature. In a loom application there is always a certain amount of vibration or movement which, over time, will find any brittle joints and ...... well, you can guess the rest.

Having said all that, I soldered most of my joints in the places where the loom is firmly fixed to the chassis and in places where I would never be able to access after the car was finished. As a Telecom (GPO) engineer I was taught that the humble crimp was the best way to join a pair or wires, as long as they were insulated from the air with vaseline jelly - that strategy still exists today and there are gazillions of telecom cables (which require perfect continuity these days) in all sorts of environments and are, on the whole, extremely reliable.

If I solder a joint nowadays I use an aqueous based flux which is washed off before popping on a heatshrink sleeve for protection. Crimped joints are normally used at the equipment end and a proper ratchet tool must be used to ensure the correct pressure and position is applied.

deezee - 12/8/10 at 08:04 AM

quote:
Originally posted by wilkingj
Solder is not a good electrical conductor and made of lead and tin, whereas cables / wire is made of copper.


If its a good enough conductor to put together my Megajolt I'm confident its suitable for wiring up an indicator.

02GF74 - 12/8/10 at 09:55 AM

quote:
Originally posted by wilkingj

Solder is not a good electrical conductor and made of lead and tin, whereas cables / wire is made of copper.



hmmm, not sure that is strictly accurate. All metals are good conductors of electricity since that is how metals are defined.

A more accurate statement would be that lead/tin solder is not as good a conductor as copper - not been able to find any data for the 60/40 Pb/Sn solder but silver, copper, gold are the best conductors, in that order, so the solder has to be less good.

If solder was not good conductor, then no TV, CD player, radio, amplifier, computer, meagjolt, xbox would work since the electrical connection is made using solder, be it for surface mount or through-board wire components.

In the latter case, the mechanical joint is made by having the hole in the pcb the same size as the wire so that the component is supported.

Anyways, the way I was taught was that solder is for making the electircal circuit not for mechanically supporting the components.

In the case of joining two wires, the best way, if using solder, is to push the ends together interleaving the individual strands, twist and the solder.

I have used a single strand tied round the bare wires to stop them unravelling prior to the soldering.

As for junction boxes, a piece of copper pipe, cut, unfolded then flattened is a cheap but effective alternative - you can make 4.7 mm wide tags onto which your crimp on connector will fit.

[Edited on 12/8/10 by 02GF74]