Alternatives to those pre insulated butt joints

Dave Plowman (News) explained :

Whilst I accept that you cannot solder to corroded parts, nor can you make an acceptable low resistance crimp joint either.

Nope! Repair kits for damaged connectors supplied by manufacturers come with short fly leads ready for connection to the original loom. The fly lead is crimped to the connector; it is joined to the existing loom by soldering.

It often happens that one connector becomes faulty. The most common is probably the connection to the heater fan speed resistor pack. These often burn out, usually as a result of failure to replace the pollen filter, and destroy the loom connector. A repair kit is then used.

Why would a whole loom section need to be replaced if just one connector is faulty?

Because it is so common to replace electrical parts on cars now, all motor vehicle technician training includes basic electrical skills - at least VAG and Ford does.

I can assure you 100% that the most common way for an AA patrol to repair a damaged electrical connection is soldering. I'm typing this with a patrol looking over my shoulder, and laughing...

You *can*. Main dealers, and the AA, generally *don't*!

When a connector has been damaged, it is usually the case that overheating has occurred. This will usually be caused by a high resistance at the interface between a pin and its socket. The overheated connection damages the loom locally. That is why the repair kit that I have described is a much better method than just replacing the connector.

Dave, you are missing the point here I think!

I'm not suggesting for a minute that a repair would be carried out by soldering directly to a pin that was designed to be crimped.

My points above should clarify how these repairs are commonly carried out.

Where did I say that? I'm merely telling you what happens at the roadside with the AA, and at many main dealers. I've not expressed an opinion in this thread, except to say that either crimping or soldering would be OK for the OP if done properly.

Like everything else, pre-insulated crimps are perfectly satisfactory if used properly. I've used literally tens of thousands of them as a professional!

Chris

Links on the page lead to - pre-insulated terminals!!!

Chris

Have you not pondered why you'll not find cable/solder joints on near any connector you come across? Inside your computer, for example, where soldering is the norm for component to PCB etc all the interconnects have crimp or IPC from wire to connector. If soldering was better, why? It can't be simply for ease of construction. Same with car wiring - all the connectors are crimped - not soldered. Many years ago Lucas experimented with welding 1/4" connectors to their looms. But I've never seen an OE soldered one.

Yes - but not connectors. The only soldered connections within a car loom that I've seen are where several earths are grouped into one etc and protected from any flexing by the position within the loom - they are inaccessible and bound within it. Never on a multi-pin connector that may only ever be unplugged etc at build time. Those are always crimped.

Not really. These things are installed aftermarket by monkeys. Who would use sellotape and Scotchblocks if it saved money. And the other reason is a soldered connection can't be unplugged. Nothing to do with the quality of the connection itself.

You can't re-use a crimp.

Care to explain why?

Chris

A much larger area of contact.

Why would you use such things on a car when better terminals are available which match the originals in both construction and appearance? I'm obviously talking about older vehicles using 1/4" spade connectors etc where there are equivalents in pre-insulated.

I'd suggest you do a pre-insulated crimp using the minimum size cable the terminal is said to work with then strip off the insulation and examine the crimp. It will look poor. And can usually be pulled off the cable. Not so with a properly made crimp even without the strain relief.

It happens that Dave Plowman (News) formulated :

Crimped connections onto wire/cable are much cheaper and more reliable to do in automated manufacture. Flow soldering is cheaper and more reliable in automated manufacture of PCB's.

Here we are discussing manual methods of repair/modification with a choice crimp or soldering.

Then your browser can't cope with wrapped URLs. Try it again - I've put it in brackets which sorts out *some* browsers. Otherwise cut and paste the entire URL.

They sell all sorts - including pre-insulated types with heat seal. But they also sell the correct type for car use. Including pins for multi-plugs, etc. Of course I'm not saying they sell every possible variety.

Right. And this doesn't strike you as strange? The makers use crimped connections to the plug but specify soldered at a joint? To me it says they simply don't trust their dealers to crimp correctly. I wouldn't trust them to solder correctly either.

BTW - I assume you know that you should never tin a multi-strand wire before inserting it in either a crimp or an ordinary screw tightened terminal? The solder is reputed over time to creep out of the joint under the pressure, leaving a loose poorly made joint.

For a pro who has the correct tools crimping is faster and cheaper than soldering. As well as better. For an amateur making a few connections and who already has a suitable soldering iron and knows how solder properly - not guaranteed - I'll concede it may be the way to go. But we were in the main talking about pros.

Indeed - you'll hardly ever find solder used with flex. There are of course exceptions - things like microphone connectors, XLR types - are soldered but have the strain relief some way from the actual joint and gripping the entire cable. Terminals which fit single insulated wire are invariably crimped - look at the interconnect wires inside a split load CU at home where they are carrying high current at mains voltage. Never soldered. And the makers obviously have that choice without any real cost penalty.

I don't need to...

I've probably looked inside more crimped connections in order to check that they had been made properly than the total number of connections of all types that you have ever made in your life.

As I said elsewhere in this thread, I worked in the electrical industry. I have used huge numbers of methods of connection including crimped and soldered joints in cable sizes ranging from 0.32mm2 to 300mm2.

I spent a large amount of that time designing and building bespoke control panels for my employer. Part of my job was, in consultation with others, to specify a standard for external contractors to use when supplying equipment that needed a control panel, and to check compliance with that standard. We specified pre-insulated A-MP crimps (now sold by Tyco) for everything that needed a lug or in-line connection, and insulated bootlace ferrules for everything else. Those of us who did this had a combined experience in the electrical field of perhaps 60 or more years. We never had cause to doubt our decisions...

I can guarantee that you will not pull off a properly made crimp of any type that has been applied to A-MP standards. The cable will break first!

Chris

Your reply suggests not. A properly crimped terminal is shaped round the conductor. I've got many crimp tools for various uses and they generally all work the same - they have heart shaped jaws which are designed to pinch the originally round terminal back on itself pulling in the sides etc. A pre-insulated type simply flattens the lot.

BTW - you have no idea how many I've made or examined.

Which cables use soldered on terminals these days?

So you're simply backing up what I said - you use proper crimps for the job. I sincerely hope you've never specified these universal pre-insulated types. The only equipment I've them used on was poorly made US stuff where I'd guess they were converted for UK use on a small scale.

You seem to be deliberately moving the goalposts. *I'm* the one saying that a properly made crimp is the ideal. But that I've seen plenty of pre-insulated types that simply pull off the cable despite being apparently made with the correct crimping tool. And that if you examine the business part by removing the insulation you'll see why - they are not properly crimped when the smallest cable they say can be used is. If the cable is the maximum size the results are better.

Dave, this reply suggests that you do not know how a properly crimped connection is formed. Google for "cold-welded crimp".

No, I don't. You did say earlier that your use of them was confined to an amateur basis however. Mine is most definitely not.

Where did I mention soldered *terminals"?

The OP was asking a question that could be answered by suggesting soldered

I did indeed specify pre-insulated crimps; I just said so in the paragraph above you are replying to!

Crimped joints and lugs were invented and patented by an American company; Aircraft and Marine Products. (A-MP.)

Their products, including the pre-insulated ones, carry MIL certification amongst other things, so I'm sure they will be entirely capable of satisfactorily joining the OP's car radio connector!

I have never questioned the suitability of crimped connections for use in the automobile industry; in fact I've championed it on usenet. I merely pointed out that for some reason, they are seen as unsuitable in the motor trade. This is what I said earlier in my reply to the OP:

"For some reason, the motor trade favour soldered joints insulated with heat shrink sleeving.

This is out of step with the rest of the electrical world, where soldered joints are considered at best a bodge, at worst a breaker of regulations.

Whichever method you use, if done properly it will be reliable."

I have never, ever seen a pre-insulated crimp joint that I have crimped, or any done by an electrical tradesman, fail where the wire can be pulled out.

That's not to say that I haven't seen it happen where amateurs have attempted such a joint without the correct skills or tooling. That doesn't make the crimp joints faulty...

Chris