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Crimped butt connectors


Anderzander

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Yes you can get back-to-back uninsulated crimps; I use them quite a bit, along with "Bootlace ferrules" to crimp on to the end of multistrand cable before putting it into a screw terminal.

These ones:

http://www.wiringproducts.com/heat-shrink-butt-splices

come already fitted with the heat-shrink sleeve for faster assembly.

Properly crimped and sleeved joints [by which I mean those made with a ratchet crimper, not one of the stupid pliers-things you get in cheap crimp-connection kits] are far better than soldered joints. There's no place for soldered wire joints in cars (and indeed they are banned in aircraft wiring-harnesses).

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posted this before in previous solder v crimp debate

Why solder? . Manufacturers of millions of cars don't do it and very rarely do they fail.

A mechanical crimp joint does not need soldering, i've been building looms and modifying looms throughout my career and soldering in my view is to cover a poor crimp, if you want to add anything to a crimp joint then use top quality heatshrink

The soldering process itself can damage other components from heat.
There is a 'spark-gap' condition at large gauge soldered wire connections, where the heat generated by the solder's resistance could be enough to melt the insulation or set it on fire.
Wires tend to flex near soldered joints, increasing the chances of breakage and corrosion, particularly after heating. Heat causes wire embrittlement, strand fatigue and corrosion.

A soldered joint is inferior, where wires are 'stuck' together, while a crimped or welded joint is the equivalent effusing the metal. With a soldered joint, there is only minimal contact between the wires themselves, and the main electrical path is through the solder (which has more resistance than the copper of the wire). Though crimping effectively reduces the cross-section of a wire by about 20 percent, the small resistance added amounts to an essentially unimpeded electric flow across the crimped joint."

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Solder may be 'inferior', but I've not had a single one of my soldered joints fail. I'm not in any way saying is better (or worse in fact) than crimping, and no I am not talking about 'large scale' joints.

I do crimp many other times, and with the proper tools, but I see no issue running the two alongside each other. A solder join like above is strong, slim and protected with heatshrink, so meh, what can really go wrong?

Just saying...

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Thanks Tanuki

I've had a quick look using 'back-to-back' and ferrules as search terms and I'm finding a lot more stuff.

I have a ratchet crimped for spade terminals - so I'll look to identify the type for these and pick one up.

Any recommendations on type appreciated ? I saw one that looks like it presses in from four sides - and one that looks like it just pinched it from two, I'm not sure which is best or correct.

One of the things I'm hoping to do with it is also to splice two wires into one with them. There a few splices like that on the Td5 loom and I think it's the same type of crimp.

Yes you can get back-to-back uninsulated crimps; I use them quite a bit, along with "Bootlace ferrules" to crimp on to the end of multistrand cable before putting it into a screw terminal.

These ones:

http://www.wiringproducts.com/heat-shrink-butt-splices

come already fitted with the heat-shrink sleeve for faster assembly.

Properly crimped and sleeved joints [by which I mean those made with a ratchet crimper, not one of the stupid pliers-things you get in cheap crimp-connection kits] are far better than soldered joints. There's no place for soldered wire joints in cars (and indeed they are banned in aircraft wiring-harnesses).

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posted this before in previous solder v crimp debate

Why solder? . Manufacturers of millions of cars don't do it and very rarely do they fail.

A mechanical crimp joint does not need soldering, i've been building looms and modifying looms throughout my career and soldering in my view is to cover a poor crimp, if you want to add anything to a crimp joint then use top quality heatshrink

The soldering process itself can damage other components from heat.

There is a 'spark-gap' condition at large gauge soldered wire connections, where the heat generated by the solder's resistance could be enough to melt the insulation or set it on fire.

Wires tend to flex near soldered joints, increasing the chances of breakage and corrosion, particularly after heating. Heat causes wire embrittlement, strand fatigue and corrosion.

A soldered joint is inferior, where wires are 'stuck' together, while a crimped or welded joint is the equivalent effusing the metal. With a soldered joint, there is only minimal contact between the wires themselves, and the main electrical path is through the solder (which has more resistance than the copper of the wire). Though crimping effectively reduces the cross-section of a wire by about 20 percent, the small resistance added amounts to an essentially unimpeded electric flow across the crimped joint."

Sorry but most of that is complete rubbish.

Car manufacturers dont solder because its a) more expensive to perform and b) the looms are made with industrial quality crimp tools.

The DIY insulated crimps, even using a decent tool, dont match up to the contact resistance and reliability of a folded wing crimp.

Soldering is a very good solution for repair and modification work if done properly.

Of course above a certain size, in very high current applications such as battery cables, crimping becomes the prefered choice.

My issues with your post:

-If you are damaging components by soldering, you dont know how to do it.

-You misuse the term spark-gap, when you mean contact resistance. There is no reason a solder joint will have a higher resistance than a crimp, and in many cases it will be lower. Even a crimp has a copper-tin-(some air)-tin-copper interface and far less surface area contact than solder.

Yes copper has about 10x lower resistivity than Tin\lead solder, but since resistance depends on cross-sectional area, and that the joint will have a lap and bulb of solder around it the actual resistance of the joint will often be lower than the wire itself.

-All joints need strain relief. This is just as true in crimping. Whether soldered or crimped a tail of adhesive heatshrink solves this and seals to boot.

-Crimp joints under corrosive environment are worse than soldered, as water penetrates the air gaps in the crimp.

Its a different matter and some of the above does not apply if you have the tools to perform air-tight folded crimp joints as used professionally, but in our applications with DIY tools there is most definitely a place for solder joints.

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Supaimpy , I fully accept that its hard to cover all aspects of a topic in a few lines in a forum post but your comments are misleading.

The soldering process itself can damage other components from heat.

(only if you cannot solder)

There is a 'spark-gap' condition at large gauge soldered wire connections, where the heat generated by the solder's resistance could be enough to melt the insulation or set it on fire.

(only if you cannot solder)


Wires tend to flex near soldered joints, increasing the chances of breakage and corrosion, particularly after heating. Heat causes wire embrittlement, strand fatigue and corrosion.

(This is a sign that the joint was incorrectly made and no strain relief was made.)

A soldered joint is inferior, where wires are 'stuck' together, while a crimped or welded joint is the equivalent effusing the metal.

(this is a sign that the joint was incorrectly made, soldered joints are not "wires stuck together" )

With a soldered joint, there is only minimal contact between the wires themselves, and the main electrical path is through the solder (which has more resistance than the copper of the wire). Though crimping effectively reduces the cross-section of a wire by about 20 percent, the small resistance added amounts to an essentially unimpeded electric flow across the crimped joint."

(this shows a lack of knowledge or ability to articulate about the soldering process)

There are concerns about failures of soldered joints. For example an inexperienced technician with poor skills may make a bad joint due to poor conductor preparation and strain relief. In almost all of the failures I have analysed cable preparation, in particular cleanliness has been the cause of failure and not the type of joint deployed.

There is also a concern about atom migration in high current joints subjected to extreme temperature variations.

For many applications including construction, repair and modification there is still a place for soldered connections, in the right circumstances they will be better than a crimped connection.

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Thats ok , you have your view I'll go with the auto manufacturers, and the insurers .

The poor soldering technique or poor crimping take your pick, with a ratchet crimping tool its pretty hard to get it wrong anything that involves heat is easier to get wrong

I still say a more reliable joint is a crimped joint.

When I find the article I have from VAG, i'll post it up,it makes very interesting reading about the argument of solder v crimp and its not purely down to cost

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@ supaimpy - The point is this.

Crimping with high quality contacts and tooling produces a good joint. But crimping in our DIY area with insulated crimps and budget tooling is quite poor. You will be able to find many industry documents that have no relevance to our application.

Your sweeping statement that crimping is bad, without considering the details is entirely incorrect.

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It really is horses for courses and both techniques are fine, neither is bad.

Forty years of soldering and pretty much all of my professional life here has involved making reliable joints that range from bigger than a starter motor to to signal circuits that need to have intermodulation performance at -165dbc , this has included forensic examination of failures and I'd be willing to bet a big chunk of money that I can turn out a better job than a cheap crimp from China - many of the DIY ratchet tools are very inaccurate and the ends do not pass a pull test. Just buying a ratchet tool and a bag of crimps is no guarantee of quality. Equally in the hands of an un trained technician in a dirty garage with old corroded wire a hot iron and a roll of tin/lead can be a disaster.

What's important to recognise is making good electrical connections is nothing to do with the method and all to do with the implementation

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Can't resist sticking my £0.02 in.

For the homegamer, a £20 un-insulated crimp tool will produce far more reliable results than a £20 soldering iron. You can do a pull test and see the crimp, for one, unlike an insulated crimp. A bad solder joint takes experience to spot, whereas a bad (un-insulated) crimp is easy to see.

But do whatever you're comfortable with. Just don't, for the love of all that's holy, break the fourth rule of LR4x4.com club:

Don't use Scotchloks!! :rtfm:

Matt

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Anyone got an suggestions for the right crimp tool for the type of crimps I'm referring to please ?

There are entire web sites for this discussion ... erm so I'm told :-)

Pressmaster make a nice crimp tool that is very accurate but maybe too expensive for home use.

20 quid crimper .... no ta, not here. Same as scotchlocks

http://www.pressmaster.se/products/

I carry an MCT and a load of dies in my box but the entire range seem well made

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