Crimp *and* solder a crimp connector? Good? Bad? Why?

[wraper]

Well but crimping with spring loaded tool like the expensive over 100Eur KNIPEX
does not make gas tight ferrule crimps.

Where this assumption comes from?

Nobody measures wires and crimped result with micrometers against a standard like they should, yet everyone pretends crimp is better then soldered, or crimped then soldered is even worse. Where is only logical that to insert the connector pin into the block you must crimp it first and then solder, not the other way around.

Solder penetrates into the wire and makes it fragile. If vibration is present, wire may just break near to connector. Flux, which penetrates between the strands as well, may cause corrosion, especially in high humidity conditions.

[nctnico]

It can be used in screw terminal. This is exactly what was done in all electrical outlets in lamps in Europe and in Russia in 80's-90's and it worked OK. AFAIK there were no ferrules back then.

NOOO! Never ever use tinned strands in a srew terminal. The solder will be pushed out and the connection will become bad.
Besides that the solder joint will get bad after 20 to 30 years. You can pull it apart very easely. Crimping OTOH is a cold welding process which doesn't degrade so quickly over time.

[smile]

Crimp made in the end of the video looks like crap.

The KNIPEX crimp also looks like crap in their own demo video, how do you explain this?

[Mr. Scram]

Look at it this way, the wire connections in a spacecraft (which is probably the highest vibration environment you will find) are crimped and not soldered. Crimping works if you use the right tools and is ultra reliable, soldering will decrease this reliability.

It's high vibration, but only for a short while. An aerospace engineer once told me they basically design everything to withstand the first 90 seconds of vibrations or so from a mechanical point of view. After that, everything is smooth sailing. Obviously, that's going to impact the kinds of failures you are and aren't going to see.

[smile]

@wraper
"Where this assumption comes from?"

From the fact that the tool is spring loaded, you can even adjust the crimp force by turning the adjuster.
Only Hydraulic crimpers that have few tons of force will make air tight crimps, and ferules they use are way different, they are very thick.

[wraper]

The KNIPEX crimp also looks like crap in their own demo video, how do you explain this?

Connector was too small small for the wire used. Video is not clear enough to see how strands were crimped, but it's obvious this connector cannot fully enclose insulation of this wire regardless of the tool used.

[smile]

Look at it this way, the wire connections in a spacecraft (which is probably the highest vibration environment you will find) are crimped and not soldered. Crimping works if you use the right tools and is ultra reliable, soldering will decrease this reliability.

It's high vibration, but only for a short while. An aerospace engineer once told me they basically design everything to withstand the first 90 seconds of vibrations or so from a mechanical point of view. After that, everything is smooth sailing. Obviously, that's going to impact the kinds of failures you are and aren't going to see.

Well obviously said that if you solder a crimped connection you should make a shrink tube type stress relief on every wire.

[wraper]

Look at it this way, the wire connections in a spacecraft (which is probably the highest vibration environment you will find) are crimped and not soldered. Crimping works if you use the right tools and is ultra reliable, soldering will decrease this reliability.

It's high vibration, but only for a short while. An aerospace engineer once told me they basically design everything to withstand the first 90 seconds of vibrations or so from a mechanical point of view. After that, everything is smooth sailing. Obviously, that's going to impact the kinds of failures you are and aren't going to see.

Well obviously said that if you solder a crimped connection you should make a shrink tube type stress relief on every wire.

And from my experience I can say that heatshrink somewhat mitigates the issue but it still remains.

[Mr. Scram]

Well obviously said that if you solder a crimped connection you should make a shrink tube type stress relief on every wire.

I'm not sure what you're trying to say, but neither he, nor I, did state anything of that nature.

[smile]

I can say that Engineer PA-09/PA-21 or PAD series crimps better than KNIPEX own video.
http://tech.mattmillman.com/info/crimpconnectors/

But you must agree that Engineer crimps are not airtight. As such if Japan crimp tool can't replace OEM and the OEM costs 300-500Eur for single piece of die, then crimping its crazy nonsense if you are not a factory.

[wraper]

@wraper
"Where this assumption comes from?"

From the fact that the tool is spring loaded, you can even adjust the crimp force by turning the adjuster.
Only Hydraulic crimpers that have few tons of force will make air tight crimps, and ferules they use are way different, they are very thick.

Few tons you say? Tons do not mean anything without knowing area they are applied to. Such crimpers are used for very large crimp connectors, pressure applied to the unit of area might be even smaller than in ratcheting hand crimper. If you will apply tons of pressure onto small connector, metal will just squeeze out from both ends.

[wraper]

I can say that Engineer PA-09/PA-21 or PAD series crimps better than KNIPEX own video.
http://tech.mattmillman.com/info/crimpconnectors/

But you must agree that Engineer crimps are not airtight. As such if Japan crimp tool can't replace OEM and the OEM costs 300-500Eur for single piece of die, then crimping its crazy nonsense if you are not a factory.

I own PA-09 and can say it's a piece of crap. Very unreliable tool. I even filed it a bit, so it could close tighter. Crimps it made were very loose and wire often could be pulled out of connector easily, with applying minimum force.

[smile]

my hats off to anybody showing a ratcheting KNIPEX crimper cut cross section like in photo you show for typical connectors. I'm very interested in this tool

because it's somewhat universal and that makes it cheaper. Just remember for photo to be like in the image above you AFAIK should waterjet cut it. Cutting with hacksaw will make false sense of wires welded together.

[vk6zgo]

Just adding my 2 cents worth.

Over many years, I have seen plenty of crimped connections breaking off just behind the crimped part.
These were supposedly "properly crimped with the correct tool", as they were factory jobs.

Automotive ones seem to be the worst, as they don't seem to provide enough support for the wire.
It seems that the clamp which is supposed to crimp around the insulated part of the wire during the process doesn't close tightly enough.

The repair has been to solder the connector, with  in every case, a longer resultant life time than the original.

I have also seen crimp connector failure in Broadcast Transmitters & other such equipment.
Again, in many cases, the answer has been replacement with a soldered lug, due to not having the correct tool or lugs, & needing the equipment restored to service ASAP.
 
Even with the correct tool & crimp connectors, it is sometimes difficult to find enough length of cable to re crimp, as the conductors & insulation have often been "cooked" due to the fault.

Trying to crimp stranded cables which have been  over heated is a recipe for disaster, so in some cases, it is necessary to splice a new section of wire in place.
At this point, if it is at all viable, it is best to make up a new cable entirely, with properly crimping & stress  relief at both ends.

A good crimp connection is very good indeed, but a bad one is an invitation to trouble.
The  thing is, if manufacturers can't get it right, what chance has someone with an "El Cheapo" crimper off the Internet?

[smile]

Just adding my 2 cents worth.

A good crimp connection is very good indeed, but a bad one is an invitation to trouble.
The  thing is, if manufacturers can't get it right, what chance has someone with an "El Cheapo" crimper off the Internet?

None i suppose, except solder crimped connection and make proper stress relief.

[smile]

I too have seen very many failed factory crimped connection in automotive stuff. They do not use proper factory tin plated wire, and they do not use any sort of grease to protect the crimped wires from oxidation relying on the imaginary gas tight myth to work in their favor. Well somehow this makes bad results after connection oxidizes.

[smile]

But still even if you agree on soldering after crimping that still has one problem, what multi crimper to use. Nobody want's crap tools, and since Engineering brand was said to have terrible quality then what's left? Are you sure this was not quality issue with your item, did you contact manufacturer what did they say?

[mikerj]

I too have seen very many failed factory crimped connection in automotive stuff. They do not use proper factory tin plated wire, and they do not use any sort of grease to protect the crimped wires from oxidation relying on the imaginary gas tight myth to work in their favor. Well somehow this makes bad results after connection oxidizes.

You are making many false assumptions.  A correctly formed crimp, whether performed by a hand tool or a hydraulic tool forms a gas tight, cold welded connection.  Not only does this avoid vibration problems, it also forms a lower resistance than a soldered connection.  If you doubt this, then you'll have to explain why the vast majority of safety critical applications use crimps rather then solder. 

I used to work for a company making railway signalling systems, and we had systems with many hundreds of special fail safe signalling relays, all hand wired using crimped connections.  Each crimp tool would be tested every day by forming a crimp which would be inspected and pull tested.

Even a gas tight connection will eventually succumb to corrosion if exposed to moisture, why do you suppose that external connectors on cars tend to be sealed?

[nctnico]

I can say that Engineer PA-09/PA-21 or PAD series crimps better than KNIPEX own video.
http://tech.mattmillman.com/info/crimpconnectors/

But you must agree that Engineer crimps are not airtight. As such if Japan crimp tool can't replace OEM and the OEM costs 300-500Eur for single piece of die, then crimping its crazy nonsense if you are not a factory.

I own PA-09 and can say it's a piece of crap. Very unreliable tool. I even filed it a bit, so it could close tighter. Crimps it made were very loose and wire often could be pulled out of connector easily, with applying minimum force.

I agree. You need a crimper with a ratcheting mechanism. These can apply the correct pressure due to their construction. The cheap ones are in the $50 ballpark though and you'll need the right one for a particular type of contact.

[tooki]

…and you'll need the right one for a particular type of contact.

Indeed. I think one of the big problems with cheap Chinese crimpers (aside from the huge variability in quality) is that the descriptions are so vague, with no specs to speak of, that you don't know whether you've actually got the right tool for the connectors in question.

For example, the various "Dupont" crimpers and terminals you get on eBay vary from totally compatible to totally incompatible. They look OK at first glance, but in fact they may not be designed for each other, and the wrong combination produces terrible crimps.

[smile]

You are making many false assumptions.  A correctly formed crimp, whether performed by a hand tool or a hydraulic tool forms a gas tight, cold welded connection.  Not only does this avoid vibration problems, it also forms a lower resistance than a soldered connection.  If you doubt this, then you'll have to explain why the vast majority of safety critical applications use crimps rather then solder.

1.hand tool...forms a gas tight, cold welded connection.
Well I would like to see such demonstration video, not some advertisement either.

2.If you doubt this, then you'll have to explain why the vast majority of safety
critical applications use crimps rather then solder.

When you consider savings on not having to make OSHA proper soldering work places in a factory for every worker, not having to make trainings, saved money on solder itself, last time I checked it was not cheap.

The crimp method is better in factory, not for DIY or electronics hobby like were here do. I thought thread title reflects this.

"Crimp *and* solder a crimp connector? Good? Bad? Why?"

Good? - better connection (lower resistance) then simply crimped
(I'm not taking into account proper 500Eur crimp tools here)
Bad? - yes can be bad if proper strain relief is not made
Why? - because DIY and hobby electronics still demands for proper low resistance reliable connections. And you can make them either with 500Eur crimp tools, or soldering the connection after crimping with say Engineer PA-09/21.

The resistance for this soldered vs. factory 500Eur crimp tool made connection will be the same.

[smile]

Another thread has some valuable input to the topic.
https://www.ericthecarguy.com/kunena/9-ETCG-Suggestion-Box/52531-solder-vs-crimp

quote:

"I work in the aerospace industry (think launchpads, not runways) and we use crimps and soldered joints fairly interchangeably. Initial assembly and bench-work is typically soldered. Yet while making repairs or modifications on the spacecraft, we use crimp connections almost exclusively. This is because it's easy to reproduce a functional joint in difficult to reach places, or from uncomfortable working positions.

The crimpers I use at work span many brands and are routinely calibrated by our in house metrology lab."

Few posts above I was told that small crimp connectors should be more easily made gas tight because of small area right, metals should fuse together etc.
Now to verify this I took a bunch of factory crimped (with proper tools I suppose) connectors from computers and a scalpel, I dissembled the connectors without much effort, the strands were not fused together or to the connector. It's actually strange that wires pull out so easy once you know how to release them.

[wraper]

I can say that Engineer PA-09/PA-21 or PAD series crimps better than KNIPEX own video.
http://tech.mattmillman.com/info/crimpconnectors/

But you must agree that Engineer crimps are not airtight. As such if Japan crimp tool can't replace OEM and the OEM costs 300-500Eur for single piece of die, then crimping its crazy nonsense if you are not a factory.

I own PA-09 and can say it's a piece of crap. Very unreliable tool. I even filed it a bit, so it could close tighter. Crimps it made were very loose and wire often could be pulled out of connector easily, with applying minimum force.

I agree. You need a crimper with a ratcheting mechanism. These can apply the correct pressure due to their construction. The cheap ones are in the $50 ballpark though and you'll need the right one for a particular type of contact.

The issue was not pressure as such, although it's important. Dies didn't close tight enough, so crimps, especially of smallest sizes, were very loose regardless of pressure applied.

[wraper]

I did not say that wires are fused together. About being airtight, look into compression fittings. They produce sealed connections without any rubber o-rings. Metal is just pressed together, nothing gets fused.

[Psi]

I've been crimping AWG16 into female pins and then soldering them for 4 years in a product and have never had any fail.
The connector is the same kind as computer ATX plugs, just less pins