Why I Crimp And Never Solder

Ralph 123

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Re: Why I Crimp And Never Solder

LIC, I think the question is if you solder a crimped connection do you risk weakening the crimp. There is an article that says yes. Paul challenged the assertion. I said to myself "good question Paul, let's find out." So, I did some research. I found a couple of sites that talk about annealing and copper. I learned that indeed, copper strengthens when cold worked and weakens when heated. So, the question becomes, when you heat a crimped (cold worked) connection to 420F or over, have you weakened the crimp by undoing the cold working. On the face of it, it seems possible so the article, again on its face, does not seem to have been pulled out of someone's @ss as Paul speculated. <br /><br />As for the connector, if you go back and re-read the thread it will be clear why the subject came up. It had to do with the wording of the ABYC guidelines and was it possible to "properly" solder a connection and not have it be acceptable to the ABYC.<br /><br />I think it all comes back to what advice you give DIYers with limited wiring and soldering experience. People like you need no help. You know exactly what you're doing and there is little risk.
 

chuckz

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Re: Why I Crimp And Never Solder

I'm reading the same articles as you and coming up with different conclusions. This might be because I have worked with too many materials guys. My understanding is cold working materials leaves residual stress and hardens them. This effectively weakens the materials because the material has some "pre-stress" and can only tolerate the amount of additional stress required to bring the material to yield. By releiving the internal stresses the material can endure more external stress before failing. This is why materials are heat treated or annealed. <br /><br />Another example, if you weld a blade for a bandsaw the weld has a very high tensile strength but is also brittle. After welding it is annealed so it will not break while being flexed in the saw. This will make the blade last longer. Is the blade weaker or stronger after annealing? In this case stronger because ductility is important. This in generally true in high vibration environments. Softer materials will last longer because they will not fatigue.<br /><br />My advice has always been, if you're not a trained solderer, crimp. My other point is that there is nothing inherently wrong with soldering IF done properly with a good splice or termination. Both crimped and soldered connections require proper strain releif.
 

JB

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Re: Why I Crimp And Never Solder

How about welding or super glue?<br /><br />Got any experts who will explain why welded joints are the best?<br /><br />Any one ever had trouble with super glued connections?
 

Ralph 123

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Re: Why I Crimp And Never Solder

Here are a few excerpts from the article in question which Paul challenged. It's clear, I think, that you are relying on the cold working (hardening) of the copper. I think it's also clear that if you heat copper to a certain point, you soften it. The question becomes, do you affect the integrity of the crimp if you then solder it. I think you are saying no, you actually make it more reliable. These guys are saying the opposite.<br /><br />
<br />The crimping part of the tool actually comprises dies which exert a swaging action on connector and wire, effectively created a "weld". The tool was designed to confine the connector and wire so that the pressure exerted by the die was concentrated at the joint. This is why ordinary pliers are not acceptable. They will crush the connector barrel alright, but both connector and wire will squish out to the side, making a joint which is mechanically weak, and electrically suspect...<br /><br />Get a marine rated connector a your dealer's and carefully examine the inside of the barrel which receives the stripped wire. Note the grooving which is designed to grip the wire, preventing stretching, and focus the crimping pressure to effect welding action. The crimp "work hardens" the copper of the connector so that the joint is mechanically sound...<br /><br />As mentioned, crimping action work hardens the connector barrel, making the joint mechanical strong and stable. If you solder a crimped joint, you may, in heating the connector, anneal(soften) the copper, making the joint loosen. Now it is the solder only which provides the strength of the joint. But if the joint is subjected to vibration, the solder, in absorbing mechanical energy over a period of time, may crystallize, and the joint may actually fail altogether.<br />
 

chuckz

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Re: Why I Crimp And Never Solder

The problem I have with this is the author states, "you may... anneal the copper", that's true, then he states, "making the joint loose". Annealing changes molecular properties of the material, it doesn't change the shape or pressure exterted by the crimp. I have a problem with the author's conclusion.<br /><br />I done hundreds of thousands of hours of vibration testing and never seen solder crystallize and fail. Stress screening weeds out cold solder joints within 10 minutes.<br /><br />We need to find a metallurgist to discuss this with.
 

Ralph 123

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Re: Why I Crimp And Never Solder

This is interesting:<br /><br />Getting Back To Basics - Insulated Electrical Terminals<br /><br />By Jim Dunbar – Product Manager, Insulated Terminals & Splices and Tom Michielutti, Senior Product Engineer, Tyco Electronics, Harrisburg, PA <br /><br /><br />
<br />The Crimp<br />The heart of any good solderless terminal system lies in the crimp system used. This may sound simple, but to maintain electrical integrity, tensile strength and insulation properties, a sound crimping technique and system must be used. The first thing to consider is that a good crimp relies on the wire, the terminal, and the tool. If any of these items are out of the terminal manufacturer’s specs, an unacceptable crimp may result. <br /><br />The crimped interface between the wire and the terminal is considered a high-pressure, permanent connection. Again, each component of the crimp (wire, terminal and tool) contributes to the integrity and the performance of the connection. An integrated crimp ‘system’ helps a given terminal meet the stringent conditions of agency approval and requirements of UL, CSA and military specifications. At Tyco Electronics, for example, crimping technology is designed to produce numerous cold welds between the wire and wire barrel that renders a nearly invisible electrical connection. A cold weld site occurs when sufficient pressure is applied to two small, but distinct, metallic surfaces already in intimate contact. Without sufficient cold weld sites, a condition known as “static heating” prevails. Static heating is a self-perpetuating phenomenon that occurs as follows: <br /><br />Crimping takes advantage of work hardening the copper wire barrel to hold the wire in place. Mild heating of the crimp begins to stress-relieve the crimped area. When stresses are relieved, cold weld sites break. Broken cold weld sites increase the resistance between the wire and wire barrel. This, in turn, increases the temperature in the crimp area; further stress relieving the crimp. This scenario continues until the crimp area becomes overheated and may result in melted or burned insulation. <br /><br />Why Crimp?<br />Crimping can be used in the vast majority of terminal to wire applications. While other methods are considered strong mechanical connections with high-performance electrical properties, crimping provides strength under constant load in tension and severe vibration. Crimp connections tend not to crack or creep under sustained loads. Fatigue is not an issue. Since the mechanical performance of a crimp is robust and sound, the electrical properties are less likely to degrade. In short, static heating is avoided when good crimping practice is followed. <br /><br />One reason to use a terminal is its performance. Ease of assembly to the wire is another important issue to explore. Crimped terminals can be assembled with several levels of automation. From manual hand tools to power-assisted hand tools on up to semi-automatic bench crimping machines and complete harness making machines, there is an ever-increasing list of options to crimp terminals. Most crimping tools and machinery provide very repeatable, low labor content results. Hand tool crimp production rates of up to 60 CPH (Crimps Per Hour) versus thousands of CPH with power assisted tools. Some machines even integrate several processes into one system (e.g. Wire preparation like cutting and stripping). <br /><br />Crimped Connection Myths <br /><br />“Soldering or Solder-Dipping Will Improve The Connection” <br /><br />Crimps are designed to work without solder or solder-dipped wire. When solder is present in a crimp, the deformation properties change. When the deformation properties change, metal-flow, cleaning, welding and residual force also change and compromise the mechanical and electrical properties of the crimp. With diminished mechanical properties, the connection may not survive normal uses. Furthermore, as electrical performance diminishes, the perils of static heating arise. Additionally, in some cases, copper wire may become embrittled or solder wicking may affect the flexure strength of the stranded wire. By soldering a crimped connection, the process heat may compromise the crimp. <br /><br />Insulated terminals play an important role in many electrical devices. Their reliability, performance and low cost result from the design relationship between the wire, terminal and tool. This connection integrity makes them suitable for many applications. By getting back to the basics, designers will likely find a suitable insulated terminal that meets their reliability, performance and cost requirements. <br /><br />
http://www.tycoelectronics.com/prodnews.asp?ID=443
 

demsvmejm

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Re: Why I Crimp And Never Solder

Originally posted by JB:<br /> Oh good grief.
I second that, however this is good read as it is expaining the basis for so many opinions that soldering is "not acceptable."<br /><br />By the way waht is an A&D connector? Never heard the term.
 

Ralph 123

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Re: Why I Crimp And Never Solder

David, A&D is shorthand for Aerospace and Defense (aircraft, military, Space, etc.). It's also often referred to as Mil-Spec. A&D requirements are very demanding since failure could result in deaths or multi-million dollar satellites that don't work, etc.
 

glen f

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Re: Why I Crimp And Never Solder

My uncle was a submariner in the Navy. He showed me all kinds of ways to wire when I was a kid. Each was specific for a certain environment. None included solder unless on boards and all were very detail specific. I will ask him where we can get instruction from the Navy. He was an electrical engineer of some type. If works for subs itll work for us. Just let me point out Im not arguing against solder or for it, trying to find out what the navy suggests. Personally I like using both and as an ex radiator repairman for u.p.s. contracts I think solder holds up to vibration on the tubes of a radiator core as well as repetative heating and cooling. Uncle constantly stressed supporting the wires before and after the connections to ensure no stress on joints. Hope I can help us all wire better.
 

18rabbit

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Re: Why I Crimp And Never Solder

Some of the wiring on mil subs is highly specialized, i.e. they use some wire that has no other application anywhere on the planet. I was reading that most communications/interfaces on subs has gone fiber optics.<br /><br />What I want to know is does a sub need a ground plate for the SSB...or is the sub the ground plate?<br /> :)
 

rodbolt

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Re: Why I Crimp And Never Solder

yes they actually do. the sub, like a ship is actually a capacitor.<br /> stray capacitance is figgured into the design of the electronics and wiring. next topic should be on back-plane wiring :) :) now there is a killer subject :)
 

Ralph 123

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Re: Why I Crimp And Never Solder

ABYC is for "small" craft. USN ships are governed by a whole set of standards called military specifications (Mil-Spec) which are much more extensive and cover virtually every facet of the vessel including workmanship standards, component requirements, testing requirements, etc.<br /><br />Sometimes, the specs cut across all of the branches, like those for semiconductors. Sometimes they are specific to an application (e.g., limitations on the insulation that can be used on the wires in a sub due to fumes in a closed environment in case of fire)
 

JohnRuff

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Re: Why I Crimp And Never Solder

Here is my formula for a worry free wire connection.<br /><br />#1 - Slide on a piece of "heat shrink tubing" (heat shrink tubing will shrink 50% when heat is applied.<br /><br />#2 - Splice the wire<br /><br />#3 - Solder the wire<br /><br />#4 - Apply any color "finger nail polish" to the exposed wire and let dry<br /><br />#5 - Slide heat shrink tubing over splice and apply heat<br /><br />It is now strong - protected - and water proof - and worry free
 

Realgun

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Re: Why I Crimp And Never Solder

JohnRuff way wrong way. ABYC will not accept it at all it has to be crimped anything else is fine but it must be crimped!
 

JohnRuff

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Re: Why I Crimp And Never Solder

Makes you wonder why they don't build television sets using crimp connectors if they are so good :)
 

Ralph 123

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Re: Why I Crimp And Never Solder

Apples and oranges. TVs aren't subjected to the nearly the same harsh conditions as a boat. Failure isn't a big deal on a $300 item that sits still in a relatively climate controlled environment. Failure in a boat in the middle of heavy seas can cost you your life. I think if you read through the entire thread you'll understand the issues a little better.
 

chuckz

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Re: Why I Crimp And Never Solder

Realgun,<br /><br />Wire do NOT have to be crimped. Step two says splice. That splice may or may not be accomplished by a crimp.
 

jlinder

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Re: Why I Crimp And Never Solder

TVs are PC boards and soldered because of specific conditions.<br />1. Componants on a TV do not get pulled.<br />2. Componants on a printed circuit board have very little mass.<br />3. TVs deal with high frequencies. With high frequencies you want to have very repeatable circuit paths and layout so you can design the best performance. Hand wiring does not work.<br /><br />L.I. Chuck - I believe you are right - there is no specific wording that says crimp. There is specific wording that says that solder shall not be what you count on structurally. What are you suggesting for structural support? This would have to be something that if the solder joint failed the connection would still be guaranteed to be solid.
 

chuckz

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Re: Why I Crimp And Never Solder

See the fourth post in this thread.<br /><br />JB,<br /><br />All wiring in micocircuits is welded. In that application it beats soldering or crimping. Of course it requires highly specialized and very expensive equipment.<br /><br />And, as you know, super glue is non-conductive :)
 
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