Crimp or solder (or both)

[Deang]

I had a nice chat with Bob Crites tonight. He was sent a set of my Heresy networks from Dee Edwards, and while checking them out discovered that a part (I can't remember if it was the tweeter section or squawker section) of one network was 3db down compared to the other. He mentioned that my "bad" habit of soldering everything down at the terminal strip made troubleshooting impossible unless he desoldered everything. He passed on that a good crimp is as good or better than a solder joint, and so I spent an hour or so cruising around the net reading up on it. Turns out he's for the most part right, and crimping is the preferred method in the aircraft and aerospace industry. One article did say that even though this is the case, the employed crimping methods are not available to us (though the writer didn't give any information as to what he meant by that). I sure learned a lot about crimping tonight.

http://www.aeroelectric.com/articles/rules/review.html

http://www.carcraft.com/techarticles/85700/index4.html

Dee, I'll send you an email to confirm -- but if you read this please send those boards back for an exchange. The caps in those boards had seen considerable use from all the cap comparison testing I did, and it's possible one of them became damaged. I'll send the autoformers back to Bob after I strip the boards so he can check them out. I'll build you some new boards from the ground up.

[djk]

What are the credentials of the author in the car magazine?

The aeroelectric author and the rebuttal author are both right and wrong on several points.

The company I work for makes the CURRENT avionics for Boeing. The connectors are soldered, not crimped. The school to learn how to strip the wire and solder the connector takes four days! Regular re-certification is required.

The faston connectors so praised by the one guy make such a poor connection (even when new) for SPEAKERS, that I always cut them off and solder the connection.

Klipsch went to using faston connectors around 1985 for most of the new models, it made production easier.

Removing these makes the image more stable, and the speakers have less low level 'grunge' and sound cleaner and quieter during soft musical passages.

Strangely, it makes the speakers SOUND less efficient because of the dynamic contrasts on quiet passages. Then the loud passages come in, and they sound even more dynamic.

As far repair operations go, just cut the wire at the driver. There is enough extra to do this five of six times without having a problem with too short of wire.

[Duke Spinner]

I ....

must side with Dennis ....

[markus111]

I work in the auto industry, where we had one of the most expensive recalls in history due to bad connections. We performed a 1 year study (no joke) on how to properly put a connector on a wire to achieve the best connection and conductivity. The conclusion was that you crimp the wire so that the copper wire deforms, and then solder over it. Deformation of the wire is important for greatest surface area contact. Picture a multistrand copper wire which consists of 20 or more individual round strands in a bundle. It should be crimped with a crimper that can smash the round wires into approximately hexagonal shape so that there is a high amount of surface contact, and little air space between the strands. It is important to have the right size connector for the wire diameter. Then, you solder over the connector to fill in the remaining air space. This approach was found to give maximum conductivity as well as protection from oxidation.

Mark

[fini]

Great topic, Dean. I've wondered about this, too. The first author's point that all the copper piping in your house relies on solder for structural connections is a good one.

Specifically, what's a good crimper? You know, brand, model number, etc., or should I look for a particular style? I usually just use lineman's pliers.

[colterphoto1]

Good topic,

I use needlenose pliers, smaller jaws yield more pressure on a smaller area, better crimp imho.

Michael

[Frzninvt]

I trust soldered connections over crimps any day. Much more solid connection, whether in my car audio system or home system. Crimps can fall off, soldered connections won't.

[Raptor22]

Interesting topic,I have been in the aviation maintenance field for 30 years and this has been juggled back and forth. Markus, I have always been led to believe that for a proper solder joint the conductor should been tinned with solder first. However, if the purpose of the soldering you refer to is to encapsulate the joint rather then provide the electron path then I might defer. A crimping tool is required in order to properly seat the connection, a flat jawed tool cannot perform this task.

[BEC]

For good crimps, you need a ratchet crimper.

Bob Crites

[colterphoto1]

What is that Bob, an $80 tool? I have one for the RG series and it was rather expensive.

[BEC]

Michael,

Not all that expensive.

Bob

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=360-680

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=360-684

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=360-686

[Aggie Klipsch]

As an engineer we tin the leads and then crimp. Of course this depends on temp. considerations. As we are not putting the connectors in a downhole situation I would recommend tin and crimp. Cheers

[customsteve01]

In aviation we use crimpers the most because we are mostly dealing with either splicing a wire or working with cannon plugs. if we are terminating a wire to a switch or other device it will be soldered.

the crimp tool we use are calibrated yearly and they will crimp the terminal on 4 sides not just squeezing on 2.

DMC makes a toolkit that looks like a suitcase and weighs around the 60 pound range that has all the tools to perform crimps and removing pins from cannon plugs for a variety of aircraft models. the tool kit for the aircraft we fly costs around $6100.00.

There website is

DMCtools

Steve

[markus111]

----------------

On 5/17/2005 8:42:01 AM Raptor22 wrote:

Markus, I have always been led to believe that for a proper solder joint the conductor should been tinned with solder first. However, if the purpose of the soldering you refer to is to encapsulate the joint rather then provide the electron path then I might defer.

----------------

Deforming and tinning provide the same basic purpose of getting through the thin layer of oxidation that exists on the surface of the copper. We found that deforming it first worked better in our application, followed by soldering to seal it. Tinning is definitely preferred at home, as most people won't have the right crimpers for every applicaton in their home workshop. We have about 30 different sizes at work.

Mark

[D-MAN]

In the Navy Electronics "A" school, we spent a couple of weeks learning how to solder and splice. Crimping was never used nor taught.

Crimping for an electrical connection instead of soldering is subject to other considerations, such as environment, strain, humidity, temperature changes, acidic content, etc. where solder would be subject to a higher degree of corrosion or oxidation.

Seems that it is a economic decision rather than an engineering one (except for heat-sensitive products). Better electrical connection is achieved by solder, but that will cost more because it take more time to accomplish.

I would prefer to use solder connections whenever possible in home electronics.

DM

[blindman]

I participated in the building of satellites and extra-terrestrial probes (e.g. GPS and planetary space vehicles) from 1980-1990. I also worked on several weapon systems for the Department of Defense that I am not allowed to name.

As you might well imagine, satellites are built to meet very stringent standards. It is almost impossible to fix them if they don't work the first time since they are orbiting the earth or journeying outside of our solar system. Plus they must be able to withstand the violent forces during the launching process.

None of the wired connections in these space vehicles were crimped. None, nada, zero.

They were either soldered (after precise pretinning) or the connections were made using "wire wrapping" techniques.

The Quality Inspection included visual, laser, and reflected heat transmission techniques. Also a certain percentage of every connection was inspected via destructive testing to insure the efficacy of the joining technique (i.e. mechanical pull-force testing; and diamond saw cross-sectioning to permit visual inspections of the interior of the connections utilizing high powered electron microscope examination of the joints).

All of the personnel who performed the solder and/or wire wrap connections had to undergo a rigorous 2 week training process every year. Samples were prepared during the training, and those who failed to meet the standards, were out of a job!

My credentials: my job was to train the training instructors, train and certify the quality control inspectors, and to write the assembly instructions and QC procedures. Therefore I had to be able to perform the tasks at least a little bit better than each of the assemblers and inspectors.

Note: the satellites I helped build...are still in service. I repeat: n-o c-r-i-m-p-i-n-g. But I must also point out that every connection was also coated or "potted" with a protective coating material to protect it from the "outgassing" of adjacent materials and/or galvanic reaction corrosion. The protective coating materials also served to "hold things together" by the sheer force of enveloping everything with a layer of rubber, silicone, or plastic.

[Seadog]

I worked for 5 years as a manufacturing engineer supporting a wire harness and electrical bench shop for a military fly-by-wire aircraft. Thousands of critical wire terminations were crimped. The crimpers were similar to the example shown by Customsteve01. Four precision indentors deform the barrel of the contact to create a highly reliable crimp.

We used to calibrate the crimpers every 26 weeks (13 weeks for automated equipment). The calibration was essentially a mechanical pull test. On a properly crimped terminal, the conductors will break before the crimp lets go. Good crimps are hard to beat.

I went through the hands-on certification training for crimping and soldering (probably 2 weeks x 8 hours of training). I have not worked in that industry for over 16 years, but today when I terminate a wire, I crimp AND I solder (just in case!).

[blindman]

My experience encompasses an evaluation of crimping techniques, which included the watchful eyes of United States governmental agencies. Our results indicated that the cross-sectional de-formation of the wires during the crimping, or "pinching" process, lead to an increase in the failure rate. Therefore, we tended to stick with joining techniques that did not change the physical characteristics of the wires/components.

Think about it, during the process of crimping, you are creating a "stress point" at the crimp. Not unlike how when you crease a piece of paper before you tear it in half...the crease allows the tearing action to follow the path of least resistance...

Still, for the sake of argument, I must repeat that the projects I am referring to had to meet standards that greatly exceeded the requirements of any non-space related project.

I wholeheartedly agree, and endorse 100%, the technique of crimping-and-soldering, for projects that you can re-do (and periodically re-inspect) if the connection should fail to pass the "test-of-time". I would not crimp without also soldering, unless cost (versus reliability) was the primary motivation.

Your Mileage May Vary...

[Erik Mandaville]

I have a crimping tool similar to what Bob displayed, and it's one of the most frequently used tools I have for making connections where spade or ring terminals are used -- input-to-crossover terminals, crossover output to driver connections, single point ground connections to a chassis, that sort of thing. Solder is not a particularly good conductor, and as such shouldn't be relied on for the electrical aspect of a connection. I was taught to make a very positive mechanical connection first, and then SEAL the joint with solder, which both prevents the connection from coming loose and seals it against oxidation. When I was building more involved with building crossovers and speakers about 12 years ago, I would follow up soldering with a wax crayon held against a freshly made joint. The heat would melt the wax so that it would provide another layer of protection against oxidation and corrosion (something which I would really rather not bother with now....)

For crossover terminal boards, Radio Shack sells exactly what's needed for 3 drivers and an input into the network. I use ring terminals from the output of the network to the drivers, where those have been first tightly crimped and then sealed with solder. The stock Klipsch spades on driver leads are too wide for the RS terminal strips, but I replace those with either slightly narrower spades or ring terminals. I use Teflon insulated, silver-clad-copper solid conductor cabling to the drivers, and a simple loop of wire can work just fine on a screw-down terminal board. It just doesn't look very nice. Appropriate ring terminals crimped and soldered works well for me, though.

I do the same thing with speaker cables -- but just prefer to NOT tin leads before crimping and soldering the termination. I use a good quality stripping tool, and then immediately tightl-crimp-solder the spade over the fresh copper. This all started when my dad scolded me for tinning leads first. "Don't tin the leads before making the connection!" he said. "Tinning is good for transformer leads after the varnish is removed (or use a solder pot), but don't do that for signal wiring in audio!" So, whether that's the right or wrong approach, that's what I've been doing!

I've got a couple of receiving radios -- huge things -- that were built during the second world war, and are works of art in terms of electrical wiring and beautiful soldering technique......almost exclusively done by very skilled women. My dad (sorry I keep referring to him, but he is someone who has extensive knowledge with this stuff)explained to me years ago that even complex circuits like those radios, which make some audio amp schematics look like electronic children's books written with large and simple writing, should work without solder, based on the integrity of the mechanical connections alone. Solder is then used to permanently hold the 'sound' connection in place and protect it against the environment.

And! I know people who rely on crimping only, and say that it works well for them!

Erik

[djk]

When you are talking Klipsch speakers and crimping, you're talking the newer models with faston connectors.

It doesn't matter how good the wire is hooked to the connector when the connector itself sucks wind (from an audio standpoint).