Electrical connections

[Bob Weber]

41 minutes ago, Andy95W said:

Well, I've only been soldering for 45+ years which takes me back to the old Heathkit days.

I'm with JimB and the guy in the video.  I don't think I would ever trust a 1/8" solder connection in a high vibration environment as much as I would the traditional methods.

But I will keep your technique in mind for tight situations where it might be needed.

Growing up in Fraser MI, my folks were at wits end with me for destroying every toy they gave me. Finally, when I was 6, they figured out giving me kits to build was the way to go. I caught my Father and Sister with the burglar alarm experiment of my Heathkit Junior 36. I was forbidden to run that experiment again.

Edited February 18, 2020 by Bob Weber

[Bob Weber]

6 minutes ago, PT20J said:

I believe the Western Union splice was designed back in the telegraph days as a means to splice solid connector wires without solder. For small gauge wires that are soldered, the technique that Bob showed earlier would be better. You want a soldered splice to be as small as possible because makes a stiff place in the wire that can lead to stress fractures when the wire flexes. The shorter the stiff section, the better. A butt splice adds mass and can cause failure if it vibrates, so butt splices are best used where they can be supported, for instance, in a bundle of wires.

I don't understand the description of the mag ground wire. Mag P-lead wire should be a single conductor with a braided shield (the shield is for radio interference). A shield should not conduct current and thus should be grounded at only one end. I believe that Slick recommends grounding the shield at the ignition switch end rather than the magneto end.

Skip

I always like your responses Skip, The real trick to soldering is speed, the longer you dwell on the wire, the farther the solder wicks into it. My connection is less than a quarter inch long, the solder is only massed at the connection and by the technique, minimizes this as well. I run a 700° iron and use a choreboy style cleaning pad.

My offshore boat was rewired over ten years ago and these connections are everywhere in both engine systems as well as the custom panel that was installed.

"to internal combustion and wind in the face"

[Andy95W]

I'm going to grab some wire and give it a try.  I'm getting old but hopefully I can still learn some new tricks.

[EricJ]

8 hours ago, Bob Weber said:

 Is this a P lead? That's safety related and needs to be right. Unlike what they seem to be teaching the kids at school today, a properly executed solder joint will go a lot further, be less bulk, and consequentially more trouble free. Granted, they're not child proof, I routinely revisit installations and repairs I have accomplished over the last 5 decades now, and see the durability of the different methods.

FWIW, this "kid at school" is an Electrical Engineer with four decades of experience and I concur with my school's A&P instruction that a proper solderless joint will be more robust in a harsh environment than solder.   Solder has its place, but for repair or rework or installation in aircraft wiring a proper solderless connection would be my first choice.

[Bob Weber]

19 minutes ago, EricJ said:

FWIW, this "kid at school" is an Electrical Engineer with four decades of experience and I concur with my school's A&P instruction that a proper solderless joint will be more robust in a harsh environment than solder.   Solder has its place, but for repair or rework or installation in aircraft wiring a proper solderless connection would be my first choice.

When we transitioned from the KMA 20's and KX 170's to the 24's and 155's I was in heaven with the crimped connectors, far quicker and of course, more repeatably reliable with the correct tools.

I have also found a factory crimped socket in a 425 Cessna that spent the better part of three decades trying to kill its occupants.

None of this is childproof and must be held to the absolute highest standard.

All of this should be embraced as methods to be used where they can best serve the task.

At least try to stagger your crimps to avoid the wad, something I don't need to worry about due to the greatly diminished mass and weight.

Here's a pic of 4000 connections I made and then walked thru the STC process in 1991ish. I cut, broke, painted, and riveted pretty much everything you see as well. Then I flew right seat to Wichita for certification where we were done before lunch, with modification, spinning the feds mind.

[PT20J]

2 hours ago, EricJ said:

FWIW, this "kid at school" is an Electrical Engineer with four decades of experience and I concur with my school's A&P instruction that a proper solderless joint will be more robust in a harsh environment than solder.   Solder has its place, but for repair or rework or installation in aircraft wiring a proper solderless connection would be my first choice.

Guess you don’t care much for surface mount PCBs then either. 

I think it’s a matter of scale. If I were soldering wire larger than 20 AWG, I’d twist it together first. But smaller gauge wire I would want to make the smallest joint possible. 

The problem with solder is too much of too little, and too much heat or not enough.

Too much solder wicks up the wire and causes a stress point. Too little and the joint is weak or subject to corrosion. Too much heat damages insulation and connectors. Too little and you get a “cold” solder joint that will eventually cause problems due to high impedance. 

I’ve spent a lot of time and money chasing down cold solder joints on through hole PCBs and bad crimps on connector pins.

Skip

[EricJ]

8 minutes ago, PT20J said:

Guess you don’t care much for surface mount PCBs then either. 

If the joint is supported by sufficient layers of FR4 to provide a mechanical substrate, solder works fine.   That's not the case with aircraft wiring.

 

Edit:  even then, solder joints still crack on PCBs, even with all that mechanical support.

Edited February 19, 2020 by EricJ

[EricJ]

10 minutes ago, PT20J said:

I’ve spent a lot of time and money chasing down cold solder joints on through hole PCBs and bad crimps on connector pins.

I think that's why AC 43.13 doesn't say much specific about solderless connectors other than a ratcheting crimper should be used.   If the crimp is good the joint is likely to be reliable.

[MikeOH]

3 minutes ago, PT20J said:

Guess you don’t care much for surface mount PCBs then either. 

I think it’s a matter of scale. If I were soldering wire larger than 20 AWG, I’d twist it together first. But smaller gauge wire I would want to make the smallest joint possible. 

The problem with solder is too much of too little, and too much heat or not enough.

Too much solder wicks up the wire and causes a stress point. Too little and the joint is weak or subject to corrosion. Too much heat damages insulation and connectors. Too little and you get a “cold” solder joint that will eventually cause problems due to high impedance. 

I’ve spent a lot of time and money chasing down cold solder joints on through hole PCBs and bad crimps on connector pins.

Skip

SMD is a whole different situation; early days of SMD were fraught with low yields and poor reliability, but not related to the vibration issues associated with soldered stranded wire.

Even a properly soldered stranded wire to a RIGID connection point (e.g. a wire ring terminal) is just asking for long term reliability issues.  A properly crimped (gas tight) connection is FAR superior to a soldered one.  There is ALWAYS a stress point where the flexible, non-soldered, portion of the wire meets the portion of the wire where the solder HAS wicked.  In a high vibe environment (e.g. an aircraft) time is going to fatigue that interface.

BWTHDIK, just another 40+ year EE.

[Yetti]

5 minutes ago, EricJ said:

I think that's why AC 43.13 doesn't say much specific about solderless connectors other than a ratcheting crimper should be used.   If the crimp is good the joint is likely to be reliable.

This plot continues to thicken since I know more :-)     I am a fan of fast and a hot iron.  Like the old big weller guns.  Crimp connectors with a set of Kline crimpers are good too with a very small failure rate.  A pair of Snap-on Dykes for stripping wire.  the auto strippers for the smallest of wires.  Critical connections in a salty environment get a crimp then solder.  A crimp will eventually get the black stuff under it and not be good.

 

[MikeOH]

28 minutes ago, Yetti said:

This plot continues to thicken since I know more :-)     I am a fan of fast and a hot iron.  Like the old big weller guns.  Crimp connectors with a set of Kline crimpers are good too with a very small failure rate.  A pair of Snap-on Dykes for stripping wire.  the auto strippers for the smallest of wires.  Critical connections in a salty environment get a crimp then solder.  A crimp will eventually get the black stuff under it and not be good.

 

Stripping wire with dikes is poor practice regardless of wire gauge; too easy to nick and weaken the wire.  Crimp plus solder is like fingernails on a chalkboard!!!  It hurts to hear!  That is just not a good idea if reliability is a concern.

Have you gotten away with it?  Sure.  Question is, for how long?

Do you want the 10 ppm failure rate or the 1000 ppm one?

A properly crimped connection will NOT get 'black stuff' under it; it is mechanically fused and gas tight.  A soldered connector has corrosion issues due to entrapped flux residue (likely activated, exacerbating the problem), embrittlement/crystallization on top of the fatigue failure mode.

[Huitt3106]

Okay, so I made a trip to the airport today to get a better look at what I had going on. It’s not a ground or P lead that was worn. It’s a wire that runs with the retard wire. I have attached a few photos. This wire runs back to the firewall and is mounted close to the cowling with just a barrel connection dead ended.


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[Bob Weber]

42 minutes ago, MikeOH said:

SMD is a whole different situation; early days of SMD were fraught with low yields and poor reliability, but not related to the vibration issues associated with soldered stranded wire.

Even a properly soldered stranded wire to a RIGID connection point (e.g. a wire ring terminal) is just asking for long term reliability issues.  A properly crimped (gas tight) connection is FAR superior to a soldered one.  There is ALWAYS a stress point where the flexible, non-soldered, portion of the wire meets the portion of the wire where the solder HAS wicked.  In a high vibe environment (e.g. an aircraft) time is going to fatigue that interface.

BWTHDIK, just another 40+ year EE.

Spend a few decades inside an old FCS 810 computer with its 26ga stranded wire soldered into the thru holes of a bunch of 1960 vintage boards. I have chewed up engineers for years by the way, my favorite memory was a guy Roswell W Ard, a mechanical engineer, I was performing a service bulletin on his KAP 140 in a single Cessna for him when he challenged me about the way I was removing the pilots seat. He was telling me how I was doing it wrong by not completely disassembling the roller assemblies, he clammed up when that seat was on the floor quicker than he could tell me what I was doing wrong. My engineering abilities and capabilities have been honed since I was 6, I have built hundreds of engines including race winners, restored several fixed and rotor wing aircraft, boats, cars, houses, I'm sick of someone telling me they are an "engineer".

 

The most gratifying experience with an Engineer was with a Filipino I am working with thru an interpreter, about three translated answers into the conversation, the universal response of OOHHH was heard on the call, after 15 minutes he was dancing with what he just learned.

[Yetti]

1 hour ago, MikeOH said:

Stripping wire with dikes is poor practice regardless of wire gauge; too easy to nick and weaken the wire.  Crimp plus solder is like fingernails on a chalkboard!!!  It hurts to hear!  That is just not a good idea if reliability is a concern.

Have you gotten away with it?  Sure.  Question is, for how long?

Do you want the 10 ppm failure rate or the 1000 ppm one?

A properly crimped connection will NOT get 'black stuff' under it; it is mechanically fused and gas tight.  A soldered connector has corrosion issues due to entrapped flux residue (likely activated, exacerbating the problem), embrittlement/crystallization on top of the fatigue failure mode.

done properly, you can strip and not nick the wire with dykes.  The same cannot be said about the automatic strippers.   The auto strippers will also nick the wire in a worse way than a pair of dykes.  Accelerating failure rates. 

Do you have any actual experience in a marine salt water environment?   I have probably 40 years of actual experience 

High humidity environment, High heat and cement dust?

My best EE story is the EE was  mad that the solar field having mismatched power outputs.    Big field, Half the field could be covered by a cloud.   Forgot about clouds.

[PT20J]

1 hour ago, Bob Weber said:

19Spend a few decades inside an old FCS 810 computer with its 26ga stranded wire soldered into the thru holes of a bunch of 1960 vintage boards. I have chewed up engineers for years by the way, my favorite memory was a guy Roswell W Ard, a mechanical engineer, I was performing a service bulletin on his KAP 140 in a single Cessna for him when he challenged me about the way I was removing the pilots seat. He was telling me how I was doing it wrong by not completely disassembling the roller assemblies, he clammed up when that seat was on the floor quicker than he could tell me what I was doing wrong. My engineering abilities and capabilities have been honed since I was 6, I have built hundreds of engines including race winners, restored several fixed and rotor wing aircraft, boats, cars, houses, I'm sick of someone telling me they are an "engineer".

 

The most gratifying experience with an Engineer was with a Filipino I am working with thru an interpreter, about three translated answers into the conversation, the universal response of OOHHH was heard on the call, after 15 minutes he was dancing with what he just learned.

Got my undergraduate EE degree in 1975. Masters in Computer Science came later. First job was at ESL, a company started by Bill Perry (long before he was Secretary of Defense) making signal processing stuff for the government. We had a lab with a lot of seasoned technicians. I learned early on that while we engineers were arguing the finer points of Maxwell's equations, the techs had found the problem and fixed half a dozen circuit boards. Engineers design stuff; technicians are better at fixing stuff. 

I agree that crimp connections are better than soldered because crimp connections are engineered. That means that properly crimped, all the variations of technique are removed. But... the biggest problem is that each crimp connector pin requires a specialized crimping tool and the good tools are really expensive. A good avionics tech has a few thousand dollars invested in crimpers. I just chased down an intermittent problem with a Navcom that was caused by a bad crimp. Soldering irons and solder are cheap and effective if you know how to use them properly.

Skip

[Yetti]

Black stuff that insulates.   battery terminals are a clamped engineered product.  I don't how many cars I have walked up to.  Popped the terminal off made it shiny bright.   Put back on.  Oh look no more dead battery.

[Bob Weber]

Just now, PT20J said:

Got my undergraduate EE degree in 1975. Masters in Computer Science came later. First job was at ESL, a company started by Bill Perry (long before he was Secretary of Defense) making signal processing stuff for the government. We had a lab with a lot of seasoned technicians. I learned early on that while we engineers were arguing the finer points of Maxwell's equations, the techs had found the problem and fixed half a dozen circuit boards. Engineers design stuff; technicians are better at fixing stuff. 

I agree that crimp connections are better than soldered because crimp connections are engineered. That means that properly crimped, all the variations of technique are removed. But... the biggest problem is that each crimp connector pin requires a specialized crimping tool and the good tools are really expensive. A good avionics tech has a few thousand dollars invested in crimpers. I just chased down an intermittent problem with a Navcom that was caused by a bad crimp. Soldering irons and solder are cheap and effective if you know how to use them properly.

Skip

Early in my career I worked at a resistor manufacturer as a service tech on the production equipment, one of the tasks was to troubleshoot a failing Double Calvin Ratio Bridge panel. As I evaluated the issue I found a very simple fix that the resident EE refused to accept. There were 23 stations of these bridges inop and out of production. I spent an hour a shift for 6 weeks verifying that my trim potentiometers were as stable and far more efficient to keep the bridges in spec while testing the parts headed to the space shuttles and cruise missiles.

He did not react well when his hind quarters were handed to him.

Some of the most talented minds, and some of the most positively planted heads....

I chased a very abrupt pitch up issue in a 425 Cessna for literally years, I finally found an over crimped (at the factory) socket at the rear pressure bulkhead that was arcing for years, it was the power to the pitch servo and a 1000 series ARC autopilot does not react well to this. They did not teach me to look for that in my factory training classes. Crimps are wonderful until your bit by a bad one.

[Yetti]

2 hours ago, Huitt3106 said:

Okay, so I made a trip to the airport today to get a better look at what I had going on. It’s not a ground or P lead that was worn. It’s a wire that runs with the retard wire. I have attached a few photos. This wire runs back to the firewall and is mounted close to the cowling with just a barrel connection dead ended.


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What was the point of putting new wires on if they are not going to be routed properly.    the frayed wire looks like a ground braid with an inner core.   Probably just shrink wrap it for a fast fix..   The bottom pic with the wire over the safety wire is wrong routing.   Get 2 adel clamps and connect the oil hoses and get rid of the tywrap on top of the fire sleeve.   Reroute the thermocouple wire away from the spark plug wires in the first photo.   The tywraps on the spark plug wires are wacky.   More than likely the wires you are holding are not long enough to route properly.   You are going from a stable platform to one that moves quite a bit in the engine mounts.   You paid good money ask them what they see wrong if they don't then get someone to do it right.  Random use of tywraps annoys me greatly.

Edited February 19, 2020 by Yetti

[Bob Weber]

5 minutes ago, Yetti said:

 Random use of tywraps annoys me greatly.

My Dermatologist was very stern when asking about all the scars on my hands.. Tywraps and airplanes was my response, I'm not on suicide watch.

[EricJ]

2 hours ago, Huitt3106 said:

Okay, so I made a trip to the airport today to get a better look at what I had going on. It’s not a ground or P lead that was worn. It’s a wire that runs with the retard wire. I have attached a few photos. This wire runs back to the firewall and is mounted close to the cowling with just a barrel connection dead ended.

Do you have a Shower of Sparks system or do you know what your ignition starting system is (SoS, impulse coupling)?   Is it possibly a tach wire?

Either way a properly crimped butt splice could be used.   Some heat shrink over it would be good, too.   The repair will have to be signed off, so consult whoever might be doing that.

[Bob Weber]

3 hours ago, Huitt3106 said:

Okay, so I made a trip to the airport today to get a better look at what I had going on. It’s not a ground or P lead that was worn. It’s a wire that runs with the retard wire. I have attached a few photos. This wire runs back to the firewall and is mounted close to the cowling with just a barrel connection dead ended.


Sent from my iPhone using Tapatalk

I would do a solder splice as I have outlined earlier and call it good. Crimp it if you want..

[Huitt3106]

What was the point of putting new wires on if they are not going to be routed properly.    the frayed wire looks like a ground braid with an inner core.   Probably just shrink wrap it for a fast fix..   The bottom pic with the wire over the safety wire is wrong routing.   Get 2 adel clamps and connect the oil hoses and get rid of the tywrap on top of the fire sleeve.   Reroute the thermocouple wire away from the spark plug wires in the first photo.   The tywraps on the spark plug wires are wacky.   More than likely the wires you are holding are not long enough to route properly.   You are going from a stable platform to one that moves quite a bit in the engine mounts.   You paid good money ask them what they see wrong if they don't then get someone to do it right.  Random use of tywraps annoys me greatly.

The previous owner was the one who had the work done/ did the work not me. I purchased this airplane back in August.


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[Huitt3106]

7 hours ago, EricJ said:

Do you have a Shower of Sparks system or do you know what your ignition starting system is (SoS, impulse coupling)?   Is it possibly a tach wire?

Either way a properly crimped butt splice could be used.   Some heat shrink over it would be good, too.   The repair will have to be signed off, so consult whoever might be doing that.

I'm still learning all of the updates that were done on the airplane but I don't think its the original SoS system.  I do not have the push and turn ignition if that helps (Just turn the key!).  

[Yetti]

9 hours ago, Bob Weber said:

My Dermatologist was very stern when asking about all the scars on my hands.. Tywraps and airplanes was my response, I'm not on suicide watch.

Pro trick one is the small flush cut snap on cutters.   Pro trick two is finger nail clippers.   Even if you use a pair of dykes and they are cut parallel to the wire instead of at an angle like pungi stick is ok in a pinch.

For the dynon install I old school cloth tied a bunch of stuff.   almost as fast as a tywrap.   tywraps for some hard to get to places.   When you can put on a typwrap one handed in a blind spot that is when you have a masters degree.

[Yetti]

13 hours ago, Huitt3106 said:

Okay, so I made a trip to the airport today to get a better look at what I had going on. It’s not a ground or P lead that was worn. It’s a wire that runs with the retard wire. I have attached a few photos. This wire runs back to the firewall and is mounted close to the cowling with just a barrel connection dead ended.


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In just this one photo I can see 3 places you are going to have future problems.