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Crimp or solder D sub pins?

Vansconvert

Well Known Member
Which is the way to go? I heard solder is better, and I heard crimping is better (easier for sure, but better?). Anyone know what places like SteinAir and Aerotronics are doing?
 
Almost all shops will crimp i believe. I soldered when i installed my efis and havent had any issues but the last couple things i have installed/updated i have crimped.
 
Which is the way to go? I heard solder is better, and I heard crimping is better (easier for sure, but better?). Anyone know what places like SteinAir and Aerotronics are doing?

Crimp. All the Aerospace giants use crimps for the following reasons.

Solder is NOT better. Takes more skilled worker, longer time, more steps, and if not done correctly, there are more failure modes.
 
And get the machined barrel crimp pins -

449342.jpg


Not the cheaper stamped version -

CP20S.jpg


They will be much easier to work with. Steinair has them.
 
If you don't have a background in electronics (meaning that you're very handy with a soldering iron), go with crimps for subD pins.

I've had several careers as an electronic tech. I've had a *lot* of practice using a soldering iron. I started out building harnesses using solder type subD connectors. I soon switched to crimps. I still solder a lot of stuff, but crimp subD's win for me for a number of reasons. They are much faster to assemble, they allow repositioning the pins (don't think you won't need this), and strain relief for individual pins is inherent in the connector body.

If you've never built the solder type subDs (and even if you have...), it's easy to destroy connectors due to overheating the plastic insulator material that separates & aligns the pins.

Hope that helps explain why crimps really are better, at least for subDs.

Charlie
 
solder or crimp rule

Some time ago I heard the following general rule:

Solder when corrosion is the main problem, crimp when vibrations is the problem.

Makes sense to me, I solder most boat stuff, crimp most airplane stuff!

Do use the machined pins and special crimper though, much better and easier in the long run.
 
Another data point

We've soldered around 20,000 D sub connectors for our ECUs and other controllers (wire harness ends), some of these in service over 20 years and millions of hours in some severe environments. Zero failures.

If done right, extremely reliable.
 
Both methods are reliable if done correctly. Use whichever one suits your skills, experience and equipment available.
 
Both methods are reliable if done correctly. Use whichever one suits your skills, experience and equipment available.

Exactly.

My earlier post worked on the premise that if you need to ask, you probably don't have the skills, experience and equipment to get consistent good results. And there remains the issue of easily corrected wiring errors and easily modified harnesses, which can be a factor as avionics are updated/changed.

And to the vibration issue: That's an old hangar tale that just won't die. A crimped connection has exactly the same vulnerabilities as a soldered connection to vibration. Both require proper support outside the joint to avoid flexing fatigue failure at the joint. Yes, solder may wick up the wire. But proper support outside the joint protects the wire from flexing. Crimped joints have an even bigger vulnerability; there's a stress riser at the crimp itself and if not properly supported, that's where the wire will break.

Charlie
 
As an avionics tech in the Navy, I was taught to solder connectors with fixed style pins that had cups specifically designed to be soldered. After soldering, we "Potted" them with proseal. They went in high corrosion areas, like wheel wells. It was a major PITA to do any work on those connectors.

For the machined pins and sockets, designed to be inserted and extracted from the connector, we always crimped, using specially designed tools for this purpose. Those pins don't have the cup style designed for easy soldering. You can solder them, but why would you?
 
I have noticed with Tefzel, it is difficult to tell if solder has wicked up the insulation compared to less stiff insulation material. Just an observation.
 
I have noticed with Tefzel, it is difficult to tell if solder has wicked up the insulation compared to less stiff insulation material. Just an observation.

Unless you go nuts with the heat, the solder usually only wicks up less than 1/2" and usually less. The end of the connector shell is at least 1" back and it prevents that 1" or so of wire from moving or flexing at the joint, soldered or crimped.

Larry
 
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I have noticed with Tefzel, it is difficult to tell if solder has wicked up the insulation compared to less stiff insulation material. Just an observation.

And that matters because...? (Really analyse the full installation of the terminal and wire before answering.)
 
And that matters because...? (Really analyse the full installation of the terminal and wire before answering.)

Just an observation. Larry covered it for this particular application.

Regardless, back in my Electronics Tech days I built a lot of high density harnesses. Joints that wicked where rejected. Good practice is still good practice and I don’t accept poor joints in my own work but you can certainly argue supporting the joint trumps that.
Wick to your hearts content....
 
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Way back in the Stone Age when I went through DOD solder school for an acceptable solder joint, solder was not allowed to wick up under wire insulation at all. We has little heat sink clips (like alligator clips without the teeth) that we clipped just behind the pin. We actually had to leave about an eighth inch of bare wire showing behind the pin so the inspector could verify solder had not wicked up under the insulation. The reason was if solder wicked under the insulation then the ?stiff? to ?flexible? transition was hidden from view. This transition from stiff to flexible was where the wire would inevitably break. When troubleshooting if it broke right behind the pin you could see the break if it broke under the insulation troubleshooting got a lot more interesting....
 
Of course, the *probability* of breaking at all went up by several hundred percent because there was no strain relief protecting the stress riser at the joint, but you could certainly see the failures more easily...

;-)
 
Crimp

Crimp everything. Just finished all my wiring. I crimped everything because crimping actually forms a cold weld. Works great. Oh I did have to solder the ELT plug because of the way it was made.

PS, I also repair AV cables which are all soldered and the joints are always breaking.
 
I've seen plenty of broken soldered ends on pins. When you solder the wire in the pin it makes a solid peak to the flexible wire strands. Enough vibration and the strands will all break. Crimping allows some movement in the connector. The problem with some crimping is it's not done right and the wire can pull out of the hole. A good practice is to pull the wire a little after the crimp to make sure it's tight.
 
Yes. When soldering, the solder wicks up the stranded wire and causes a weak point where the solder ends. I've seen a lot of wires break at at that point.
 
On D Subs, the solder is nowhere near where the wires flex outside the shell where the strain relief is.



This is how we build ours and as I said, millions of hours, zero failures.
 
Those aren't crimp connectors, those are solder connectors. And heat shrink is a must when using this type.
 
Those aren't crimp connectors, those are solder connectors. And heat shrink is a must when using this type.

I know they are solder type... I built this one and thousands of others like it.

The thread topic is crimp or solder D Sub pins.
 
I've seen plenty of broken soldered ends on pins. When you solder the wire in the pin it makes a solid peak to the flexible wire strands. Enough vibration and the strands will all break. Crimping allows some movement in the connector. The problem with some crimping is it's not done right and the wire can pull out of the hole. A good practice is to pull the wire a little after the crimp to make sure it's tight.

Again, old hangar tales.

Slice open a crimp with a diamond saw and you will see the same solid peak (assuming the crimp was made correctly). And if you use a 'bare' crimp sleeve (no grab of the insulation in the crimp and/or external sleeve (typically plastic) that extends away from the joint, over the insulation), and vibration/movement of the wire relative to the joint will break the strands at the joint, just like a solder joint. Structurally, what we are discussing really isn't any different from arguing about the relative merits of rivets vs welds. Do both right, in the right design, and it doesn't matter. Is the structural integrity of an Eclipse jet poorer than any of its riveted competitors?

I confess; I like solder joints. Like Ross (but in different fields), I've done thousands, across 5 decades. I feel like I have a pretty good handle on whether they work or not, and what can go wrong with them.

But I recognize that sometimes it can make sense to trade some money for time. Or, for the inexperienced, trade some money for a hedge against a lack of experience. A *quality* crimp system can allow an inexperienced person to make consistent, reliable, strain relieved connections. I, or Ross, or almost anyone else, with proper training and practice, can can make soldered connections that are equal in quality in every way to those crimped joints. But we'll never be able to do it as quickly.

Charlie
 
Just to pile on.... crimp, crimp, crimp.



The electrical connection is excellent, the termination is fast, and mechanical robustness are all winners.


If it's good enough for satellites and the space shuttle, it's good enough for your bird (100% crimped on mine, thou I had to spend a bit extra for contact and connector bodies. Worth ever penny)
 
I have to say there have been times in the tail or in corners of the cockpit where I didn’t really feel like getting personal with a hot iron.
 
I wanted to use crimps, I really did. I can see how fast it is, how nice to be able to quickly remove the pins to reposition, or to pass the harness through a bulkhead and then re-assemble in the connector. I even had available to borrow from work the expensive crimping tool and an assortment of positoners.

Absent any mentoring from an experienced avionics technician, I confess I could not sort out the bewildering miriad of specifications for what positioner to use with what crimper for what pins. I had no confidence that I could produce quality crimps when I couldn't even sort out which combination of the tools I was supposed to use. Not every avionics device was very clear at all about which tools to use. ( I have to say Garmin does a pretty good job trying to help out with this). I used to say to my self that if a high-school graduate that joins the Air Force and becomes an avionics technician can figure this stuff out, why can't a PhD in Aerodynamics that has done all kinds of sophisticated instrumentation installation for wind tunnel testing figure this out?

So, in the end, I soldered everything. Having heard all the hangar tales, true or not, I was careful to have good strain relief clamping on the backshell of each connector. And yeah, in a few places, forced to apply heat for a long time, some of the plastic bodies of the connectors show a little bit of heat distress. Always tested good. Everything works, and continues to work fine after 500 hrs.

But I really wish I had someone to sit down and say, "use this positioner in this tool with these pins" and I would have crimped everything. And if/when I redo my panel, I will scream for help here, and maybe someone can tell me what tools to use.
 
And the color bands? The crimp pins have color bands reminiscent of the color code system for resistors (BBROYGBVGW) (The mnemonic for remembering this sequence is NSFBSK).

But what do the color bands mean? Range of wire gauge accepted? A clue to which positioner to use? Code for brand name? Date of manufacture?

I'm whining because it is rare that I feel so left out from the anointed priesthood.
 
No need to join the anointed ones

And the color bands? The crimp pins have color bands reminiscent of the color code system for resistors (BBROYGBVGW) (The mnemonic for remembering this sequence is NSFBSK).

But what do the color bands mean? Range of wire gauge accepted? A clue to which positioner to use? Code for brand name? Date of manufacture?

I'm whining because it is rare that I feel so left out from the anointed priesthood.

No need to be left out. You don't even have to join the secret society.

The color bands are part of the mil-spec and are on the good machined pins/sockets.

There is even no need to remember them though - or buy the secret decoder ring - since the three we use 99.9% of the time are sold by Stein so you can just use the pictures on his web site. :D

Tooling is also covered by Stein, one low cost tool for regular Dsub pins and a positioner for it (no fancy part number needed) for the Garmin High Density pins.
 
No need to be left out. You don't even have to join the secret society.

The color bands are part of the mil-spec and are on the good machined pins/sockets.

There is even no need to remember them though - or buy the secret decoder ring - since the three we use 99.9% of the time are sold by Stein so you can just use the pictures on his web site. :D

Tooling is also covered by Stein, one low cost tool for regular Dsub pins and a positioner for it (no fancy part number needed) for the Garmin High Density pins.

I bet we use 18 gage wire more than 0.1% of the time. Stein doesn't seem to have pins or positioners for those. I agree though, for MOST wiring, what he has is quite helpful.
 
No need to be left out. You don't even have to join the secret society.

The color bands are part of the mil-spec and are on the good machined pins/sockets.

There is even no need to remember them though - or buy the secret decoder ring - since the three we use 99.9% of the time are sold by Stein so you can just use the pictures on his web site. :D

Tooling is also covered by Stein, one low cost tool for regular Dsub pins and a positioner for it (no fancy part number needed) for the Garmin High Density pins.

And just to illustrate my bewilderment, note that Stein shows pictures of the data plates for the various positioners that he supplies to go with the DMC AFM8 crimper. But the Dsub contacts have M-numbers that do not appear on those data plates. So how does one know that that is the correct positioner for that contact, other than because Stein says so?
 
I bet we use 18 gage wire more than 0.1% of the time. Stein doesn't seem to have pins or positioners for those. I agree though, for MOST wiring, what he has is quite helpful.

Try buying Dsub pins for 18g. They seem to only come from Garmin and in very low quantities and high $$$.

Stick to 20g max for Dsub connectors. :)
 
And just to illustrate my bewilderment, note that Stein shows pictures of the data plates for the various positioners that he supplies to go with the DMC AFM8 crimper. But the Dsub contacts have M-numbers that do not appear on those data plates. So how does one know that that is the correct positioner for that contact, other than because Stein says so?

The fancy positioners come into play when you want to crimp other connectors than Dsubs.

Since this thread is for Dsub connectors only, this relatively low cost tool will do the job for one or two RVs...

https://www.steinair.com/product/4-way-indent-crimper/

41h%2BAPh0F7L.jpg


No need for tool envy over the multi-connector mil-spac crimpers. :)
 
I wanted to use crimps, I really did. I can see how fast it is, how nice to be able to quickly remove the pins to reposition, or to pass the harness through a bulkhead and then re-assemble in the connector. I even had available to borrow from work the expensive crimping tool and an assortment of positoners.

Absent any mentoring from an experienced avionics technician, I confess I could not sort out the bewildering miriad of specifications for what positioner to use with what crimper for what pins. I had no confidence that I could produce quality crimps when I couldn't even sort out which combination of the tools I was supposed to use. Not every avionics device was very clear at all about which tools to use. ( I have to say Garmin does a pretty good job trying to help out with this). I used to say to my self that if a high-school graduate that joins the Air Force and becomes an avionics technician can figure this stuff out, why can't a PhD in Aerodynamics that has done all kinds of sophisticated instrumentation installation for wind tunnel testing figure this out?

So, in the end, I soldered everything. Having heard all the hangar tales, true or not, I was careful to have good strain relief clamping on the backshell of each connector. And yeah, in a few places, forced to apply heat for a long time, some of the plastic bodies of the connectors show a little bit of heat distress. Always tested good. Everything works, and continues to work fine after 500 hrs.

But I really wish I had someone to sit down and say, "use this positioner in this tool with these pins" and I would have crimped everything. And if/when I redo my panel, I will scream for help here, and maybe someone can tell me what tools to use.

Oh, you PhD?s can make things so difficult. You were just working for the wrong center, in the wrong program. We got trained on this stuff in order to properly do In-Flight Maintenance (and to understand what we were asking our ?meat servos? to do....). Good multi-day class in the labs at JSC. Fortunately, someone wrote this all down in a guide you can find online:

https://workmanship.nasa.gov/lib/insp/2 books/frameset.html

I have re-pinned so many connectors as I do different avionics things to my airplanes, I shudder to think what it would be like to have to de-solder and then resolder all the time. Separate pins, sockets, and connector bodies are your friends!

Paul
 
Nice link Paul...thanks.I'm starting to believe that the solder vs. crimp threads should probably be moved to the never ending debates section!:D
 
Nice link Paul...thanks.I'm starting to believe that the solder vs. crimp threads should probably be moved to the never ending debates section!:D

:D

That was my first thought when I saw the title of the thread! But I resonated with it because of my troubles.
 
The fancy positioners come into play when you want to crimp other connectors than Dsubs.

Since this thread is for Dsub connectors only, this relatively low cost tool will do the job for one or two RVs...

https://www.steinair.com/product/4-way-indent-crimper/

41h%2BAPh0F7L.jpg


No need for tool envy over the multi-connector mil-spac crimpers. :)

I mostly agree Gil, except that the "real" tools have different crimp settings for different gage wire. The cheaper tool just gives one crimp depth, which may be ok on average, but not as good as the proper crimp pressure set for each gage.

So, accept for a moment that I have the expensive tool already (borrowed) and I just want to find which positioner in the bag of assorted positioners is the right one for my pins. The MS number for the pins do not appear on the data plates of any of the positioners, including the ones that Stein says are the right ones. So......I don't know.

Maybe the link that Paul posted will help.

And, good advise on sticking to 20 AWG. Although, most things have a DC power in and a ground that both would like to be a little heavier. Several of my avionics boxes call for it, including the Garmin GDL-82. Yes, the Garmin pins for 18 AWG are SUPER pricey. :eek:
 
Heck, if splitting hairs, Rob, one is a round pin, the other is a square socket.
(Hmmm sounds vaguely like my life story... LoL)

More hair splitting. It is a socket as you say, but it is made for Dsub connectors and mates with round pins.
 
Oh, you PhD?s can make things so difficult. You were just working for the wrong center, in the wrong program. We got trained on this stuff in order to properly do In-Flight Maintenance (and to understand what we were asking our ?meat servos? to do....). Good multi-day class in the labs at JSC. Fortunately, someone wrote this all down in a guide you can find online:

https://workmanship.nasa.gov/lib/insp/2 books/frameset.html

I have re-pinned so many connectors as I do different avionics things to my airplanes, I shudder to think what it would be like to have to de-solder and then resolder all the time. Separate pins, sockets, and connector bodies are your friends!

Paul

Like this post
 
I?ve had to trace wiring issues that turned out to be broken wire at solder joint. Now crimping D Subs with the CORRECT crimp tool. It must be a d-sub crimper. Spend the dough for the right tool. Steinaire has ?em.

Actually this goes for any task in building an RV. Use the right tool for the job.
 
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