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  #21  
Old 06-13-2018, 06:31 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
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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.
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Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 422 hrs. on the Hobbs,
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  #22  
Old 06-13-2018, 06:34 PM
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FasGlas FasGlas is offline
 
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Those aren't crimp connectors, those are solder connectors. And heat shrink is a must when using this type.
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  #23  
Old 06-13-2018, 06:46 PM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by FasGlas View Post
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.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 422 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


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  #24  
Old 06-13-2018, 08:25 PM
rv7charlie rv7charlie is offline
 
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Quote:
Originally Posted by FasGlas View Post
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
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  #25  
Old 06-13-2018, 11:19 PM
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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)
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  #26  
Old 06-13-2018, 11:57 PM
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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.
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  #27  
Old 06-14-2018, 12:02 AM
scsmith scsmith is offline
 
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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.
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  #28  
Old 06-14-2018, 12:13 AM
scsmith scsmith is offline
 
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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.
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RV-8 N825RV
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WW 200RV
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also LS-6-15/18 sailplane
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  #29  
Old 06-14-2018, 12:44 AM
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az_gila az_gila is offline
 
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Quote:
Originally Posted by scsmith View Post
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.

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.
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  #30  
Old 06-14-2018, 02:23 AM
scsmith scsmith is offline
 
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Quote:
Originally Posted by az_gila View Post
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.

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.
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RV-8 N825RV
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WW 200RV
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Hobbs 500 in 8-3/4 years
also LS-6-15/18 sailplane
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