Solder, Or Not? Options

[NARP74]

Someone had tried an electric pump conversion in my car. The switch is wired but they never finished the job. The wires were the wrong length and I decided to fix them.

I remember reading an article about the space shuttle. They said it had no soldered wire connections anywhere, everything was crimped. Soldered connections were to a board with a connector, not wires. Fast forward many years and I saw an interview with a Porsche mechanic and he said Porsche spec is no soldered wire connections.

My first thought was to grab a soldering iron and use it to extend the wires. Am I being old school?

[914werke]

No. use crimps with the proper tool wherever possible

[Cairo94507]

I have soldered wires and shrink-wrapped them. So long as the wire is clean, you use a flux-solder and good heat, I do not see an issue. (IMG:style_emoticons/default/beerchug.gif)

[Root_Werks]

I typically crimp, yes, use a correct crimping tool.

Wonder why no soldering? Corrode over time?

[NARP74]

I think they said it made the wire too brittle. What's the point of stranded wire for flex when you add solder to make it solid. I would guess vibration would be an issue in a space shuttle.

[GregAmy]

I think they said it made the wire too brittle.

This. Same with aviation (well, general aviation, at least).

I always crimp, using the best set of ratcheting crimpers I could find. I built my Microsquirt engine harness with Deutsch connectors and crimping the terminals.

I will, however, use soldering when I join two wires inline with a "telegraph/lineman's splice" and heatshrink to support it as strain relief.

EDIT: I learned electric design and implementation many years ago from a guy that used to travel and give build seminars, Bob Nuckols of the Aeroelectric Connection. I have his book and attended a couple of his seminars and talks. What I learned from him has been incredibly valuable. Bob hasn't been around lately but I hear he's still kicking...

Anyway, the point of this is to link to this article about how to do soldered connections well (take some time to brwose through the whole web site). Here's his ending paragraph:

Dispelling a Myth
Some folks recommend a combination of soldering in
addition to crimped joints for reliability. Keep in mind that
the Boeings, Beeches, Pipers and even the lowly Cessnas
haven’t soldered a terminal on a wire in over 30 years.
People like AMP and Molex have carved an honorable
place for themselves in the aviation marketplace selling
termination systems that do not require solder to achieve
the highest levels of reliability. Please forget the solder.

http://www.aeroelectric.com/articles/terminal.pdf

[Superhawk996]

I would guess vibration would be an issue in a space shuttle.

Vibration is a huge issue in automobiles which is why all terminations are crimped (edit: in modern autos).

From the NASA workmanship pictorial guide

[Craigers17]

While I always crimp my connections, I have to admit that I learn stuff here daily. I appreciate all the wisdom on this site.

[JeffBowlsby]

Good points made above. Copper wire work hardens at the juncture where it becomes encased in solder, i.e. stress concentration and eventual breakage where either the wire or what it is attached to experiences vibration. In line, free hanging soldered attachments are not as subject to vibration-related stresses as when one side is fixed, and stress relief always helps.

Note that 914s have both soldered and crimped wire attachments (mostly crimped). Bullet terminals at the back-up light switch, 12-pin and 14-pin connector housings at the relay board, the 3 pins at the fuel tank connector housing, the 4 pins at the fresh air fan, etc - all are soldered attachments.

[windforfun]

IIRC BMW & MBZ cripmed & soldered. No cut strands.

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[930cabman]

I like solder and haven't seen one fail

I'll bet NASA has the crimped connections with the engineered stuff behind it. How many of us have the "proper" tools/connectors/ know how?

[Shivers]

I bought a new soldering iron and a ratcheting crimp tool for this car. What a difference from the manual crimper. Once crimped it is not coming off. Shoot even the crimp is a cool shape.