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Date: Tue, 10 Oct 2006 21:40:16 -0500
From: Charlie England <ceengland@bellsouth.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: solder vs. crimp; was: Re: Latest EC2 updates, Installation notes
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Joe Ewen wrote:

> I second Al opinion on not using soldered Dsub connectors.  In my 
> opinion crimped Dsub connectors are more professional and potentially 
> reliable.  Soldered connections are more prone to corrosion, cold 
> solder joints, crystallizing and breakage from vibration.  I am not 
> saying I do not have any solder joints in my airplane, but there are 
> none anywhere in the engine controller circuit.  If you are looking 
> for a source for milled pins - Steinair.com, $25 /c for pins and 
> sockets.  Crimped (milled) pins and sockets are much easier and IMO 
> result in a more professional installation.


snipped

I must respectfully offer a somewhat modified view.

In general, crimped connectors are only reliable if done with very high 
quality crimpers, costing many 10's to hundreds of dollars. In a 
production environment, big bucks for a crimper means any klutz who can 
squeeze can be very productive.

Soldered joints are prone to corrosion only if corrosive flux is used. 
Improperly crimped pins can have corrosion within the joint, just like a 
riveted or bolted structural joint. Crystallizing is a product of 
improper technique, not the soldering process itself. Breakage from 
vibration is an issue with either technique; the stress riser on a 
crimped joint is much sharper than a soldered joint. Proper support just 
outside the joint is the remedy, whichever process is chosen.

Milled pins are certainly better than the rolled sheet metal pins, but 
with proper technique, they can be soldered with relatively inexpensive 
equipment.

FWIW,

Charlie