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Tony Miklos[_2_]

On 11/30/2010 1:00 AM, wrote:
On Tue, 30 Nov 2010 00:10:25 -0500, Tony Miklos
wrote:

On 11/29/2010 4:13 PM, HeyBub wrote:
Smitty Two wrote:

As others have said, the solder won't stick to crud. Follow these
steps for your abused iron.

1. Using a file or sandpaper, abrade off the crap from the tip of
your iron until the tip is shiny base metal (either copper or steel).

2. Plug in the iron and, when it gets hot, cover the tip with solder.

3. Periodically during your soldering project, drag your iron's tip
over a damp sponge.

4. When the iron's tip turns black and can't be returned to shiny
via the sponge business, repeat steps 1& 2.

5. You are correct when you twist the wires together. Soldering is an
ELECTRICAL connection, not a mechanical one. Depending on solder to
hold two items together is ultimately futile.

Nuts. OP, do not sand the tip. Throw it away and buy new. The base
metal of the tip will not tin with solder, only the plating will.
Once the plating is shot, it's shot.

Oh. Didn't know that. I suppose the cheap, disposable tips are merely plated
(maybe even just painted in bright colors) - the ones I use are solid
copper.

Solder is a mechanical *and* electrical connection. Twisting is a
great idea, but solder is used all damn day long as the only
mechanical bond between items.

Agreed solder IS a mechanical connection; a ****-poor mechanical connection
at that. Lay two wires side by side and solder them together. Then pull them
apart. Next tie the two wires together in a knot, solder them, and pull them
apart. If you can.

There's a HUGE difference between a soldered mechanical connection and the
mechanical connection of a solder joint.

A properly soldered joint doesn't not need a mechanical connection, like
twisting the wires together, in order to make a permanent electrical
connection. Matter of fact, NASA prohibits any such joint. They
prohibit it because if repairs are needed it is too difficult to take apart.

You are using a double negative so appear to be disagreeing with
tourself - but regardless, nasa notwitstanding (if it is true)
acceptable standards for aircraft repair ( I believe it is AC 43.13)
specifies joints must be mechanically secure before soldering, but
also (quite severely) limits where soldering is acceptable in aircraft
wiring. Solder wicking back a stranded wire hardens the wire and makes
a stress point where that hardening stops - a failure waiting to
happen when exposed to vibration.

Ah, a typo. Read it as a single negative and you will understand what I
mean. Another reason solder joints shouldn't be mechanically secure
before soldering is because that practice can hide poor solder joints.
It may be a cold solder joint but it doesn't show up easy as if it would
without a separate mechanical connection.

As far as solder wicking up wire, yes I agree the wicking and vibration
is a very bad combo. As far as NASA, I believe that was mostly applied
to components on circuit boards.