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Subject: Re: [motm] Remedial soldering 101

From: "Richard Brewster" <pugix@...>
Date: 2002-12-09

Remedial soldering 101
Good chance there is a problem with the soldering iron.  First thing, make sure the tip is secure and not loose.  Next, change the tip.  Better yet, ditch the cheap iron and get a temperature-controlled unit.
 
Heating for 15 seconds is way too long.  Something is amiss.  Soldering tips (oops, a pun):
 
Always keep the tip clean and tinned.  The work should be tinned first (MOTM wires come pre-tinned).  Apply the tinned tip to the work.  Hold it so both work parts are touching the tip (braid and lug in this case).  Heat the work for a short time (1 - 3 seconds, depending on the size of the work and the heat of the tip) before applying solder, and then apply solder to the work - don't apply the solder to the tip.  You want the heated parts to melt the solder, not the tip.  This requires good contact between the tip and the work, and a tinned tip.  Flow just enough solder onto the work, then remove the heat.  Do not disturb the work until the solder cools and sets (typically 2 - 5 seconds).  The joint should appear smooth and shiny.  After doing this a few thousand times, you start getting the hang of it.  The same principles apply for any size of work, but the durations and tip temperature will vary.  It does require learning a feel for it.
 
If you need to redo a joint, sometimes it helps to remove the old solder with a solder wick braid before starting over.  That's an art in itself that I won't go into right now :).
 
-Richard Brewster
 
----- Original Message -----
From: Brousseau, Paul E (Paul)
To: motm@yahoogroups.com
Sent: Monday, December 09, 2002 2:32 PM
Subject: [motm] Remedial soldering 101

OK, either I have lost ALL my chops, or something's amiss.

I finally got a day to myself yesterday, and I took that time to construct the 830 mixer.  (Yes, it's been THAT long since I've been able to do much soldering-- I got it as a subscriber.)  Got all the way up to soldering the braided ends of the coaxial to the bevelled lug on the switchcrafts, but no matter how hard I tried, I could not get a good looking joint.  The solder just bubbles up around the joint, rather than really melding.  All my other joints (including the core of the coaxial) look good to decent.

It feels like I couldn't get the braided wire hot enough to meld with the solder.  At one point, though, one of the braids become brittle and snapped as I flexed it.  Surely this isn't very good.  I had my (cheap Radio Shack) soldering iron set to "high", which has consistantly worked in the past.

Any suggestions?  I've never changed the tip, but that hasn't seemed to give me any trouble before.  Perhaps the iron is failing?  Did something change with the coaxial?  Do I need to learn more patience and wait a significant amount of time (i.e., more than 15 seconds) before applying the solder to the braid?

Tonight it gets powered up to see just how badly it's turned out.  :(

Thanks for any suggestions!

--PBr


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