|10-07-2006, 04:56 PM||#11|
I am: Boolean21
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|10-07-2006, 09:34 PM||#12|
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I am: Earl A.
Join Date: Jun 2006
Location: Erin, Ontario
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Soldering and De-soldering
Hey MGF, thanks for the complement!
This is what I have learned from a career of soldering and desoldering electronic components:
SOLDERING and DESOLDERING:
The idea is to be like a mercenary: get in quick, do the job, and get out just as quickly. This means having the right sized iron for the job and having everything prepared (clean) before you start.
Cleanliness is next to godliness. When soldering, this means that the two (or more) surfaces being joined, the iron tip, and the solder itself (yes, solder does oxidize if it's been sitting around awhile, ask me to show you some that has) all have to be as clean as possible.
A word about soldering irons (well, two words): Tips oxidize. This means that you either have to clean or tighten the electrical/thermal connections from time to time for best soldering iron performance. The best example of this is a soldering gun that's slow to heat-up. Try tightening the two nuts that hold the tip on and note the results.
I have seen the odd person at Sid's using acid core solder or acid paste flux to clean the two materials being joined during the soldering process. While fine for your pipes at home, this is a big no-no in the electronics world. Why? The conductors are either so thin or small that the acid can potentially eat them away completely.
Some tricks to prep conductors for soldering:
1. For copper: Vinegar then water rinse then dry thouroughly. This works great on battery bars.
2. Pencil eraser on printed circuit board traces.
3. Try fine emery cloth or a scalple blade on fanned out conductors in stranded wire. Clean thoroughly before soldering to get all the bits of grit out.
"Tin" (Pre-solder) the two components before you try to solder them together. The idea is to get a thin coat of solder on both pieces. Wipe each piece with a damp rag to get the excess off if you use too much solder.
The trick with soldering is evenly heating both pieces to be joined. You can adjust the heating bias between the two surfaces by letting more of the tip area rest on the part with the greater thermal mass. Also, solder always runs ("wicks") to the hottest area.
Finished joints have a higher melting temperature because the solder has alloyed with the base materials (usually copper) in the components that were joined. I sometimes add a bit of new solder to an old joint I am trying to desolder to get the melting process started. I'm not sure, but I think I'm diluting the percentage of base metal in the solder 'puddle" (thus lowering its melting point) when I do this.
Hope this helps,
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