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Old December 26th 03, 02:50 AM
Tracy Fort
 
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On Thu, 25 Dec 2003 23:56:36 GMT, "Michael A. Terrell"
wrote:

Richard wrote:

From your experience, who's solder braid is the best? I want to desolder
some components and I want the braid to soak up the solder "At the drop of a
hat".


I use copper braid dipped in liquid rosin flux (RMA). One tip is to
live about 1/16" of braid with the solder in it when you clip it off.
Then put that part against the joint before applying heat. It can will
conduct heat to the old joint faster, and do less damage. The method is
called "Wet wicking" Keep in mind that wave soldered boards were done
with 80/20 solder so it would cool before leads had a chance to move.
So, you may need to clean the surface of the old solder before removing
it. Apply a thin bead of RMA flux along a row of pins. Put a small
amount of solder on the tip if the iron, and run it down the row to melt
oxidized solder off the surface. Then use the solder wick to remove the
solder. Before I was laid off, I routinely worked with 288 pin surface
mount parts and had to be very careful about lifting pads on $8,000
boards.

After a hole is clear of solder let it cool for a second or two, then
touch the tip of the lead and see if it is free. If it is stuck, let the
lead adsorb heat from the iron till it breaks free of the plated through
hole. Let it go and see that it doesn't stick again. With a little
practice you can do a row ow pins very quickly without damaging the
board. A good soldering iron is a must, and for modern ESD sensitive
parts you need a grounded soldering iron, along with an ES mat and wrist
strap.

If you start doing a lot of through hole work, invest in a vacuum
desoldering station.


Why didn't you just use a Pace station? It seems to me to be rather
risky to use solder wick on surface mount stuff especially with ESD
issues. We are never allowed to use solder wick at work. That said
some of the boards that we do are in excess of 200,000 dollars and are
irreplaceable. These boards are sometimes 8 levels deep and you have
to repair traces that are in the middle of the board. Paces stations
work really well for removing large smd's quickly. Then all you have
to do is run the vacuum over the pads to clean them up.

Tracy