Your recommended techniques for de-soldering?

@andrewb, so with Kester 63/37 solder, cleaning the flux off is optional?

Technically yes, if it's Kester 44. But it's unsightly, and gets uglier as the board ages, because the flux will turn from yellow to brown.

Because I just like boards to look nice, I usually remove most if not all old flux from boards I restore, many having prior work and flux that is decades old. I have never found a board to be damaged from any of these flux residues.

Also, see the datasheet for Kester 44:


1743116240680.png


The only time I have seen 'damage' is when I left Kester 331 (water wash/organic) flux for about a year on a Quantum board I was assembling. When I eventually washed it off, the joints and PCB were hazy where the flux had been, like it had etched the surface very lightly. But even then it was very slight, and didn't affect operation of the board at all. It was more cosmetic if anything. But if you'd left it for 40 years, it might be different.
 
Technically yes, if it's Kester 44. But it's unsightly, and gets uglier as the board ages, because the flux will turn from yellow to brown.

Because I just like boards to look nice, I usually remove most if not all old flux from boards I restore, many having prior work and flux that is decades old. I have never found a board to be damaged from any of these flux residues.

Also, see the datasheet for Kester 44:


View attachment 809124


The only time I have seen 'damage' is when I left Kester 331 (water wash/organic) flux for about a year on a Quantum board I was assembling. When I eventually washed it off, the joints and PCB were hazy where the flux had been, like it had etched the surface very lightly. But even then it was very slight, and didn't affect operation of the board at all. It was more cosmetic if anything. But if you'd left it for 40 years, it might be different.
Thanks, Andrew. Yes, it's Kester 44. So the flux really does matter and I should be good.
 
Thanks, Andrew. Yes, it's Kester 44. So the flux really does matter and I should be good.


You can google 'RA vs RMA flux' to find more on this topic. But yes, there are different kinds of flux. Here's one quick page about it, but there are more:

 
Well, let's see what the hype is all about.
Also, take a look below for another very useful tool for the FR tool…


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Solder-pull-it requires two hands, while the FR301 allows you to add some solder just before you pull its trigger to help with removal
Ground planes requires more heat for longer..
Solder removes more easily when sufficient heat is transferred to the (c/s)component side, from its (s/s) solder side.
although small stand alone pads need respect, please don't rest the tip of the FR301 onto the stand alone pad.
Also , Move the tip slightly upon sucking , Move opposite the lead thicknesses direction, while the FR-301 tip is inserted into the lead being removed, it you have
lead protrusion, meaning its lead is long enough. if no lead protrusion then make sure to add enough solder when sucking , make life easier ..
With Me ,,no clean flux still needs to be cleaned & any flux will clog the cotton filter inside the FR301,, its a preference...
 
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