Bad Soldering Practice: Why you need to remove solder flux from your PCB?

RE: Bad Soldering Practice: Why you need to remove solder flux from your PCB?

embeddedguy — Sat, 18 Mar 2023 05:54:14 GMT

Very good write up. I am new to SMD soldering and did not even know how/where to start. Then, I asked some friend who is doing mobile repair work and he insisted me some solder liquid which unfortunately did not work for my use case. So now I have ordered solder paste online..

RE: Bad Soldering Practice: Why you need to remove solder flux from your PCB?

michaelkellett — Thu, 16 Mar 2023 18:07:30 GMT

Some of this article isn't very well alligned with current practice.

No clean fluxes are very widely used in commercial equipment (ie - pretty much everything).

No clean fluxes can be removed by water + detergent + ultrasonic processes.

The flux usually comes in solder paste - its part of what makes it paste rather than metal dust.

There are several different kinds of liquid flux - for hand working you need to use a LOT - and then clean after.

I agree about tap water.

And except for special purposes you should always use water based cleaning (with compatible fluxes) (think of the ozone layer and your bank ballance)

And dry the assembly as soon as its cleaned.

RE: Bad Soldering Practice: Why you need to remove solder flux from your PCB?

dougw — Thu, 16 Mar 2023 13:37:13 GMT

Excellent article. We have experienced exactly all of those problems with flux residue, and it is hard to clean it well enough to have no problems. You can clean it to the point where you cannot see it, and it still causes problems (that go away if you clean it even better). In our case it really shows up with low voltage signals in high impedance analog circuits where any leakage has a major influence on the signal voltage.