I am doing a hobby project where I am weaving stranded wire through vias on the PCB. There is a matching copper trace and solder mask under the stranded wire. The stranded wire is soldered onto the exposed copper trace. I do this to allow high amperage on the board which is only 1 oz copper weight. (Can't use another copper weight because of the PCB manufactorer)
I will also be adding conformal coating to this board, so then the question becomes:
Which type of flux should I be using?
Because flux residue should be cleaned when adding conformal coating, I was first considering a water soluble flux. But the data sheet says that stranded wire should not be used, which makes sense: Flux residue could be trapped inside the stranded wire.
So now I am considering to use a no-clean flux instead, because this flux residue should be OK to leave inside the stranded wire. It still needs to be cleaned on the surface however, to allow the conformal coating to bind. The downside is that cleanining it will be harder and nastier than a water soluble one.
What is my best option in this case?