anyone ever see this before QAV 400

[38super]

Hi
I had previously posted a problem I was having with my QAV 400. (smoke from motor) I took the top plate off to get a look at the dirty plate. Found the soldering points looking pretty bad . On one of the pic you can see the copper exposed . I sent these pictures to people who built it (only one of 5 Multi rotors I had built the rest I did….. was not cheap)
My question is Is flux conductive at all? To me it looks like it's been over heating especially looking at the two main power leads . Almost looks like there burnt or is it just flux discolored. Other picture shows exposed copper where the insulator came off.
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[Chalagi]

Any thing that's wet would be conductive and flux is corrosive and that kinda looks to me like rust. I would just redo the connections and see what happens. Also you might put some hot glue on your connections to seal them from the elements.

 

[Electro 2]

Correct on corrosive. Keep in mind high quality hand-solder work requires the *removal* of any remaining flux after the joint has solidified. True of almost all MIL hand soldering specifications. The MIL specs reccomend the use of isopropanal which is not reactive with most plastics. I usually use hardware store grade lacquer thinner on a Q tip. This will dissolve many plastics, however, so one has to be careful not to use it in areas where there are plastic parts near the site. And yes, I have reworked many, many, Chinese sourced hobby devices, (FCs, ESCs, etc.), to clean off the flux.

 

[bruce365]

You can also use methylated spirits (alcohol) to clean off flux residue, its not dangerous and does not harm anything.
regards - bruce