Help! Help removing flux or damaged board??

[RHengelsberg]

I am currently building a drone and am in the process of soldering the escs on. The first 3 and a half escs soldered on with ease then when I tinned this pad, the solder was only sticking to the center of the pad. I then soldered the wire on thinking that it might be strong enough. When I soldered the wire on everything was melted fine, but when I released the wire it just popped off along with the solder that was on the board. I repeated this process 2-3 times. When I touch this area it is slightly sticky to the touch. It was more sticky but I put isopropyl alcohol on it. Before I put the alcohol on it there was a visible layer of what looked like flux. Is this just flux residue or a damaged board?

 

[Hai-Lee]

From what I can see it might a point where the environmental coating is thickest.
Environmental coating is something akin to a varnish used to protect electronics that are exposed to the environment.

I would be tempted to clean the pad with a slight abrasive to remove all contaminants or use a knife to scrape the rubbish off and tin the pad first.

After tinning I would clean the wire to be attached as the solder looks grainy. This could be an indication of either too much heat or too little used in the soldering.
After tinning the pad should have a shiny uniform covering layer of solder, as should the wire to be soldered.

Next heat the pad, place the wire onto the pad, and apply a little additional solder. When the solder one the pad, the wire, and the additional solder are all melted together remove the iron without moving the wire. When cooled the joint should be good!

Have fun!

 

[RHengelsberg]

Thanks a lot for the help. Is there any chance I could damage the pad by using a knife or other abrasive material on it?

 

[Hai-Lee]

Not really. Just scrape the surface very lightly. I often use a glass fitted eraser, (ink eraser?), to remove the coating and then something like metholated spirits on a cotton bud to remove the rubber residue.

You can damage the pad or the board with too much heat though, so be careful!

Have fun!

 

[RHengelsberg]

Alright, sounds good. Thanks for the help.