6. 3. Apply a flux using an acid brush
Flux is acid so do not use a regular brush.
Apply flux on the jointing part
7. 4. Heat round the jointing part
DO NOT Heat the jointing part!!!!
You heat only around the jointing part.
Otherwise, the wire does not get the certain temp to
merge flux and soldering core but only the core melt.
Once the flux starts bobbling, apply soldering core;
The core melts immediately.
DO NOT WAIT until flux gets burned
(will be brown color)