That looks like you covered the entire thing in solder.
daman... Did you cover the entire thing in solder?
Seriously now, I'm not complaining about your work, it must have been really meticulous to use such a small plug. So you used silver epoxy? By the way, next time try to clean the cover of the wire by passing the solder wire through it. I also assume the plug on the right is the old one, right?
The connector is covered with clear epoxy. It has lasted well for 3 years already. I don't know why you think it's covered in solder or silver epoxy???
Some headphone wires got a coating that won't burn away easily. It just causes the strands to heat up and then melts the insulation. Then you need to scratch away the coating just like I did. Some cables got a weaker coating on the strands that you can easily burn away with a blob of solder on the soldering iron.