Soldering & rework basics for board repair

Good rework is mostly heat control and flux.

• Iron temperature: ~320–350°C for leaded solder, ~350–380°C for lead-free. Hotter isn't better — it lifts pads.
• Flux is your friend. Fresh flux makes solder flow, prevents bridges and protects pads. Clean residue off afterwards with IPA.
• SMD work: use hot air (280–330°C) with the right nozzle, pre-heat the board where you can, and shield nearby plastics.
• Don't rip pads. If a joint won't release, add fresh solder to re-flow it rather than pulling on a cold joint.