- Here's a handy little list of things to prep before soldering on any small electronics board:
- You MUST have a temperature controlled iron. Never use an iron in excess of 350C/700F, as this will lift your traces and oxidize your tip.
- Avoid using wet sponges to clean your iron tip, this will shock and oxidize it. Use a wire brass sponge to prolong tip life.
- ALWAYS tin your tip before and after use!
- Always use rosin-based no-clean flux. Although you can use it in paste form, liquid is recommended for small jobs.
- NEVER USE CORROSIVE FLUXES!! Avoid using flux made with zinc chloride or ammonium chloride. These will eventually damage your board and iron. Only use Rosin-based flux.
- Always clean your board before and after soldering. You can use a mild solvent such as Isopropyl alcohol 96% or higher and scrub with a toothbrush or cotton swabs.
- Solder with flux or multicore solder with flux is recommended with a mix of 63/37 Sn/Pb. You can use lead-free solder, but remember it may be more difficult to handle.
A note about solder wire:
There are two main alloy mixes: 63/37 and 60/40. Is just a difference of percentage of lead & tin. 63/37 is eutectic, which means that it has a single point in temperature where it goes from a solid to liquid and vice-versa. 60/40 has a "plastic" state where it has some viscosity and then becomes a liquid. The opposite is also true when it cools down. The issue with that plastic state is that it can cause "cold solder" joints where you get cracks. 63/37 resolves that issue since it instantly becomes a solid and has no chance of cracking during the transition.