0. Introduction
This is the first article of a series dedicated to SMT PCB development. In this one, I’ll talk about technique, tips and tricks to hand-solder SMT components, like SOIC, SOT-23, … up to smaller ones like SDE06A and RWL0009A.
1. Right tools for the job
The right tools enable us to solder better and wasting less time. Those are the tools I always recommend:
- a good solderer, better with a thin tip;
- a good-quality soldering flux;
Solder flux
- soldering wire (better if lead-free for safety reasons);
- copper wick for desoldering;
Optionals:

Antistatic tweezers
- heat gun for small parts removal;
- antistatic tweezers (required if using some fragile components);
- antistatic bracelet (also required for fragile components);
2. Good amount of flux and temperature
The two main points in SMT soldering are the amount of soldering flux and the temperature. An inadequate amount of flux will make the soldering difficult (in some cases impossible) and for this reason it’s a good idea to manually add it instead of using only the flux already inside the soldering wire. In addition to that, a too low temperature will take too much time to solder the components, with the risk of damaging them because of heat, and, on the other side, a too high one will just melt the plastic package as soon as we near the solder tip to the component. For this reason, it’s very important to always check the rated temperature of the component. (EX ADUM1250)
3. Soldering
3.1 Aligning the component

The small LMR62421X IC

The IC correctly placed
3.2 Applying the flux

Applying the flux
3.3 Soldering

The soldering stage

The final result

The result after cleaning process

3.4 Cleaning

Cleaning with brush and isopropryl alcohol
4. Final consideration
I hope this article would be useful to some of you out there. If you need some explanations, write me a message or a email and I’ll be glad to answer.
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