Sunday, November 15, 2009

How to Avoid Dry Solder Joints

If you have been making too many dry solder joints, then here are some tip on soldering. By the way, just in case you did not know, dry solder joints can create a potential fire hazard, add unnecessary noise in the circuit and add to instability of electronic circuits. Hence some quick and dirty tips:

1. Make sure that you are using the right soldering iron for the job. You need to have enough wattage to thoroughly heat the parts without burning them out. For example, while a 15 watt soldering iron is good enough for soldering tiny microprocessors on a printed circuit board (PCB), it would not work if you are planning to solder 10 AWG stranded wire speaker connection on a crossover network. For that you will need at least a 60 watt soldering iron. By the way, there are variable wattage soldering irons available too.

2. There are rosin core and acid core solder availble in the market. Rosin core solder are used for all electronic work. Don't ever use acid core solder for electronic work.

3. Flux is used to avoid oxidation of exposed copper during soldering of electronic circuits. I like to use liquid flux with a tiny brush. I have used flux paste too but my preference is still liquid flux.

4. It is a good idea to "tin" the tip of the soldering iron (unless you are using a nickle/chrome plated soldering tip). Tinning of parts is also a good idea. This avoids oxidation build-up and improve the quality of soldering by improving heat transfer.

5. Unless you are using a nickle/chrome plated soldering tip, you should file the tip of the soldering iron to remove oxidation build-up.

6. Heat the tips of the parts that you are trying to solder by quickly touching them with the tip of the soldering iron before applying the solder. Apply the solder, when all the parts are hot. The melted solder will flow evenly coating all the surfaces.

These tips will help you make a good electrical connection. All the best!