Page 81 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

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66 Automobile mechanical and electrical systems

Figure 1.93 Soldering an electronic circuit

As a fi nal point in relation to adhesives, the importance of choosing the correct
type for the job in hand must be stressed. For example, an adhesive designed to
bond plastic will not work when joining rubber to metal. And don’t forget, if the
surfaces to be joined are not clean you will make a very good job of bonding dirt
to dirt instead of what you intended!

1.6.10 Soldering

Soft soldering is a process used to join materials such as steel, brass, tin
or copper. It involves melting a mixture of lead and tin to act as the bond.
A common example of a soldered joint is the electrical connection between the
stator and diode pack in an alternator. Figure 1.93 shows this process using the

most common heat source, which is an electric soldering iron.
The process of soldering is as follows:

1 Prepare the surfaces to be joined by cleaning and using emery cloth or wire
wool as appropriate.
2 Add a fl ux to prevent the surfaces becoming dirty with oxide when heated, or
use a solder with a fl ux core.
3 Apply heat to the joint and add solder so it runs into the joint.
4 Complete the process as quickly as possible to prevent heat damage.
5 Use a heat sink if necessary.

Soldering, in common with many other things, is easy after some practice; take
time to do this in your workshop. Note that some materials such as aluminium
cannot be soldered by ordinary methods.

1.6.11 Brazing

Brazing is a similar process to soldering except a higher temperature is needed
and different fi ller is used. The materials to be joined are heated to red heat and
the fi ller rod (bronze brass or similar), after being dipped in fl ux, is applied to the
joint. The heat from the materials is enough to melt the rod and it fl ows into the
gap making a good, strong, but slightly fl exible, joint. Dissimilar metals such as