A Lecture on Soldering By The Soldering Craftsman 1-9

Basic soldering steps

① Make the iron head contact the mother metal for heating
② When the temperature is reckoned high enough, feed the wire solder.
③ The amount of tin solder should be controlled and when it is reckoned enough, stop feeding the wire solder any more.
④ When you are sure the fused tin begins to join the two parts, remove the iron head.

The so-called “shadow soldering” is only a description that my soldering tutor made casually, which, I’m afraid, cannot be found in dictionaries. As a matter of fact, this term is only used to simplify the soldering steps and make the operation explained in a more vivid way. The four-step operation procedure is easy to remember for any one. There is no need to have power on when in training, and even a ballpoint pen can be used as a mimic soldering iron in training. Please have a try.

The so-called “shadow soldering” is only a description that my soldering tutor made casually, which, I’m afraid, cannot be found in dictionaries. As a matter of fact, this term is only used to simplify the soldering steps and make the operation explained in a more vivid way. The four-step operation procedure is easy to remember for any one. There is no need to have power on when in training, and even a ballpoint pen can be used as a mimic soldering iron in training. Please have a try.

① Make the iron head contact the mother metal

Those who do soldering simply by imitation are prone to misunderstand the job, because they believe the iron head and wire solder should contact the mother metal simultaneously and the wire solder is fused by directly contacting the iron head. But an experienced soldering craftsman would make the iron head contact the mother metal first and heat it to about 250℃ when either the mother metal is in small size or the capacity of the iron head is high enough. It looks as if the wire solder and the iron head were contacting the mother metal simultaneously, but as a matter of fact, it is not true.

② The wire solder will not be fed until the mother metal is thought to be heated sufficiently.

Step ① makes the mother metal heated sufficiently to about 250℃, and then the wire solder is fed. Of course, the temperature can not be seen. We can not say exactly that the temperature now is 250℃. But it may be figured out by taking into consideration the size of the mother metal (its thermal capacity) and the iron head thermal capacity. If the wire solder is fed earlier than it should be, it won’t fuse; while it is fed too late, the temperature will be too high and as a result, the electronic parts will be damaged, or the wire solder will be evaporated drastically. In this case, slight explosions may be detected by hearing the light cracking sounds. There may be some errors in temperature judgment due to the experience issue. Don’t worry about that as long as the error is within the tolerance.

③ The amount of tin solder should be controlled and when it is reckoned enough, stop feeding the wire solder.

Step ③ is for controlling the amount of tin solder. As was stated in 7.1 (Amount of tin solder), excessive use of tin solder is not encouraged. Long-time-feeding will make flux evaporated and cause cold soldering. So wire solder feeding should be quick with proper tin amount.

④ When you are sure the fused tin begins to join the two parts, remove the iron head.

Without this step, cold soldering may occur due to shortage of heat. The temperature with the mother metal and solder will both go down upon wire solder feeding. In this case, it is recommended to again create the optimum condition for building up the alloy layer between the metals at about 250℃. The iron head should not be removed until a fillet is formed.

It is recommended that during training, “Step 1”, “Step 2”, “Step”3” and “Step 4” be shouted as hints for trainees.