How To Solder

Understanding Solder Wire.

There are different types of solder for different jobs. There are usually two types of solder. The one type is made up of an alloy of 40% tin and 60% lead and the other one is 60% tin and 40% lead. The latter is usually preferred for electronics.

There has been a drive to eliminate the lead content in certain countries due to the toxicity of the lead. Lead has been known to be absorbed through the skin and inhaled by the fumes given off during the soldering process. This lead is usually replaced by either copper, silver, bismuth, antimony, indium, zinc, etc.

Solders used for electrical or electronics are resin cored and solders used for sheet metal plumbing are usually acid cored. Plumbers also use soldering bars which are acid free. One usually uses spirits of solder when soldering with these solder bars. Jewelers usually use borax acid for soldering jewlry.

A soldering paste, usually known in the trade as soldering flux, or resin flux is often used when doing electric or electronic soldering. However this is not always a necessity.

Applied to components before soldering some times to ensure a clean joint when soldering. Prevents oxidization when heating and helps to clean the joint.

Three basic rules for soldering.

1. Ensure that you have enough heat available to do the soldering. If the temperature is too low it causes crystallization of the solder which leads to a poor electrical connection.
2. Do not over heat. Overheating causes the solder to oxidize. This also leads to a poor electrical connection. In both cases these connections will deteriorate in time.
3. Ensure that the surfaces to be joined is clean and grease free. Dirty surfaces lead to what is commonly known as dry joints. This comes from the term known as wetting or tinning the joints before soldering. This means applying solder to both surfaces before joining. If the surface is dirty the solder will not bond properly, which leads to a dry joint. In other words it wont wet or stick to the dirty surface..

Soldering Irons.

There are numerous types of soldering irons out there. The professional irons for electrical  or electronic work are  usually temperature controlled. This is usually between 180 - 200 deg Celsius.
Powers ratings usually range anything from 15 watts to 500 watts. The 15 to 60 watts is usually used for electrical or electronic work. The heavy duty ones are usually used for heavy electrical wires or light metal sheet work. Extra heavy sheet metal soldering irons are usually flame heated.

This soldering iron is temperature controlled. Adjustment of the temperature is carried out by changing the tips. The tip has a magnet on the end which loses its magnetism after the predetermined temperature. Once the magnetism is lost the magnetic switch inside the soldering iron opens and the iron is switched off. As the iron cools the magnet regains magnetism and the switch is once again activated to reheat the iron.

How to solder electrical wires or electronic components.

1. Ensure that the soldering iron is up to temperature, and that both surfaces to be joined is clean and grease free.
2. Clean the tip of the soldering tip with a damp cotton cloth.
3. Apply a small amount of solder to the tip of the iron to ensure decent heat transfer to the job.
4. Heat up wire #1 with the iron. Hold the solder wire against the wire until the solder flows freely along the wire, covering the surface evenly.
5. Repeat the same procedure to wire#2 
6. Hold the two surfaces together and gently apply solder while heating with the soldering iron. Once the solder flows freely remove the soldering iron. Always hold the soldering iron against the job until its hot enough. Do not dab the iron against the job. If you hold the iron too long the solder will go dull on the joint. Stop the process, remove excess solder and repeat the process again. Never carry solder to the job on the soldering iron. By the time the solder reaches the job the oxidization process will have started. A decently soldered joint is always bright and shiny.

Desoldering wick used to absorb excess solder when unsoldering.

Solder Sucker used for sucking up excess solder when unsoldering components.