flux in soldering

The main focus of this Tutorial is to make you learn how to solder properly and what tools are used in Hand Soldering process.

Hand Soldering is a process to used repair, Modify or conducting joints in a printed circuit board (PCB) assembly process. In hand soldering hot soldering iron tip heats the solder and it flows insides the metallic surfaces to form a solid joint.

Mainly hand soldering is recommended in prototyping, Installation, and repairing of PWBs in surface mount technology. For best joints some sort of soldering techniques needs to followed.

Tools and Materials

Soldering is a process in which two or more metal items are joined together to make a electrically conductive strong bond between two surfaces by by melting and then flowing.

How to Solder – Hand Soldering and PCBA Rework Tutorial
How to Solder – Hand Soldering and PCBA Rework

Here I will explain how to solder and what are the mainsoldering tools and accessories are required to make a quaity solder joints.

The quality of hand soldering mainly depending on soldering iron tip geometry, Selection of Flex, and instruction followed. Handholding is not so easy to work as normal people think.


It is required to adopt some sort of tools and techniques to get minimum scrap rate, higher productivity and better PCBA quality of rework consistency.

For more information and technical specs further details on soldering check out the wikipedia article.

1. Soldering iron
To do a soldering you need a good quality soldering iron or temperature controlled soldering station.Soldering iron good heat source that heats up and cools down very quickly and to maintain a constant temperature.

Soldering irons soldering components recmonded as Low wattage (15-40 watt) soldering irons but while more powerful circuit boards (60-140 watt) soldering irons can we considered.

The soldering iron there are some worldwide leaders in manufacturing and supply of soldering tools like Hakko, Weller etc. for more details and buying guide for Best Soldering Irons for 2020.

2. Solder wire
Solder wire is the main consumable material used in hand soldering.it comes in various thickness with leaded and lead-free versions. You use thin solder wires for nornal electronic component soldering and thick when needs to solder large solder sourfaces.

For more information and technical specs further details on solder allows check out the wikipedia article.I use normally solder around .025″ wire in daily soldering jobs.

3. Soldering iron tips
Soldering irons come with different types tip to do different soldering jobs.It is very important to choose the size and geometric shape of the solder Iron tip in hand soldering . A Tip must be selected in this way that it will fit the size of the component on the board.

How to Solder – Hand Soldering  and PCBA Rework Tutorial 1
How to solder : Selection of right sldering tips

4. Other material needed for Hand Soldering
Apart from above soldering tools there are few other tools are also used to make a solid quaity soldering joints.

A list of other tools are Soldering iron holder, cleaning sponge, Exhaust fan, Tools to work with wires like wire cutters, needle nose pliers, a wire stripper etc., Safety goggles ..

Getting Ready for Soldering

How to Solder – Hand Soldering  and PCBA Rework Tutorial 3

Once you are ready with all the tools and soldering material, you are ready to start oldering iron and let it heat up while prepping my materials.

First things is that Use the lowest possible soldering temperature (when using tin/lead solder not higher than 360°С and when using lead-free solder from 400°С to 425°С).

How to Solder – Step By Step

  • Use the lowest possible soldering temperature (when using tin/lead solder not higher than 360°С and when using lead-free solder from 400°С to 425°С).
  • Contact both terminals with heated soldering tip and feed solder wire into the joints. Hold the tip until the melted solder flowed into the joints.
  • Clean the soldering iron tip during its use with special tools (damp sponge, steel brush).
  • Do not apply too much force when soldering (do not apply pressure on a board).
  • The sponge must be damp, not wet. When pressing on a sponge water must not pour around it.
  • Turn off the soldering iron if not in use for 5 minutes or longer.
  • If you finish working with the soldering iron tip, clean it and tin it (apply the coating of solder to the tip).
  • Change a tip properly only by using a rubber pad intended for that purpose.

Defects due to incorrect use of soldering iron tips

Metal plating tip of soldering iron wears out over the time. Plating life of soldering iron tip on a type of soldering application, types of flux and solder paste used and the soldering skills of the operator.

Generally, the manufacturer does not give any guaranty of soldering iron tips. Usage of defective soldering Iron tips results below soldering defects.

  • Cracks: – Due to Excessive pressure is applied with a tip to a contact area resulting in a bend of the tip.it will cause the cracks in the tip coating. To avoid this problem, select the tip that best suit your work.
  • Non-wetting: – Oxidation of tip coating causes heat conductivity reduces due to formed oxides that will not allow proper wetting of molten solder paste. The best remedy to avoid such consequences frequently clean solder tip with a damp sponge, Use the lowest possible temperature, not recommends using active solder flux.
  • Corrosion: –Usage of Active solder paste at high temperature (>450 °C) the coating of the tip can be possible to damage partially or completely. For remedy use less active flux, use clean and damp sponges, and use solder that has RMA flux type.

Further reading

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