How to solder electronic components

Table of contents:

How to solder electronic components
How to solder electronic components

Any hobbyist or professional in electronics should learn how to solder components into the holes in the circuit board. You can educate yourself about the equipment and skills you need to know how to solder electronic components properly.


Part 1 of 3: Obtain the necessary equipment

Solder Electronics Step 1

Step 1. Use a soldering iron with proper heat control

For soldering electronic components in a circuit board, the best soldering irons are the powerful, temperature-controlled irons that prevent electrostatic discharge. They will keep you soldering for hours and are suitable for more complex projects. For simpler projects, a basic soldering iron will do just fine.

  • Use a 25-watt stationary soldering iron for small projects and 100-watt for larger projects that contain more cables.
  • If possible, find yourself a variable temperature soldering iron, as this helps you avoid damaging the circuit board. You can control the temperature of the soldering iron tip to suit the job at hand.
Solder Electronics Step 2

Step 2. Use a suitable alloy solder wire

The alloy most often used in electronics consists of 60% tin and 40% lead, sometimes noted as 60/40. This alloy is recommended if you are new to soldering, although it can be a bit dangerous and requires good room ventilation, respiratory protection and a soldering iron with a pump.

  • The 60/40 solder can be bent at 183 ° C, however it does not melt until 188 ° C. If you don't have experience, then it can be difficult to work on it. You can try a 63/37 solder which melts at 183 ° C.
  • Alloys that do not contain lead are becoming increasingly popular. They require higher solder temperatures and do not liquefy as well as alloys with lead. However, they are safer and can be more effective. The 96.5% tin and 3.5% lead based alloy is the most efficient and will produce a solder that will offer less current resistance than any other tin based alloy.
  • You can buy leaded or unleaded alloys on the Internet or in specialty stores.
Solder Electronics Step 3

Step 3. If possible, try to find yarn that contains thinner

The thinner is an additive found in the alloy which facilitates welding by eliminating and preventing oxidation while improving the fluidity of the alloy. There are different kinds.

  • Some fluxes are commonly used, such as RMA, RA, and water soluble fluxes. The more active the flux, the more important it is that no flux is left after welding, as the chemical action continues and can damage or compromise the operation or equipment. Water soluble fluxes should especially be removed.
  • Rosin is generally used by hobbyists. After soldering, it leaves a brown, sticky residue that is not corrosive or conductive, but which you can clean with isopropanol if desired. There are different degrees of rosin, the one that is used the most is "lightly activated rosin".
  • These thinners leave a clear residue after soldering that is neither corrosive nor conductive.The thinner is designed to be left on the solder and the areas around it.
  • Water soluble thinners generally have a higher activity rate and leave a residue that can be washed off with water. This residue is corrosive and could damage the circuit board or components if you do not clean it right away.
Solder Electronics Step 4

Step 4. Obtain the necessary circuit boards and components

In most cases, electronic soldering only concerns components to be inserted into holes on printed circuits. Electronic components have tabs to pass through the hole in the printed circuit board before soldering them to the metal ring around the hole. The hole could be plated or not.

There are slightly different techniques for soldering other items like cables, but the principles of using the soldering iron and the soldering wire are the same

Solder Electronics Step 5

Step 5. Obtain a clamp to hold the components

Electronic components are generally small and you are going to need pliers or tweezers to hold them in place while you use the soldering iron and do the soldering. It can be a bit complex.

In general, an alligator-type clamp is the best solution for holding items in place while you solder them

Part 2 of 3: solder the components

Solder Electronics Step 6

Step 1. Prepare the components to be soldered

Choose the right component, carefully checking its type and value. If you solder resistors, check their color code. Bend the legs as necessary, being careful not to break the component or twist the legs to get them into the circuit.

Solder Electronics Step 7

Step 2. Be very careful and solder the components in the appropriate place

You should always weld in a well ventilated place, protecting your nose, mouth and eyes. Be sure to leave the iron in the air when it is on, even when not in use. Soldering irons can start fires easily by igniting your work bench.

You must always leave about twenty centimeters of space between your face and the electronic components or they could jump in your face. The solder could also splash

Step 3. Prepare the soldering iron

Melt a small amount of tin at the end of the soldering iron. This step improves the conduction of heat from the iron to the plate, which helps protect it from heat.

  • Carefully press the tip of the soldering iron (with a small amount of tin on it). The tip of the soldering iron should touch the hole and the ring.
  • The tip of the iron should not touch the rest of the non-metallic parts of the circuit board or any fiberglass that may be around. These areas could be damaged if you apply too much heat to them.

Step 4. Apply the soldering iron to the area between the hole and the ring

The thinner in the solder wire is only active for a maximum of one second after being deposited on the solder spot, because it is slowly consumed by heat. The hole and ring should be hot enough that the solder wire can melt, not the connection point. The alloy should stick to the ring and the hole by its surface tension. It is often said that the component is “wet”.

  • If the solder wire does not melt on the area, it is likely that you did not heat it enough or that the surface needs to be cleaned of any grease or dirt that may be there.
  • Be careful). The sandpaper will generally be too aggressive and the glass wool (less mechanically aggressive) will add small particles of conductive metal, which can cause short circuits or unwanted electrical behavior.

Step 5. Stop adding alloy as soon as the hole is full

As a general rule, you shouldn't need more than a drop or two of alloy for each hole, although this will vary by component. The indicated amount of alloy will be determined by several factors.

  • On plated circuit boards, you should stop putting alloy on once you can see a concave thread of metal around the component leg.
  • On unplated circuit boards, you should stop putting alloy on as soon as you see a flat thread forming.
  • Too much alloy could form a bubble with a convex shape while too little will form a concave seal.

Part 3 of 3: solder well

Solder Electronics Step 11

Step 1. Act quickly

Unfortunately, it's pretty easy to damage a component or the plate if you overheat them. However, in most cases you can protect the plate and component by acting quickly. Keep a finger on the circuit board near the solder point to make sure it doesn't get too hot.

  • Try to use soldering irons that are slightly less powerful than you think you need. Use a 30 watt soldering iron and practice soldering quickly to avoid applying too much heat.
  • If you are working on a two-sided circuit board, check both sides to make sure you have clean solders. A good solder will look shiny and take the shape of a cone. If she looks "icy" and pale, you've missed her.
Solder Electronics Step 12

Step 2. Consider using a heat sink for more sensitive components

Some components (eg diodes, transistors, etc.) are more susceptible to heat damage and require a small aluminum heat sink attached to their legs on the opposite side of the plate. You can buy these little aluminum heaters at most electronics stores.

Solder Electronics Step 13

Step 3. Learn to recognize welds where there is enough alloy

After a good application of the solder wire, the solder should be shiny and not faded. Observe the weld to see if you made it right. It should have melted and merge with the surface of the electronic component rather than covering it. This way, when the weld cools, it will form an alloy with the surface of the metal.

The solder should cover the surface of the component evenly, not so much that it forms a ball, but enough to cover the entire surface

Solder Electronics Step 14

Step 4. Keep your soldering iron clean

You could burn plasticizer, rosin that was in the wire, or pieces of plastic on the iron. These contaminants prevent the formation of a clean alloy between electronic components. This is not what you want because it increases the electrical resistance and reduces the mechanical strength of the weld. A clean soldering iron tip is shiny over its entire surface, without showing any burnt residue.

Clean the soldering iron between each solder you make. Use a damp sponge or iron wool to clean it well

Solder Electronics Step 15

Step 5. Be sure to let the solder cool completely before moving the components

Let cool only for five to ten seconds. Large components have more mass, so it takes more heat and time for the solder to cool.

If the components are too hot to handle, you can use extended forceps or a “3rd hand” also called X-tra Hands. It is a template that can be adjusted with precision

Solder Electronics Step 16

Step 6. Practice with recovery components

It is important to practice with components that you would otherwise have thrown away before you want to solder something more important. Scavenge old components from an old radio or trash-safe electronic device to get your hands on them.

No one is perfect, not even the professionals. Don't feel bad if you have to repeat a weld several times. This will prevent you from having problems that will waste your time later


  • The tip of the soldering iron tends to jam over time (if you use it often) due to the build-up of oxides that occurs between the copper tip and the iron handle. Plated tips usually don't have this kind of problem. If you don't remove the copper tip every now and then, it will get stuck on the soldering iron permanently! It is then good for the trash. Every 20 to 50 hours of use, when it is cold, you should remove the mouthpiece and rotate it back and forth and in circles so that the oxidized residue falls off, before putting it back on. You can now keep your soldering iron for many years to come.
  • Most soldering irons have a tip that you can remove. These bits have a limited lifespan and come in all shapes and sizes to suit many types of jobs.
  • Keep a pear or desolder (which will suck up molten metal) or a coil of desoldering braid (thin copper wire that absorbs molten solder) handy if the solder spills out, you need to desolder a component, or if you need to remove excess solder.


  • Solder wires, especially lead-based ones, contain dangerous elements. Wash your hands after soldering and be careful, as objects that contain solder wire should be thrown with the rest of the dangerous objects.
  • Soldering irons are very hot. Do not put the tip in contact with your skin. You should also always use a suitable stand to keep the tip of the iron in the air above your work surface.

Popular by topic