How To Use a Soldering Iron? Step By Step Tutorial 2021
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Welding is indeed a very useful skill. Learning welding skills is also very interesting! This is true. You will know later. If you know the soldering skills, you can almost do a lot of work on soldering electronic components, which is really cool!
The electric soldering iron is one of the most commonly used soldering tools.
There is a lot of information on how to use a soldering iron on the Internet, but this time we choose to introduce you to how to use a soldering iron more interestingly.
Combined with the hand-drawn schematic diagram, I believe it can make this learning process easier and more interesting.
Before formally introducing how to use a soldering iron, let’s first understand the tools used in soldering and the simple soldering principles and methods.
Basic Knowledge And Preparation Of Soldering With Electric Soldering Iron
The picture above is a typical electric soldering iron tool, and its tip has enough heat to melt the metal welding material. Its temperature range is about 180~500℃/356~932℉!
Safety Tip #1/3: If you accidentally touch the end of the soldering iron, please let go! To avoid injury. Also, you’d better prepare a welding goggle.
The coil in the picture is soldering material, generally made of tin metal or lead metal.
The hollow tube of the welding material marked by the arrow is filled with rosin (this material is similar to the substance that increases the violin bow’s viscosity).
We use an electric soldering iron to melt the soldering material to connect the circuit components. When the welding material is heated, its temperature rises, the rosin inside immediately melts, and the welding material’s metal also melts.
When the rosin flows to the location you want to weld, clean the metal to complete a good weld.
The best electronic soldering material comprises rosin as the core, 60% tin and 40% lead. Among them, rosin is also used as a flux.
There are some other types of soldering materials, such as lead-free solder, but they contain other toxic chemicals inside, and it is not very convenient to use with an electric soldering iron.
It will also quickly erode the head of your soldering iron. If you can only find this lead-free solder, that’s okay, but please don’t breathe the bad fumes from it.
If you don’t wash your hands after soldering, the lead metal in the soldering material may enter your body, and if it accumulates for a long time, it may remain in your brain.
If too much lead metal accumulates in the human body, you may get sick at that time and cause a sadder story…
To prevent such a story from happening, please remember to wash your hands in time after completing the welding work.
Safety Tip #2/3: Lead metal is toxic. When you are soldering, your skin will inevitably come into contact with lead, so after you finish soldering, please wash your hands.
Electronic circuits are made up of electronic components connected.
To make the circuit work correctly, we need to connect everything connected correctly and don’t connect everything that shouldn’t be connected.
The printed circuit board makes soldering easy because it has many pads for electronic components.
If you look closely at the printed circuit board, you will see the lines connecting the pads, and these lines become lines.
All electronic components have exposed wire ends, and all wire ends, regardless of their shape, are called leads (LEADS), and they are used as part of the guiding element.
Most of the pads will have a hole in the middle, and the circuit connection is through the leads and soldering.
If you put the leads of all components into the pads belonging to each component, and you have placed them in the correct direction and successfully soldered (please note that some components may be placed in the wrong direction).
Then, the circuit can operate normally! This is because the circuit board connects the connected components correctly.
Take The Welding Of The Simplest Resistance Element As An Example
So how to use a soldering iron? I believe you can’t wait to know!
Next, let us do the first welding together!
Let’s start with a resistor. The resistor has two leads (it’s not like a diode, which has a positive pole and a negative pole), and we can put it into the pad in any direction.
Printed circuit boards usually have marks indicating where each component should be placed.
If you need to consider the defense line of the component, there are corresponding instructions on the circuit board.
Because the word for resistance starts with “R”, the printed circuit board will be marked with an “R” where the resistor is placed, followed by the number of the resistor, such as “R3”.
So before you solder the resistor correctly, you need to find the resistor with the correct resistance according to your corresponding documents (such as your project file).
Then bend the resistor leads to a width that can fit in, as shown in the figure above, and then pass the two leads of the resistor through the two pads on the board.
Insert the lead into the pad until the component is correctly placed on the printed circuit board.
Sometimes you need to gently twist or pull the leads exposed at the bottom of the printed circuit board.
For most printed circuit boards, all components must be placed on the printed side (here we call it the upper end of the board), and then we have to solder all the pads on the bottom of the board.
You need to turn the printed circuit board over to solder the two pads. When you flip over the board, you need to support the resistor with your fingers to prevent it from falling out of the board.
Next, bend the resistor’s leads to the outside to 45° so that the components will not fall off during soldering.
How To Clean The Soldering Iron?
As mentioned earlier, the electric soldering iron is enough to melt the metal after heating. This means that the end of the soldering iron will quickly oxidize after being overheated.
which means that it will become dirty due to oxidation when exposed to the air.
In this article on how to use a soldering iron, you need to understand that the soldering iron’s maintenance is also essential.
Oxide is heat-insulating, so to better conduct heat and improve your welding efficiency, you need to remove the oxide on the head of the soldering iron before each welding.
This is why we need a wet sponge: to remove the oxide on the soldering iron head, place the soldering iron head on the wet sponge and scrape it lightly, then rotate the soldering iron and repeat cleaning.
In this way, the head of the soldering iron will be completely new and ready for soldering.
Please remember to clean the soldering iron tip like this before each soldering because it oxidizes very quickly. Only when the tip of the soldering iron is cleaned can you better solder.
Started To Use Electric Soldering Iron For Welding
Now it’s time for formal welding! Hold the soldering iron in one hand as if holding a pencil, and hold the soldering material in the other hand.
Use a clean soldering iron tip to simultaneously touch the pad and the wire of the component you want to solder. Please leave it in that position for one second to allow it to heat up smoothly.
Then add 1MM-3MM solder under the head of the soldering iron, do not add it above the tip of the soldering iron because then the melted solder will only fall on the tip of the soldering iron, which is useless.
We want to allow the solder to flow smoothly around the pads and wires to complete successful soldering.
The soldering material that does not touch the tip of the soldering iron will not melt. Once it touches the tip of the soldering iron, it will melt immediately. When you observe that the soldering is appropriate, remove the solder.
This is a very critical step in how to use a soldering iron.
Keep the soldering iron head on the pad and leads for another 1 second because the soldering material needs time to flow around the pad and lead, and it will only flow when it is hot enough.
Then remove the soldering iron and take a look at your perfect soldering! It’s easy.
Please note that the welding material will cool and harden quickly, which takes about 1 second. Then you can proceed to the next position welding.
When the tin and lead soldering materials melt, the smoke you see is produced by rosin evaporation. The chemicals in this smoke are not good for your health.
Please try not to inhale it. When welding, you can gently blow the weld to prevent inhalation of these fumes.
If you are using lead-free soldering materials, the smoke produced is terrible. When using it, you need to ensure that it is deep in a ventilated room and avoid inhaling smoke when you are soldering.
When you are not using the soldering iron, please put it back on the Soldering Iron Holder. This holder can make the soldering iron you put on the table safe enough. After all, it is not fun to put it directly on the table or your lap…
How To Judge Whether The Soldering Of Electronic Components Is Qualified?
How to use a soldering iron to complete successful soldering? So, how do we judge this welding is successful?
You can judge successful soldering based on the solder material that covers the pad and covers the lead. From the appearance point of view, the molten solder presents a small convex shape.
If you can see any uncovered holes or the molten solder’s shape on the board is flat. This means that you may not add enough solder, which may cause the circuit connection need not be formed.
If this happens, don’t worry. You need to repeat the soldering steps: after cleaning the soldering iron tip, touch the soldering iron tip to the pad and the lead for 1 second, and add 1mm-3mm solder, remove the solder, keep the soldering iron tip, the pad, and the lead in contact for another 1 second, and then remove the soldering iron, this may be able to repair the defective solder smoothly.
There is also a situation: you may add too much solder, which causes the solder joints on the pad to be too large and touch other pads, which may suggest connections that should not be there.
If you are not yet familiar with how to use a soldering iron, this situation may often happen.
If this happens, don’t worry too much. You only need to clean the soldering iron tip, place the soldering iron tip in the high-temperature state between the two pads for 1 second, and then slam the board on your workbench so that the molten excess solder is thrown onto the workbench.
Reminder: During the above series of operations, please check again that you have put on your welding goggles.
You need to control the amount of soldering material reasonably. It is feasible to use more or less solder. But it cannot be too much or too little.
For specific reasons, please refer to the previous content. Several final shapes shown in the figure above are all feasible.
Some people like to place many electronic components on the printed circuit board in advance and then solder them together.
The more conservative way is to add only one component on the printed circuit board and immediately complete this component’s soldering because this can eliminate the interference of other excessive leads.
It will be easier when using an electric soldering iron.
Besides, if too many electronic components are placed on the board at one time, soldering errors may occur, and the wrong pads are selected.
Of course, for those who are already proficient in how to use a soldering iron to solder, adding and placing multiple electronic components in advance may improve the efficiency of soldering.
How To Cut The Excess Leads After Welding? Why Cut These Extra Leads?
After soldering all the electronic components’ leads, it is time to cut off the excess leads. This ensures that the excess leads will not bend and cause short circuits in other leads or pads.
If this happens, it will form a connection we don’t want.
We can use a small wire cutter to cut the lead. One side of the wire cutter has a flat cutting edge, and the other side has a deep groove.
Place the flat cutting edge down, parallel to the circuit board, on top of the small solder joint. Squeeze the handle, and the lead will be cut.
Safety Tip #3/3: Every time you cut the lead, be sure to hold the lead to be cut with one hand and use the wire cutter with the other hand to cut the lead. The cut lead may be ejected. Please be careful not to get hit in your eyes. Wearing goggles is necessary.
If the excess lead is too short to be held, and it is long enough to cause a short circuit on the circuit board, in this case, cover the lead with your fingers, and then cut the excess lead with wire cutters.
Because the lead will be ejected in the process of being cut, in case the ejected wire will hit yourself or others. If you keep this practice, it will be safer.
Some leads are already very short, such as IC sockets, and there is no need to trim the leads at this time. These leads are too short and will not cause a short circuit due to bending.
Some wires are already very short, such as IC sockets, and there is no need to trim the wires at this time. This wire is too short and will not cause a short circuit due to bending.
If you make a mistake, it doesn’t matter. All welding errors can be corrected (although some are easy and some are difficult). Making mistakes allows us to learn better how to use a soldering iron to complete successful soldering.
Although soldering is easy, removing soldering requires a lot of practice. Therefore, if you make a mistake, you should have more practice opportunities.
When you have done many soldering practices, you will summarize more tips on how to use a soldering iron to solder. At that time, you are ready to weld anything!
If you like soldering and want to do better, you may want to buy some useful tools. But you don’t need to spend too much money to get them.
You may need to buy a suitable soldering iron with an electronic temperature display for about $25-50.
At the same time, you may also need a soldering iron stand that can hold the soldering iron and wet sponges. Of course, this item is not expensive.
The above is all about how to use a soldering iron. After reading the article, are you eager to try and want to start a practice?
Before learning how to use a soldering iron to complete successful soldering, you need to prepare the necessary soldering tools.