Let us start with what is a soldering iron used for? It is a hand tool that is used in the process of joining metal parts creating electronic bonds. They are most often used for repairs, installations, and production of items in the electronics industry. Before soldering iron, an appropriately shaped copper block was used to solder metals. However, it had many drawbacks and not enough advantages compared to a modern soldering iron.
What is Soldering?
Soldering is used to connect different metals by melting the solder on them. Solder is an alloy made of different metals (usually tin and lead), melted onto different metals using a hot iron.
Iron is called hot iron when it heats up to a temperature above 315 degrees celsius. When hot iron is cooled from this temperature, it allows a strong electrical bond.
Soldering is a very useful method of connecting different metals. However, if proper tools and methods are not used when soldering, the outcome might be a damaged product.
Things Required to Solder Metal Together
The first step when soldering has the proper equipment. Soldering is different from welding, in that it doesn’t melt the metals. Instead, it melts solder onto the two metals to join them together. Thus, the equipment used for soldering differs from that used for welding.
- Soldering Iron: The most important item when soldering is the soldering iron. Usually shaped like a pen, it has a tip that heats metal to apply solder.
- Desoldering Station: A desoldering station is used to remove excess solder after soldering or making a mistake. These stations use a vacuum/hot air to melt the solder before removing it.
- Solder: For soldering, one needs to have a certain amount of solder as the filler material. There are many kinds of solders available in the market. It is important to get a solder with a lower melting point than the metals connected. This will allow the solder to melt first and connect with the other metals without damaging them.
- Tweezers: When soldering, the metals and solder both get very hot. This makes it very dangerous to touch them. Thus, it is important to use a pair of tweezers to hold the materials when soldering. Since tweezers come in many sizes, finding the pair that will hold the material properly is vital. The same pair of tweezers cannot hold differently sized materials.
- Solder Flux: While not as necessary as other items, having a solder flux improves the final product. Solder flux is a chemical used to clean the surface of the soldered metals. Applying solder flux makes sure that the joint won’t break easily.
Many other items make the soldering process much more straightforward, e.g., a soldering mat, soldering helping hands, magnifying glass, etc. However, these things are not as necessary, and purchasing them is dependent entirely on personal needs and preferences.
Soldering Tips and Safety Precautions for Beginners
Heating metals solder to very high temperatures. So, it is essential to take proper safety precautions not to cause injuries to oneself. When Soldering, different tools have different precautions that need to be taken.
- The element of the soldering iron heats up to above 400 degrees celsius. Thus, it is important never to touch the element.
- It is best to use a pair of tweezers to hold the metals that are being connected.
- When not in use, unplug the soldering iron. It is best to leave the soldering iron in its stand instead of the workbench.
- Always keep a wet sponge nearby when using the soldering iron for cleaning.
- When working with solder, it is important to wear protective goggles and gloves. This is vital so that any solder does not damage these sensitive parts.
- Usually, it is best to use solders that lack any lead or rosin content. Lead and rosin are harmful to the human body and give rise to severe illnesses. Thus, it is recommended to avoid these substances whenever possible.
Solder Flux (Toxic Fumes):
- Solder flux is a chemical, so it is best to wear gloves while using it.
- After soldering, it is important to wash both hands with soap. This will ensure that no residue is left on the body.
- Most of the toxic fumes that are generated come from the solder flux. Thus, the soldering should be done in a well-ventilated area. This will ensure that the build-up of toxic fumes doesn’t cause eye and throat irritation.
- The smoke generated by the burnt flux is a potential cause of respiratory diseases. It is best to avoid breathing it by keeping the head away from the smoke. In some cases, a fume extractor is necessary to filter the air near the workstation.
Electrical and Fire Safety:
- When using soldering iron, it is important to use a grounded outlet to reduce the risk of a short circuit.
- Since soldering is done at high temperatures, it is recommended to work on non-flammable surfaces. The person’s clothing soldering should also be fire-proof and should cover the entire body.
- Wires/cables that are connected to power should never be soldered.
- It is also important to have a fire extinguisher near the soldering area. The person soldering should know how to use the fire extinguisher properly.
The workers performing the soldering should be familiar with the proper first-aid methods. This will increase the probability of avoiding serious injuries in the workspace. It is also important to have proper waste disposal as soldering requires hazardous chemicals. Things like contaminated rugs, solder flux, sponges, etc., are harmful to the environment and cannot be disposed of like normal waste.
Process of Tinning the Soldering Gun Tip
Tinning is the process of coating the metals to be soldered with a thin layer of tin. Tinning is pretty standard when soldering copper pipers, plates, and electrical wires. It helps to improve and prolong the soldering.
How to Tin a Soldering Iron for the First Time?
- Tinning starts with the tip of the soldering iron. This helps the tip to last longer and makes the process of soldering easier.
- After using the tip for a while, they generally show black spots and rust on them. It is important to tin the tip before further use.
- First, heat the tip to room temperature. Then clean it using a brass cleaner or any wet sponge to remove all the dirt and debris.
- After cleaning, apply a small amount of solder to the copper part of the tip. Wipe away any excess solder remaining on the tip.
- A similar process is done with the materials that are to be soldered. First, they are heated and cleaned before applying a thin solder layer on them.
Tinning helps to clean up the soldering process. It also helps create strong bonds between the soldered materials that are usually not possible.
How to Use a Soldering Iron on Different Surfaces?
While soldering is a straightforward process, several different measures have to be taken when soldering different types of materials. For example, soldering a wire is not the same as soldering a PCB.
Soldering a Wire
Wires are usually soldered by hand. They don’t require any special machinery to be connected. Let’s see how to solder wires with a soldering iron
- The wires are properly prepared before the soldering. Each of their filaments is twisted together, so they behave like a single entity. Sometimes, a small soldering resin is added to the filament to help tangle the wires.
- The cables are then tinned. This makes the job of soldering the splice much easier. This step also decreases the probability of melting through the wire’s shielding.
- Since the wires need to resist being pulled apart, it is best to wrap them around each other before soldering. If the wires are only soldered, they risk being pulled apart later.
- Now, the soldering iron is applied, and the solder from each cable melts to form a solid joint. Make sure that all cracks and gaps are correctly filled.
Soldering Printed Circuit Boards
PCBs are soldered using a process known as the wave soldering process. A wave solder machine is used for soldering PCBs.
- The first step in this process is melting the solder. The wave soldering machines have a solder tank built into them. This tank is heated to melt the solder.
- Before the soldering process, the components of the PCB are thoroughly cleaned. If any oxidation is detected, it is also removed.
- Then, the printed circuit board is placed on the melted solder. The board is held with metal clasps that ensure the solder’s proper placement.
- After making sure that the board is in the correct position, the solder is applied. Enough time is given for the solder to settle into the joints. It is also ensured that no bumps are formed.
- After the soldering is complete, any flux residues are cleaned from the PCB. The circuit board is properly cleaned using deionized water and other solvents that won’t damage any components.
The process of soldering different materials goes differently depending on the type of material, size, shape, etc. That said, if some basic steps are followed, most materials can be soldered pretty quickly.
How to Desolder?
When soldering, the need to desolder two metals can arise at any time. Sometimes, mistakes are made while soldering, and the joint may need to be redone. Desoldering can be done using a few tools.
Desolder Using a Soldering Iron
- The first step is to heat the solder joint. Only when the solder is in liquid form can it be removed.
- Then, iron pins and other sharp objects are used to pierce the soldering. This is done to remove the solder from the joints.
- A plier is then used to pull the pins out while the components are still hot.
Using Desoldering Pump
- To use a desoldering pump, first, the solder on the components needs to be hot. A soldering iron can be used to melt the solder.
- The pump has a plunger built-in. This plunger is pressed down on the solder to be removed when it is hot enough.
- After the plunger is released, it will remove the unwanted solder. A desoldering pump can remove solder by creating a high-pressure vacuum to absorb the solder.
- After the solder has been removed, the free components can be moved.
Just like soldering, desoldering too is a simple process. It is important to follow proper safety measures to ensure that the person working is not harmed. Other tools like a heat gun and compressed air too can be used to desolder joints.
Soldering Iron Uses – What Can you Solder?
Soldering can be performed on metals with a melting point lower than 450 degrees celsius. This is because a soldering gun can only heat up to around this temperature. So if the soldering iron doesn’t melt the metals, they can’t be soldered.
Metals like copper, silver, gold, and brass have a melting point below 450 degrees Celsius. This allows them to be soldered. Most metals with a low melting point can be soldered.
Soldering iron will heat up very quickly, approximately from 30 seconds to 3 minutes based on the brand and quality.
Soldering is melting the solder on top of two metal components to join them together. The joint is not necessarily strong, but solder metals are highly conductive. This allows electricity to pass easily through the joints. Thus, soldering is more popular in the electrical industry. In addition, things like wires, PCBs, metalwork, pipes, and musical instruments generally use soldering.