A soldering iron is a tool used in "soldering" which is the process of fusing two or more metals together through an auxiliary material that involves an alloy called solder. Soldering is primarily used in electronics repair and applications to solder components to a printed circuit board (PCB) or connect wires.
Soldering is also used in many other aspects such as: jewelry, joining stained glass and wood burning (for design purposes), etc. The main purpose of a soldering iron is to melt solder.
However, sometimes the soldering iron is not hot enough to melt the solder. So what could be the problem preventing the soldering iron from melting the solder?
Here are some possible issues:
1. The heating element of the soldering iron is broken
2. Low power soldering irons (especially cheap ones)
3. The soldering iron does not have enough time to heat up. Besides, sometimes the soldering iron is not plugged into the power outlet properly
4. The tip has been oxidized
5. The temperature of the soldering iron is not high enough
6. Use solder with impurities
We need to focus on the heating element and tip of the soldering iron we use, because these two parts may be the main reason for the low heat of the soldering iron.
Heating element: It transfers heat to the tip of the soldering iron through electricity
Soldering iron tip: It’s an important part of the soldering iron, the solder is melted by the heat of the soldering iron tip, and mix two or more metals together.
Reason 1: The soldering iron is not hot enough: the heating element is broken
The heating element is an important component because it converts electrical energy into heat and transfers it to the tip of the soldering iron. If you suddenly feel the solder melting slowly or not melt during use, it is possible that the heating element has stopped working for some reason.
Reason 2: The soldering iron is not hot enough: it is not properly plugged into the socket
Why the soldering iron doesn't heat up seems like a silly question, but it's probably been happened to us many times.
The main reason could be that you didn’t push the plug into place, or you accidentally bumped your power plug, preventing it from making full contact with the outlet.
If you find that the tip of the soldering iron is not heating or not heating enough, you first need to check and make sure that the power cord of the soldering iron is fully plugged into the power outlet. Many soldering irons now have a status light. When the light is on, it means the power supply is normal, and if it is not on, it is abnormal.
So like the above problem, we can judge whether there is any abnormality by observing whether the status light of the soldering iron is on.
Reason 3: The soldering iron is not hot enough: doesn’t have enough time to heat
It would be great if the soldering iron reached the target temperature immediately after power on
But unfortunately this is not possible, it takes a certain amount of time for the soldering iron to reach the standard temperature, and each soldering iron has its own start-up time to reach the standard temperature. So, if you try to melt the solder 5 seconds after the iron is powered on, you may have some problems. Most manufacturers have manuals on how long the soldering iron needs to heat up to reach the standard temperature, which you can look at and know how long you'll have to wait. If there is no specific time, you can have a try and calculate how long it will take to eliminate your anxiety about later use.
Reason 4: The soldering iron is not hot enough: because of the solder
In the soldering process, there are generally three types of soldering: soft soldering, hard soldering and braze soldering. Each of these three soldering types has their own specific application, and each soldering process uses specific solders that require a certain temperature to be melted.
1. Soft Soldering - A temperature of 90 – 450 °C (190 – 842 °F) is usually used. The type of solder used tends to be an alloy containing tin and lead.
2. Hard soldering - Use temperatures above 450 °C (842 °F). This type of soldering uses brass or silver solder. A blowtorch is used to reach this high temperatures to melt the solder.
3. Braze soldering– also use temperatures above 450 °C (842 °F). It is very similar to the temperature of hard soldering.
If you mix their solder together, your soldering iron probably won't get hot enough to reach those temperatures and melt the solder.
Another problem is the thickness of the solder you use. The thicker the solder, the higher the temperature required to melt it. You may think that your iron tip is not hot enough.
Reason 5: The soldering iron is not hot enough: it may be because you used a cheap soldering iron
Whether you buy a car or a house, you want to get a good price. But sometimes choosing something cheaper ends up doing more harm than good. This is the correct statement for a soldering iron.
I bought an AiXun soldering iron before. It heats up quickly and distributes the heat evenly, which is very easy to use. But it quit after serving me for many years. Being a cheapskate, I decided to buy a cheap soldering iron. But this brought me so many problems, it took a long time to heat up, not hot enough, heat distribution was not good, oxidate too fast. Therefore, in order to avoid these problems, I strongly recommend you to buy a relatively high-quality soldering iron with some money to facilitate your use.
Reason 6: The soldering iron is not hot enough: oxidation
The soldering iron is not hot enough to melt the solder, it is most likely because the tip of the soldering iron has oxidized. You'll know when the soldering iron is oxidized when the tip of the soldering iron turns black. Oxidation of the soldering iron occurs when the plating of the soldering iron tip becomes iron oxide.
To fix this you need to use a precision knife or 800 grit sandpaper to scrape or sand off the oxide from the tip (when it's off) until it regains its shine.
Once the tip is shiny, give it a good coat of flux (if you have. If you don't then skip this step) and turn on the soldering iron. After the soldering iron is heated, apply some solder to the tip of the soldering iron.
Here are some good practices to avoid oxidation of the soldering iron tips.
Do not leave the soldering iron idle for long time;
Turn it off if not in use for more than 15 minutes;
Avoid high temperatures (340 – 380°C) (644 – 716 °F);
After each use, wipe the soldering iron with a damp sponge and apply solder to the tip of the iron. Do this before power it off.