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Temperature setting is a crucial part of soldering. The temperature of the soldering iron must not only be appropriate for the component or work-piece, but it must be suitable for the solder you are using in your soldering project. Many find it difficult to determine the accurate temperature required for a specific solder. For beginners, it seems almost impossible to find. I have noted down some basic points to remember, which will help you in choosing the right temperature for your solder. But before that, you must also know its importance.
Why is Right Temperature Setting Important?
You should always set the appropriate temperature because working temperature influences tip durability the most. Setting the accurate temperature will help to prevent overheating and soldering with insufficient temperatures. Both can create major problems during soldering.
Too much heat can result in overheating of the connection area and lead to lifted lands, board damage, poor solder joints, overheated solder, and increase in oxidation, resulting in unnatural corrosion of surface plating of the tip. Excessive heat applied to the solder can cause it to boil, which will create bubbles on the joints, resulting in bad connection.
If the temperature is too low, it will take more time for the solder to melt. In case the solder isn’t heated properly, the connections will be weak. Also, lower than required temperatures may lead to poor heat transfer, resulting in lesser productivity and poor quality solder joints.
Types of Solder and their Melting Points
Different types of solder come with different melting points. You must know the type of alloy you are using and it’s melting point so that you can adjust the temperature of the soldering iron according to that. Given below are the most commonly used solders:
This solder is composed of 50% tin and 50% lead, with a melting point of 417°F. Below that it remains liquid partially until the solder cools to 361°F and then solidifies, giving it a working range of 56° F to completely harden from its melting point. For this solder, you would want to keep the temperature of the iron slightly above 417°F.
This type of solder contains 60% tin and 40% lead. Depending on the particular composition, it has a melting point of around 374° F. It remains partially liquid until it cools down to 361°F. This has a working range of 13°F. For individuals working with this solder is recommended to use the iron tips with temperature compatibility of at least up to 572°F.
This solder is composed of 63% tin and 37% lead. It has a melting point of 361° F, and also it becomes solid at 361° F, giving it a working range of 0 degrees. This type of solder is also known as eutectic alloy which means at 361° F, it can go instantly from solid to liquid and back to solid simply by applying or removing the heat source at the solder’s melting temperature of higher.
Lead-free solder usually has the highest melting point as compared to the alloys containing lead. Based on the specific composition of metals, lead-free solder will produce variable liquid, solid, and working range temperatures. For working with lead-free solder, the iron tip must also be lead-free. Most no-lead solders melt at the temperature of around 446 °F.
Finding Melting Temperature
Some of you might be using solder other than the ones mentioned above. As the melting point depends on the ratio of alloy’s composition, finding the exact melting point is quite difficult if it’s not mentioned on the package of the solder that you have purchased.
However, if you have enough patience, you can conduct a small experiment by setting the temperature of the tip between the range of 350°F and 450° F and applying it to the solder. The least temperature at which your solder melts is the melting point of the specific alloy. This can be pretty much time consuming.
Adjusting the Temperature
Once you have begun soldering you must always consider maintaining low working temperature to prevent the flux from burning and producing low quality solder connections and also making them fragile. In fact, most individuals prefer keeping the temperature only slightly above the melting temperature of the solder.
However, if you see that the solder is unable to melt fast enough you will want to choose a higher temperature, which must not be done as too much temperature will only cause damage. Instead, you should choose a larger tip with better surface contact, so that the heat can be evenly transferred to the solder.
Adjusting the correct temperature is very important not only because it improves the outcome, but also it influences the life of your soldering tip in the long run. It can be confusing for starters, but if you know the alloy well, then you can easily adjust the precise temperature based on it.