An Introduction To Safe Soldering
Soldering is used to permanently join electronic components using a molten mixture of lead and tin (solder). Soldering is like gluing with molten metal!
One of the most common applications of soldering is permanently mounting electronics components onto printed circuit boards (PCB).
Solder is an alloy of tin and lead, with a melting point of around 180 degrees Celsius. That s 356 degrees Fahrenheit!
The best solder for electronics work is a thin rosin core solder. Rosin is a wax-like substance that helps to keep your electrical connections clean while you solder.
Rosin core solder comes in three main types - 50/50, 60/40 and 63/37. These numbers represent the percentages of tin and lead in the solder. Our class uses 60/40 thin rosin core solder for our electronics projects.
Never use Acid Core Solder on electronics projects. Acid core solder is typically used on construction projects to join galvanized flashing together. Acid core solder will corrode electronic components and ruin your printed circuit boards.
Soldering irons are the heat source that we use to melt the solder. Our electronics lab uses dual-heat soldering stations. Our soldering irons use 20 Watts of power on the low setting, and 40 Watts on the high setting.
The Low Power setting is ideal for soldering electronics components onto printed circuit boards. Power Switch The High Power setting is for heavier work such as soldering large wires or terminal strips.
Our electronics lab also has a gun-style soldering iron available for students to use on their projects.
Before you begin your soldering project, apply a thin coat of solder to the tip of the iron. This process is known as Tinning the iron.
Safety Precaution # 1 Always wear safety goggles when soldering.
Safety Precaution # 2 Be careful Soldering irons are HOT. The tip of your soldering iron can reach temperatures of as high as 440 C (824 F). Always protect yourself from burns, and never allow your soldering iron to come in contact with combustible materials.
Safety Precaution # 3 Soldering creates fumes which can be harmful to your eyes and lungs. Always work in a well ventilated area.
Safety Precaution # 4 No Horseplay in the shop!
Safety Precaution # 5 Always place your hot soldering iron back in its stand when you are not using it. A soldering iron left on the table can easily start a fire or burn someone.
Safety Precaution # 6 Be sure that your electrical cord does not snag. A snagged cord can cause you to drop a hot soldering iron into your lap.
Safety Precaution # 7 Never solder on a live electrical circuit. Unplug the cord and remove all batteries from your project before you begin soldering.
Safety Precaution # 8 Use a magnifying glass rather than putting your face up against your soldering project. Not only will this help you see what you are doing, it will protect your face from being burned and keep your nose a safe distance from caustic fumes.
Safety Precaution # 9 Maintain a safety zone around students who are soldering. Avoid crowding or bumping into students when they are using soldering tools and equipment. Stay back and give them space to work so they can focus on what they are doing.
Component Placement Students often have difficulty holding their electronic components in place. while they solder them. Try bending the leads on the bottom of your printed circuit board at a 45 degree angle. That will help to hold the component in place while you solder it.
Soldering Techniques Applying the Heat Lay the soldering iron tip so that it rests against both the component lead and the printed circuit board.
Soldering Techniques Applying the Heat It usually takes two or three seconds to heat the component up enough to melt the solder. Hold the tapered surface of the soldering iron (not the tip) firmly against the parts. The soldering iron should be at about a 45 0 angle to the work surface.
Apply Solder And Remove Heat Once the component lead and solder pad has heated up, you are ready to apply the solder. Touch the tip of the rod of solder to the component lead. Do NOT allow the tip of the iron to touch the solder itself.
Soldering Tip # 1 It is always a good idea to secure your work so that it doesn't move during soldering.
Soldering Tip # 2 Keep the soldering iron tip clean Sponge Use the wet sponge on your soldering stand to clean the tip between joints.
Soldering Tip # 3 Use Heat-Sinks and Sockets Some electronics components are sensitive to heat and can be damaged by your soldering iron (such as Integrated Circuits and transistors). Socket Sink Clip-on heat-sinks can be used to protect sensitive components during soldering. Sockets can be used to mount ICs to your printed circuit board without needing to apply damaging heat directly to the sensitive IC chip.
Soldering Tip # 4 Avoid Cold Solder Joints A cold joint is a joint in which the solder does not make good contact with the component lead or printed circuit board pad. Cold joints make poor electrical connections and can sometimes actually prevent your finished electronics project from working.
Soldering Tip # 5 Use a magnifying light stand Sometimes it is difficult to properly see very small electronics components while you are soldering them. Use a bright light stand a with built-in magnifying glass to help you see your work. This type of light stand has the added advantage of allowing you to use both hands for soldering.
Common Causes Of Cold Solder Joints 1. Moving your work as the solder is cooling. 2. The joint is dirty or oily. 3. The work was heated to an improper temperature. 4. You applied solder directly to the hot soldering iron.
Tips and Tricks Remember that melted solder flows towards heat. Most beginning solderers use too much solder and heat the joint for too long. Do not move the joint until the solder has cooled. Keep your iron tip clean. Use the proper type of solder (60 /40 thin rosin core).
In electronics, de-soldering is the removal of solder and components from a circuit for troubleshooting and repair purposes. A de-soldering tool is like a small handheld vacuum that removes molten solder from your printed circuit board.
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