Soldering differs from welding. In welding, the component pieces are melted together; in soldering, a softer metal with a lower melting point is used to connect them. [2] X Research source Because soldering doesn’t melt components, it’s useful for more delicate applications, such as electronics work, or plumbing. The purpose of soldering is to bind two other components. Solder can be thought of as a sort of “metal glue. ” It can be used to fill in gaps or hold pieces in place, but doesn’t serve any more complicated purpose. Since solder is metallic, it conducts electricity, which is another reason it’s so popular for connecting electronic components.
Solder is typically composed of two or more metals combined into an alloy. Silver, antimony, copper, tin, and zinc are all common ingredients. Solder is soft and flexible. It generally comes in a coil, or spool, that can be stretched and bent. Solder has a low melting point, and cools extremely quickly after it’s been melted. [4] X Research source (350F - 500F) Solder can contain a flux core of natural rosin (tree sap) or a chemical acid. The metal of the solder encircles the core, like a tube. The purpose of the core is to serve as a flux, or purifying agent. The flux prevents oxidation in the solder as it cools, keeping it strong and pure.
Most soldering irons typically heat to between 800 and 900 degrees Fahrenheit, so exercise caution when using one. [6] X Research source Soldering irons tend to catch a veneer of solder after each use, which can oxidize and reduce the iron’s effectiveness on the next use. To clean this off easily, secure a wet sponge before you turn your iron on, and gently drag the tip across the sponge once the iron is heated. A layer of fresh solder on the tip can actually make a soldering iron more effective. This process is called “tinning,” and is done by allowing a bit of fresh solder to melt evenly over the tip before use. Better models of soldering iron come with a heat control that can be adjusted for different projects and types of solder.
Clamps or alligator clips, for holding components in place while you solder them Thick gloves, to protect your hands from the tip of the iron as you feed solder to it Safety glasses or goggles, to prevent any errant solder flecks from hitting your eyes A solder stand to rest your soldering iron on between applications.
If you need to solder somewhere without much light, bring a bright light (such as a portable lamp) with you.
Soldering irons don’t have exchangeable tips, so you’ll need to buy the one(s) you want. Fortunately, they start at around $15 in price, and a good quality iron can be had for around twice that. A typical soldering iron for electronics work will be a 40-watt iron that has a temperature (or a temperature setting) of 900 degrees. This allows the iron to easily melt electronics solder without damaging the small wires of the components themselves.
60/40 tin and lead solder used to be the standard for electronics soldering, however due to the toxicity of lead it has fallen out of favor. Tin and silver solder is generally preferred today. The silver raises the melting point slightly to 430F, raises the price, but helps the solder to bind more smoothly. The numbers in solder descriptions are percentages of the element in the solder alloy. (60Sn/40Pb = 60% tin and 40% lead)
For most components, use a small clip or clamp to hold them in place once you’ve set them.
Quickly touch your solder wire to the soldering point, and apply the iron to it. The solder should melt immediately. Soldering to a PCB board should never require more than about 3-4 seconds’ worth of molten solder. If more solder is required to secure the connection, feed it smoothly with your hand. Your solder should pool loosely, forming concave sides as it spreads around the component wire. It shouldn’t ball up or look lumpy.
Be sure not to blow on the solder or otherwise try to help it cool. This can make it lumpy or add impurities.
Re-tin your iron’s tip every several applications, and once more before you put the iron away. This helps extend the life of the iron. [12] X Research source
Specialized soldering irons can be used for pipe soldering, but a propane torch is just as effective for most jobs, and much cheaper.
Absolutely avoid using leaded solder for soldering your pipes. Be sure to closely read the label to determine the alloy composition. Pipe solders tend to compose mostly tin and may also contain antimony, copper, and/or silver.
Before you turn the water off, pour a bucket of water. Keep the bucket nearby in case your torch catches anything on fire.
Take it slowly. A tube cutter works best with slow, steady movement. Go too quickly and you might dent the pipe. For larger pipe, you’ll have to use a hacksaw. File off the ragged edges afterward. Once the pipes are cut, fit them into whatever joints you’ll need to solder tight.
A smooth and clean surface will allow the solder to flow into the joint smoothly and seal it evenly.
Maintain even heat by moving the flame all around the work area. Once the pipe is good and hot, apply the tip of your solder wire to the place you need to seal. It should melt right away. Hold the solder on the opposite side of the pipe from your torch. It should flow around the joint and fill it up all the way around. Let the joint cool. It will cool quickly. Move on to the next joint that needs sealing, if necessary.
