Which solder to buy

At its simplest form, it consists of a metal tip, a heating element that brings the tip up to soldering temperature, an insulated handle to allow safe holding of the soldering iron, and a plug for either a wall outlet or the soldering station.

It has a copper interior, which acts as an effective and efficient thermal conductor. It also has iron plating to protect the soft, corrosive-prone copper from flux and solder, and chrome-nickel plating to keep the flux from wetting up the tip. Beyond that, there are options that provide better control over the soldering iron temperature and heat response time it takes to heat up again after soldering. These include soldering tips, which are metal slugs that rest against the heating element, and others which are integrated with the heating element in a cartridge.

On the low end, most appropriate for hobbyists, a soldering iron may plug directly into the electrical wall outlet, which provides no control over soldering iron temperature. Just on or off. With a soldering station, the soldering iron plugs into the station for greater control over temperature, and other features like set-temperature memory, lock-out, etc.

While there is a large variety of different types of solder, at the most basic, you need to choose between lead or lead-free, the diameter of the wire, flux core or solid wire, and the type of flux.

If you are repairing or assembling electronics for use in the US, lead solder is the easiest to work with and it forms the most reliable solder joints. The lower heat also generates less thermal stress on the rest of the PCB.

If the end product is being shipped outside of the US, especially to Europe, you should consider lead-free solder. An exception might be for high-reliability electronics like those used in aerospace. In that case, check with the specifications and requirements of the end-user of the electronics.

Lead-free may still be required, but there may be exemptions in place that allow for the use of lead solder. Think of flux and a prepping agent for the soldering process. Flux removes any oxidation that may be present and slightly etches the surface to promote wetting.

No-clean flux is a good choice for soldering where cleaning is to be avoided. The light residue can be left on the board, or removed with a flux remover.

Rosin activated flux RA provides excellent solderability in a wide variety of applications. It is best to remove the residue after soldering for aesthetics and to avoid corrosion down-the-line.

Water soluble flux OA is a very active flux engineered to be removed easily with DI water, like in a batch or in-line system. It can also be removed with isopropyl alcohol IPA. It is very important to clean off water soluble flux residues because they are highly corrosive. These classifications are for companies that have green initiatives, or have to comply with halogen restrictions due to regulatory or customer restrictions. Halogens include chlorine, fluorine, iodine, bromine and astatine elements.

If soldering a simple connection, like 2 wires, or a thru-hole lead, the flux in a flux core solder should be enough. For more complex soldering techniques, like drag soldering multiple leads on a surface mount component, additional flux may need to be added. The flux is activated and consumed when it originally flows from the core. If the solder is worked further, like when you drag across multiple leads, you run the risk of cold joints or bridging without additional flux. While more flux seems like it should be better, take care not to over apply flux.

Flux can be painted on with an acid brush, or applied with either a needle bottle dispenser, or a pen dispenser. You want the tip hot enough to melt the solder efficiency, but excess heat can damage components as the heat travels along the leads, and it will reduce the lifespan of the soldering tip. Inspect the solder joint to make sure there is full coverage over the contact area and lead. Some things to watch out for:. The goal is to match the tip shape and size to the contact pad.

This allows you to maximize the contact surface area, so that you heat the lead and contact area as quickly as possible. If you choose a tip that is too large, you have more tip volume to heat, which will slow down the heat recovery - the time it takes for the tip to reheat after soldering a joint. It also runs the risk of interfering with other components and contact areas. It will take more dwell time, which slows you down and could increase the thermal stress of the component. Make sure you are using a soldering iron and tips intended for electronic PCB soldering.

Tips intended for other applications, like stained glass, plumbing, or heavy electrical work, are generally much larger than what is appropriate for electronics. Soldering tips come in all kinds of shapes to facilitate different PCB geometries:. The solder will tend to melt but just drip off the tip. This makes it difficult to move in order to solder around contact areas the way you may need it. The purpose is to remove excess flux and solder from the tip. If too much flux builds up and burns onto the soldering tip, it will eventually dewet and be unusable but not necessarily unrecoverable.

Unless the tip cleaning tools are used properly, they can do more harm than good. When choosing a sponge, make sure it is made of natural cellulose like Plato replacement sponges. Synthetic sponges will melt onto the soldering tip and can shorten tip life. Use clean DI water. Tap water may include minerals that can build-up on the tip.

When you saturate the sponge, wring it out so that it is not dripping wet. Too much water can increase the thermal stress of the tip, and slow down tip recovery.

When the soldering tip has turned black from baked on fluxes and no longer wets properly, it is time for the cleaning tools of last resort. Tip tinner Plato TT is a combination of lead-free solder and cleaner.

While the soldering iron is at full temperature, roll it in the tip tinner. As you roll it, it should change from black to shiny silver as the baked flux is cleaned off. Then wipe off the excess tip tinner from the soldering tip, and re-tin using wire solder. Polishing bars are also available and are used to scrub the tip clean of flux residues.

This should only be used as a last resort because you will be removing iron along with the burnt flux. Once a tip shows pitting - actual holes in the iron - it is time to be replaced. Remember to use a jabbing motion using a brass tip cleaner. Wiping across the surface increases the likelihood of flinging molten solder. Since the move from lead to lead-free solders, a common complaint has been short tip life.

The higher heat needed for lead-free solders and flux combined with greater activity leads to faster tip burn-out. Often the tips turn black, the solder beads and just drips off the end of the tip. Soldering tips have a copper core that transfers heat from the heating element to the working end tip of the tip. The spool size of the solder is high as it comes in 1 lb spool roll. But all in all, it offers superior flow and is best suited for broad DIY electronics and stained glass soldering.

The rosin core flux content on the soldering wire stands at 2. It has a normal and low melting point of degrees Fahrenheit and thus easily melts and Solders onto the place making clean and strong joints of elements. Mostly, it has a very low smoke output and the joints are clean and neat. A spool of solder might seem like a very generic thing.

More of a one size fits all model but serious DIY electronics enthusiasts would understand that Solder comes in various types, sizes and compositions. Solder is not only used for creating conducting joints in Electronics but also in Plumbing as well. In this buying guide, we are going to discuss the different types of Solder available, different compositions and much more.

Basically, solder is available in the forms of wire spools, bars, paste or even pellets. Most of the times, it is available in the form of a wire as basic DIY enthusiasts would associate with it.

Sometimes, a soldering paste is also common that is mostly used for SMD soldering. The main difference between a lead-based solder and a lead-free solder would be the melting temperature. Lead-based solder has a relatively low melting temperature and also has a low price point as well. But owing to the healthcare concerns of inhaling lead vapours, people are being encouraged to move to a Lead-free solder. Lead-free solder also gives you high-performance and strong joints with great conductivity.

They are also neat but may cost a few cents more than a lead-based solder, nothing uncommon. As we have mentioned above that Solder is not only associated with electronics, plumbing requirements are different than electronics.

We are now going to look at a few factors that you would be considered while choosing solder for Electronics. Type of solder refers to how you would want the solder to be. Would it be in a solid format? Spool of wire?

Or Pellets? Pellets or wire are the most common type and if you are a beginner DIY enthusiast, we would recommend that you go ahead with a spool based wire type of solder. They are easier to handle, have better melting points and form really good conductive joints as well. Composition of a solder refers to the constituents of what the solder is made up of. As we discussed just now, depending on your choice of project, you would be going forward with the choice of a lead-based or lead-free Solder.

While lead-free solder is a highly preferred one, owing to the lead-based solder may be harmful , you can go with a mixed one too. The mixed type of solder will come to a majority of tin percentage in the solder with only a minor percentage of lead in them.

Pick wisely. Larger the diameter, larger and broader is the joint. For broader applications like strain glass or maybe even larger PCBs with larger elements, you would be going forward with a larger diameter of about even 0.

Generally speaking, you would want either a 0. Flux helps to remove any possible oxidizing metal from the surface that you are about to solder to prevent any fragile joint. The flux would help to seal the joint into a strong air seal or an airlock. Flux would improve the wetting characteristics of the liquid solder and thus facilitates amalgamation. There are a lot of different types of fluxes that are used in electronics and plumbing but the most common and preferred type of fluxes are rosin and acid core.

An acid core is mostly used for plumbing purposes and for electronics, you would be going for a rosin core flux. Another thing that you would be considering is the flux content also. Indium lower the melting point, improves ductility, and is used for soldering to gold or for cryogenic applications due to its high resistance to temperature swings. Indium alloys are expensive and prone to corrosion. Nickel in solder alloy can protect UBM under bump metallization layer from dissolution.

Silver provides mechanical strength, but with lower ductility than lead. It can improve resistance to fatigue from thermal cycles in lead-free solders. The wide variety of solder blends can help you find the right combination of properties for your electronic device. Often it is the specific combination of elements in a solder blend that can be used to get a certain result.

In70Pb30 is compatible with gold contacts low gold leaching and has high resistance against fatigue under thermal cycling. SAC Sn-Ag-Cu is a lead-free solder popular in Japan for reflow soldering and wave soldering, a bulk soldering process where the circuit board is passed over a pan of molten solder.

Waves wash over the board, soldering the components. In summary, there are three main types of solder: lead-based, lead-free, and flux. Lead-based solders are the best understood, are reliable, and preferred in mission critical applications such as aerospace or medical electronics.

Lead-free solders are available for electronics that need to meet health and environmental requirements. And flux solders contain a rosin reducing agent at the core that is released during soldering removing oxidation from the bonding site.

For most hobbyist applications your standard Sn60Pb40 solder is fine. Picking the right blend is about identifying the requirements you need to meet, finding the right properties to meet those requirements, and optimizing for cost.

Pick the best solder for your needs. Cadence PCB solutions is a complete front to back design tool to enable fast and efficient product creation. Cadence enables users accurately shorten design cycles to hand off to manufacturing through modern, IPC industry standard. To validate the integrity of PCB assembly, circuit board manufacturers rely on automated circuit board testing systems. Choosing the best-priced components to use on your circuit board can save you a lot of money as long as you look at component cost volume analysis first.