Summary:There are a number of options available when selecting a soldering iron. If you have used them in the past, you probably have a preference with respect to brands and designs. Or maybe you lack that experience and want to see a few options. Don't limit yourself. There are a number of excellent soldering irons out, with various features and options.
Selecting a Soldering Iron
There are a few considerations when selecting a soldering iron.
Everyone has a budget, and an upper price limit. Rather than setting an arbitrary limit, look around at the irons available for sale, to get a feel for what the typical price and features are. Decide what you can afford, and you can eliminate those above or below what your budget allows. Try to be flexible with the amounts you want to spend.
Don't just buy tools, invest in good tools.
The wattage of the iron is important. The recommended iron is often a small, low wattage unit, such as 25W (Watts).
The real concern is how fast the iron can recover when soldering. A low wattage iron will take longer to return to its working temperature than a higher (45 to 60W) iron. While a low power iron is fine for doing work on a PCB, when trying to solder larger items it will not be able to maintain its temperature. Which results in the process taking too long, possible melting of nearby items, lifting the copper foil from a PCB, or a cold solder joint.
If you want the best soldering iron for circuit boards, you don't want a large iron that's better suited to automotive work. So, the question is, "What do you want to do with the soldering iron?" The next question is whether it is for professional, educational or personal use.
The answers have a significant impact on not only your choice, but on those choices available. Once the application and environment questions have been answered it will be easier to make a selection. You can now evaluate an iron for its application, which best suits the job you have in mind for it. The alternative is a more general-purpose model that can be used for a number of different tasks.
For the most part, the iron will be used to solder multifunction decoders during installation, track feeders to the rails and the power bus, and a few other (usually) electrical tasks. You may also be planning to construct your own turnouts by soldering rails to PCB ties, or constructing brass models from sheet stock or kits. It pays to select an iron in line with your plans and requirements.
There may be parameters that you consider important, such as the ability to select and maintain a specific temperature. One feature which is important when working with electronics is an ESD safe iron. Create a short list of features you believe to be important, and use that to whittle down the list of potential irons. This will make it easier to eliminate irons which lack the features you find important and are not willing to compromise on.
For DCC, important features to consider are:
- Temperature Control
- ESD Safe
- Interchangeable tips
Other parameters you may wish to consider is ease of getting parts, such as tips, and repair parts.
Select a Few Models for Consideration
Once you have arrived at the features you must have, and eliminated those which don't meet your desired features, select some models from various manufacturers which offer those features.
Compare them against each other, and you can once again reduce the list. Once you have the short list of desired models, you can make your choice. Dealer and manufacturer websites can offer a lot of guidance and options.
Types of Soldering Irons
- Simple iron.
- Cordless iron.
- Temperature-controlled soldering iron.
- Soldering station.
The simple soldering iron is an electrically heated iron, usually between 15 and 35 Watts. They don't have any mechanism to control and regulate their temperature, and will drop in temperature during use. Larger wattage irons are not hotter, but will not lose as much temperature when soldering larger objects.
For most general soldering an iron in the range of 40 to 60W is adequate. These irons have enough capacity that they can solder a joint and recover quickly, for more consistent results and faster workflow. Again, look for an ESD safe iron.
Similar in operation to a simple iron, these are powered using a battery or a fuel such as butane. They are used when electricity may not be available, or cordless operation is required. Gas fired irons often have a variety of tips, such as one for soldering, blow torch, heat gun for heat shrink applications and maybe a hot knife.
Temperature Controlled Soldering Iron
Similar to the simple iron, they also have electronics to control the heating and temperature. Where a simple iron will lose heat energy to the work, making soldering on large items difficult, the temperature-controlled iron will regulate the amount of energy available, trying to maintain the correct temperature even when a lot of heat is lost to the work.
A common method of temperature control is by using the Curie Temperature of a magnet. When the desired temperature is reached, the magnet loses strength and a switch opens. By magnetically controlling the opening and closing of the switch, the temperature is controlled. Various temperature tips are available for this type of iron.
Most soldering stations consist of a base station housing the power supply and electronics, with an iron connecting to it, usually via a plug. Many have temperature control options available to the user. Older ones may use the Curie Temperature method found in temperature-controlled irons.
While devices like this are often found in professional and educational environments, reasonably priced units are available for the hobby user. A temperature-controlled station is a good choice for many applications both on and off the layout.
Caring for Soldering Tips
The tip of any soldering iron is the most critical component in the performance of the tool. If it cannot perform its function of effective heat transfer to the connection point, the soldering iron itself will be unreliable.
Soldering tips do wear out over time and eventually need replacing, but taking steps to care for your tips can extend their life, save you money and improve the results of your soldering work. Follow these tips to reap the benefits of proper soldering iron tip care.
One of the best preventive measures you can take to protect your solder tips is to use high-quality solder. If you use low-quality solder that contains impurities, those contaminants may build up on the tip, get it in the way of heat transfer and make your soldering work more difficult. Quality solder should melt easily at the expected temperature, while different alloys will behave differently. Poor Quality Solder will often not behave in the manner you expect and lead to poor results. Purchasing solder by reputable brands is one way to increase certainty that the product will be of a high quality. You can also test the quality of solder by heating it and observing how easily it melts.
The appearance of Solder that contains lead indicates its quality. Different types of solder acts differently, so check the manufacturer's description to ensure it performs as expected. The solder type needed depends on the materials to be soldered and whether you're using flux or not.
Keeping the temperature of your tips consistent and as close to optimal as possible will help extend their life. Excessive temperature reduces the life of your tips and can lead to poor results. Soldering station irons that have a temperature sensor can help regulate temperature without damaging your tips. These irons sense when the temperature has dipped or risen out of the intended range and automatically adjust it. Recovery time, the time it required for the tip to return to the desired temperature differs between soldering irons.
Reducing the temperature to an "idle" setting or turning off the unit when not using it for extended periods extends tip life. Some irons may even shut off if let on for an extended period of time.
Cleaning the Tip
Caring for your equipment means knowing how to clean soldering iron tips. Keeping your tips clean is crucial to ensuring that they perform properly, and it can also extend their life. Your tip is clean when it appears bright and shiny. Before soldering, use alcohol and a clean cloth to remove contaminants such as grease, corrosion and oxidation from the surfaces to be soldered, if needed
Clean your tips using either brass or stainless steel wool. Brass wool is softer and less abrasive, while the harder stainless steel wool has a longer life. Metal wool effectively removes dirt and contaminants while it avoids issues associated with using a damp sponge to clean soldering tips. Frequent wiping on a damp sponge causes repeated changes in temperature, causing the tip to expand and contract repeatedly. Paper towels or a rag can also be used to wipe the tip clean
To remove small amounts of contaminants from the tip using metal wool, gently dab them into the wool. For more stubborn residues, hold the iron firmly and apply more pressure when rubbing it against the wool. Vary your strokes to remove contaminants from all the sides and edges of the tip. After cleaning, immediately tin (wet) the tip with fresh solder to prevent oxidation. If a tip does become oxidized, tin it several times with a rosin-activated, flux-cored solder. Once clean, wipe the excess off and cover the tip surface with a thick coating of solder.
When many metals come into contact with the oxygen in the air an oxide layer is formed. This layer of oxidation prevents solder from adequately wetting the joint and negatively impacts the quality of the soldering joint. Flux may come in paste or liquid form, or it may be in the core of a soldering wire, which allows it to work as you are soldering the part with no extra effort. Avoid dipping your tips into flux to clean them, as the substance is corrosive. Using wire solder and water-soluble flux for touch-up and rework operations will still hasten tip failure.
No-clean flux is only for soldering parts that require little to no cleaning. Their mild cleaning action normally isn't thorough enough to remove oxidization from soldering iron tips. A badly oxidized tip will be easy to spot because of “burnout,” which is the appearance of black or brown coating.
You should tin your tips before and after each soldering session, as well as in between soldering every two to three joints. You want to keep your tip tinned at all times; from the first time you use it until you discard it. When you tin a tip, you cover it with a thin layer of solder.
Tinning stops tips from oxidizing by creating a protective layer between the air and the iron. It's essential to keep your tip tinned, as iron rapidly oxidizes. Oxidation prevents the tip from transferring heat efficiently. Preventing oxidation through tinning also extends the life of your tips.
Keeping your tips tinned also helps make soldering easier. It helps your solder wire melt and flow better, making soldering easier. The coating creates a heat bridge between the tip and the part you're soldering, which increases the efficiency of the heat transfer.
To tin a tip, follow these steps. ... Clean the tip using the metal wool, a damp sponge, or a rag Apply fresh solder to the tip. Use a small amount — enough to coat it thoroughly.
If you are just starting your session, begin soldering as soon as you finish tinning the tip. Throughout the project, clean and tin your tip every few joints. When tinning a tip upon completing a project, wipe the tip again briefly after tinning and then turn the iron off and put it away.
Cleaning an Oxidized Tip
If a tip becomes oxidized, it will appear dark, and you may be unable to tin it. To fix this, use a tip activator to reactivate or re-wet it. To reactivate the tip, dip it into the activator and move it around until the tip starts to become shiny again. The fine abrasives and additives in the activator break down and remove the oxide layer.
Once the tip looks clean, remove it from the activator and finish cleaning with brass or steel wool. Coating the tip with solder by re-tinning will remove any remaining contaminants. Reactivating your tips using this method will keep your tips in good condition, make soldering easier and improve the quality of your results.
Storage of Tips
The way you store your soldering iron tips can also impact how well they will perform and how long they last. When storing a tip for a short period, such as between soldering joints in one soldering session, leave it in the iron, in the iron's holder. Ensure it does not stay at the operating temperature, as this will decrease the life of the tip. Lower the temperature if possible, and raise when you plan to do more soldering
When storing your tips over an extended period, clean and tin them before putting them away, which helps prevent oxidation. After they cool, you may want to store them in a sealed container, to further protect them from oxidation, humidity and contamination.
When storing a tip in the iron, loosen the nut or screw that holds it in place before putting the iron away. This helps prevent the tip from becoming stuck in the iron, an issue known as seizing. Before using an iron, it helps to loosen the nut, pull and push on the tip a few times, and then tighten the nut. This helps break any surface corrosion from the mating surfaces.
Changing and Replacing Tips
Often you just loosen the nut holding a sleeve in place, remove it from the iron, pull out the tip and insert the new one, and replace/retighten the sleeve.
Always use genuine factory replacement parts designed for your soldering iron. Others may not fit or work correctly.
Identifying a Worn Out Tip
- The iron plating has a hole and solder is eroding the copper beneath
- The plating has oxidized, becomes black and solder will no longer wet the tip
- The tip's mating surface with the heater has become oxidized and no longer conducts heat efficiently