How to Soldering

  • Why You Should Refrigerate Solder Paste

    Solder paste is a vital material used in the manufacturing
    of printed circuit boards. It connects surface mount components to pads on the
    board through its sticky consistency once heated and forms a bond and an
    electrical connection. Inside the paste, there are ingredients that serve as
    activators that essentially remove oxides from the surface being soldered and
    the powdered solder alloy itself once heated.

    As the paste ages, however, its physical characteristics and overall effectiveness will change. Most solder pastes typically have a shelf life of around 3-6 months when refrigerated. This makes refrigeration the best and most effective way to get the longest use out of your solder paste. Once your paste reaches room temperature or higher, the six month shelf life can shorten to as little as 24 hours. Generally speaking, the ideal temperature for most pastes is between 0 and 10 degrees Celsius. Temperatures warmer than this could separate the flux medium from the body of the paste, possibly causing printing defects and errors.

    Kester EP256 Solder Paste

    While it is not recommended to leave solder paste in warm environments, freezing solder paste is also not recommended. Placing solder paste in too low of temperatures could result in the precipitation of the activators. There are many different solder paste options, but whichever paste you buy should be stored immediately as soon as it arrives.

    Think of your solder paste as a carton of milk. You wouldn’t want to leave the milk sitting out in your car for hours before you finally arrive home from the grocery store. Solder paste generally comes in a package that has insulating materials or ice packs, but it is still recommended that you choose next day shipping and move it to a refrigerated environment as soon as possible.

    Solder paste is designed to have quick reactions at higher temperatures but remain fairly dormant at lower temperatures. This is why it is extremely important to keep the paste at the aforementioned temperature range until removing for use. GoKimco offers a wide variety of different solder pastes, but each product includes details on the recommended handling and shelf life.  

    Kester R276 Solder Paste, 35gr Syringe

  • Choosing the Best Tools When Soldering with Lead Free Materials

    photoRecent trends in electronics and other areas have suggested that lead free solder is now more popular than lead options. This being said, it is important to first understand why lead free solder may be a more viable and useful option than other soldering methods.

    Lead has long been known to be toxic making it a difficult

    Lead Free

    material to work with. While it can be harmless in some applications, it can be incredibly toxic in other instances. With electronics and other items that we come in contact with every day, it is highly important that the use of toxic materials be limited to protect consumers.

    Lead free solder paste, lead free wire solder, and lead free compatible fluxes are also necessary. The Kester Lead Free solder paste is a great option that is fairly inexpensive. You will also need lead free solder masking agent like the one offered by Chemtronics Chemask.The European Union outlawed the use of lead in consumer goods in 2008 making it essential for users to find an alternative when it comes to soldering. Lead free alternatives are far more available than ever before as more and more people are switching to lead free alternatives. That being said, it may be necessary for users to find new tools in order to work with these lead free materials.

    Choosing something like the Hakko Lead Free solder pot FX301B-03 is a great place to start. Finding a lead free solder pot is the first step to making a successful transition. It is necessary to get a lead free solder pot as it will have different temperature settings, different gauges and more which could make lead free solder unstable and far less suitable for sturdy and durable solders.

    Still another item you may need is of course lead free solder itself. This can either be solder wire like the Kester 24-6337-6401 331 Organic Water Soluble Cored Wire is a great option. These spooled solder wires are great and are easy to use and easy to work with.

    Another option is of course lead free bar solder like the Kester K100LD 04-9574-0050 bar solder. This is also easy to work with and fast for those that do not want to deal with wire spools and unspooling the solder that they need. All of these products can help you quickly switch over to a lead free solder option making your soldering safer and easier all around.

    If you're still not sure what you need for Lead Free Soldering:

    If you have questions about anything related to Lead free soldering, Kimco has the answers you need.  You can browse our website or If you prefer, you can also contact our team of professional customer service representatives for assistance with your needs by calling (800) 521-9197.


  • 3 Crucial Things You Need to Know Before Soldering With Lead Free Materials

    Lead FreeSoldering with lead-free solder presents special challenges that you should know about before getting started. Knowing these challenges can help make it more likely that you will get the results you want. Three of the top items you need to keep in mind to meet those challenges are outlined below.

    1. Lead Free Means Higher Wetting Temperature

    Lead free Kester solder requires a higher temperature than those that are lead based. With its tin/silver/copper combination, this temperature is 217 degrees. This solder is no clean, an important aspect of lead free soldering since the higher temperatures required can often lead to unwanted residue.

    2. Stability of Components

    Though there are other types of lead free solder that are made with other alloys - tin-copper in particular - they have a higher melting point. This means that their wetting time is longer and it needs to be maintained for longer periods of time in order to ensure the right flow. Using Kester flux that is VOC, as well as lead free, helps ensure the balance out the high temperatures required by lead free solder.Kester 63-0004-0971 971M VOC Free No-Clean Liquid Flux

    3. Compatibility Issues

    When working with lead-free solder, ensuring that materials are compatible is imperative.This compatibility ranges from the tips used to the materials being soldered. Tips that are specifically designed to be used in lead free applications also reduce the residue, giving the finished product a cleaner look.

    Though working with lead-free solder can present challenges, they can be overcome with a few key adjustments. The benefits of a lead-free environment make the challenge of lead-free solder one to meet wholeheartedly.


  • Hand Soldering With Lead Free Materials: A How-to Guide for Beginners


    Lead FreeSoldering with lead-free materials does not need to be difficult. There are a number of tools that are designed specifically to make this job easier. When they are combined with the right techniques, a novice can enjoy an end product that is clean and residue free.

    Choose the Right Kester Solderimages (1)

    For the best results, use the appropriate alloy combination that is designed to be drawn into the wire. One such alloy is made of a tin-silver-copper combination (SAC) such as Chip Quik SMD291SNL10 Rework Solder Lead Free. This solder has a melting temperature of 217 degrees and is designed to be no clean. When compared to the other popular alloy formulation that utilize tin-copper (SnCu), this type of solder offers a quicker melting point, ensuring that it wets better and has better flow.

    KES-Pb-free-alloy-wire_27_4_1Choose the Right Wire

    To promote the proper wetting necessary to solder components together, the wire you choose needs to have at least 2% flux by weight. Using wire that has this weight allows for a good balance between wetting times and the possibility of residue. For wetting times that are deemed too slow, 3% flux can be used. However, the residue that is typically the result can be unsightly. Kester flux is specifically designed to work within lead free applications. Charring, splattering and the breakdown of the flux are minimized even when the necessary higher temperatures are used.

    Choose the Right TipSoldering tip locator

    The right tip choice makes all the difference in the delivery of the Kester solder. Lead free tips are crucial to both the success and aesthetics of the bond. These tips need to be able to deliver enough heat so that the right amount of coverage is generated. To increase the life of tips, it is important that the entire tip be designed for lead free applications. Those tips that are simply tinned with solder that is lead free tend to have a dramatically shortened life span.

    Choose the Right Technique

    Before making the final selection of flux, ensure sure that parts can be easily soldered with it. This will help reduce the desire to add excessive amounts of flux as well as the need to rework the piece repeatedly. Keeping contact times to a minimum will also result in a cleaner end product.

    Lead free soldering can result in a stable connect of materials that is also clean and residue free.



  • 10 Important Caveats When Cleaning PCBs

    PCB ImageWithout question printed circuit boards (PCBs) are extremely fragile pieces of equipment. To that end, cleaning them requires proper attention and care. Here are some mistakes to avoid when cleaning PCBs:


    1) Avoid using regular vacuums. In addition to possibly being too powerful (air-pressure wise), they may carry a charge that can be damaging in terms of ESD. Instead, use smaller units specifically designed for electronics.

    2) Use liquid detergents and water with extreme caution. Some delicate components (older crystals) may be irreparably damaged; this goes for things like labels.

    3) Use heat to dry "washed boards" only in controlled amounts. The use of an oven, for example, may be okay, as long as low heat is used and the oven is turned off when the board is put in it.

    4) Let only those persons who know what they are doing clean PCBs. This is not something to delegate to just anyone.

    5) Read up on the dos and don’ts of PCB cleaning before attempting it.

    6) Don’t be afraid to clean up sticky grime, paint, solder flux, etc. These types of debris can impair function in the long run.

    7) Corrosion (especially from battery acid) should always be cleaned up. Not doing so risks undergoing continuous damage.

    8) Take proper ESD precautions. Some people forget that ESD is still an issue when cleaning PCBs.

    9) Avail yourself of the latest products and services. Some of them may save you money and time.

    10) Don’t forget to remove any components (even if it involves de-soldering something) that may hamper the cleaning process.MicroCare mcc-frc flux cleaner



    PCBs, like everything else, do get dirty. While cleaning them can be risky (if damage is brought about), not cleaning PCBs also carries risks, especially if performance is in question, damage has already occurred (for which debris may be blamed), or debris can clearly be seen with the naked eye.


    Cleaning a PCB can be safely, conveniently and efficiently done, if you follow strict protocols and take all the necessary precautions.

  • What soldering tip do I need?

    Solder tip finding toolSoldering can be at once an incredibly rewarding and fun thing to do and a complete hassle. Without the right information, finding a tip that fits the job you are completing may be difficult. There are a few different tips that are specific to certain jobs and knowing a bit about them can make all the difference.

    Chisel Tips- chisel tips are perhaps the most common soldering tips on the market. They are easy to use, easy to come by, and are an all around great tip that fits plenty of different needs. For those just starting out, this type of tip is almost always best to get a feel for your soldering iron and your solder tip. This tip is good for creating smooth joints, smoothing over solder deposits, and more. This is truly the all around tip and should be part of any kit.

    Pointed Tips- This type of tip is almost always best for pin point work. This means that it is good for small detail work. This type of tip is good for moving the solder around after it has been deposited on the area you are going to be working with. It is perfect for creating small solders and pinpointing where you want your solder material to land and ultimately stay. This type of tip is great for both advanced and beginning users and is great for any soldering station. The Edsyn LT602-1LF tip is a fantastic pointed tip.

    Rounded Tips- these tips are great for depositing solder and for creating strong joints. This type of tip is great for beginning users and for advanced users and are perfect for depositing solder. If you are looking for a good solid soldering tip, round tips are great and offers stability in soldering for those that may not be all that sure about what they are doing.

    Mini Wave Hollow Tips- hollow tips are great for depositing solder and for moving around solder material while it is still hot and creating smooth joints. Hollow tips are great for both beginning and advanced users and are a great all around tip. Hollow tips generally feature a small well that can hold solder material at the tip to make for easy depositing.  One of the most popular Mini Wave tips is the Pace MiniWave.  Pace originated the patented tip design and we feature it on our site.  Keep in mind, the Pace MiniWave tip can only be used with the Pace soldering stations.  If you have a different soldering station brand, call (800) 521-9197 or email us for options.

    Solder tips do not have to be confusing. It takes just a bit of practice and a bit of information and you can easily and quickly find the tip that is right for your job. The tip makes all the difference and can make soldering much easier.

    Soldering tip locator







  • 10 Common Hand Soldering Mistakes

    ThinkingIdeas-150x150Proper hand soldering is an art which you can excel at only after much practice. By knowing what mistakes to avoid, though, you may make the learning/practice phases of soldering much easier. Some very common mistakes, for example, include using improper tip sizes, using a higher temperature than recommended in order to finish sooner, and not using proper ESD precautions.

    Other glaring mistakes can include:

    1. Insufficient wetting (of pad): This usually involves not properly bonding with the pad after soldering, possibly prompted by dirty circuit boards. This can be avoided by applying heat evenly both to the pad and to the pin.
    2. Insufficient wetting (of pin): This happens when not enough (if any) heat is applied to the pin, thus not allowing the solder to flow properly, creating an uneven wetting of the pad but not the pin.
    3. Inadequate wetting for surface-mounted components: The mistake involves not providing enough solder to flow unto the pad, but only unto the pin. Both the pad and pin need to be heated evenly to avoid this; the pad needs to be heated first.
    4. Disturbed joints (not same as “cold joints”): This may come about if the work is not put in a vise (when necessary)—i.e., failing to stabilize the board or immobilize the joint(s).
    5. Cold joints: This happens when the solder does not melt completely, creating a lumpy/rough surface and the use of too much solder. This can be repaired with a hot iron—i.e., by removing excess solder.
    6. Overheating of the joints: This comes about by applying the hot iron before the solder is ready to flow properly, leading to burned flux (usually causing nasty messes).
    7. Solder-starved joints: This usually involves not applying enough solder to joints, thus forming weak joints that may in time give in to stress cracks and, ultimately, malfunction.
    8. Excessive soldering: This usually leads to rounded globs over the tip and pad, often leading to lack of proper connection/adhesion. These mistakes don’t have the concave look of a properly soldered joint.
    9. Untrimmed leads: Leaving excessively long “tails” may bring about short circuits if the leads ever touch nearby traces. These leads should be trimmed at the solder joint tops.
    10. Solder bridges: This mistake involves putting so much excessive solder as to allow 2 joints to melt together (creating a “bridge). Obviously, these connections need to be fixed.


    Hand soldering isn’t easy but you can identify mistakes that you can easily avoid simply by knowing what they are and what precautions you need to take.ThinkingEngineer

  • Take Care of Your Solder Tips when Lead-Free Soldering

    Lead FreeIn the mid-2000s, many electronics manufacturers were in a panic. The European Union had mandated that most electronic products be manufactured with lead-free solder by July 1, 2006, in large part because of concern about the effect of lead in discarded printed circuit boards (PCB) on the environment. This meant that anyone who wanted to do business in the EU had to "get the lead out."

    But what can be used instead of standard tin-lead solder, which was cheap and worked well? And what are the considerations to equipment lead-free solder presents?

    One of the most widely used lead-free solders has become SAC305 tin-silver-copper (Sn-Ag-Cu), in large part because of its reduced melting point. In general, however, lead-free solders are not as reliable for mission-critical applications such as military and aerospace. And one problem that's been reported with largely tin-based solders is the formation of tin "whiskers," which can cause shorts in electronics equipment.

    The generally higher melting temperatures of lead-free solders can cause soldering tip defects and premature wear when hand soldering. This, in turn, can lead to surface contamination and nonwettability. Using Sn-Ag-Cu solder, for example, can erode the iron plating on a solder tip four to five times faster than when using traditional tin-lead solder.

    To ensure longer life of your soldering tip when hand soldering, proper care of the tip is required. Tip temperature plays a big role in durability. Using a lower temperature, when possible, can mean increased solder tip longevity. Temperature modulation tools (Auto Turn Off) within the soldering station can help you keep the heat off as much as possible.

    It's also important to clean your solder tip regularly, especially when using rosin-based flux, which is highly corrosive. Cleaning should be done with a wet sponge or brass wire sponge to remove as much flux and oxides as possible after soldering.  If conventional cleaning methods do not work, consider using a tip polisher like the Hakko FT700.  ThinkingEngineer

  • How You Can Get Solder Training

    If your soldering technique fails, your assembly will fail. Unfortunately, it may not fail immediately. Poor solder joints may hold until the PCB is installed and on its way to the consumer. The minuet speck of solder goes unnoticed until it slides under the microprocessor and fries $100 in components. Solder training can save you or your business a considerable amount of money and troubleshooting headaches.

    Large industry solutions

    Large industries can benefit from in-house solder training. A better choice is to have one or more individuals trained as instructors. Several companies, including BEST and Omni, offer IPC Master Certification training for IPC-A-610, J-STD-001 and other requirements. BEST offers a mobile program that will come to your facilities. Courses can be designed to meet your business's soldering needs from BGA Rework, SMT and Advanced SMT.

    Blackfox offers downloadable training programs for in-house training. Kits are purchased separately and include options for NASA cable assembly. Certifications for soldering must be completed through actual classes. Advanced employee preparation will improve the chances for students to receive the required certification.

    EPTAC offers in-house and eTraining programs. The eTraining programs allow participants to have audio/video interaction with an instructor from any location. Students must own a copy of the IPC or J-STD manual prior to the start of the program.

    NASA requirements can be met through IPC J-STD-001ES in addition to other IPC class certifications. A downloadable workbook is available for students working on NASA-STD-8739.3.

    Small business and hobbyists

    The downloadable classes are also an excellent choice for a small business or hobbyists. A wide range of classes are available that will help individuals improve soldering techniques. Many training companies also offer free video courses designed for improving soldering skills for those that do not need to hold a certification. Even when certification is not required, improving your soldering skills will lead to greater efficiency and better results.

  • Soldering: Tips, Tricks, Techniques & Tools To Make Life Easier - Part 3: Tricks


    When dealing with electronics for either a living or as a hobby, using a soldering iron is almost second nature. It seems like every time you turn around, you're reaching for an iron to replace a resistor or capacitor, to fix a battery lead or to install a chip. Whether you're a professional technician or the weekend hobbyist, knowing some tips and tricks to make life easier is always appreciated.

    Here are some tips and tricks that work great for either the pro or the novice:

    - Make sure your solder gauge ( diameter ) matches the connections you're trying to make. Trying to deal with a large gauge solder when soldering in a chip is a recipe for disaster. Gauges are available from 0.015 , .020" , .025" , .031" (most popular) and all the way through 0.062" which means even large gauge plugs and gang-holes can be handled properly. Kester Tin/lead Rosin Core or Lead Free is available in most gauges.

    - Keep your tip clean! This can't be stressed enough and even though it was mentioned in the last article, a clean tip keeps you in control of your bead. (And no, wiping the tip on your jeans doesn't count!). I personally recommend the brass wire sponge because it provides better tip cleaning promotes longer tip life that can be caused from thermal expansion and contraction when using a wet sponge. Having said that, the wet sponge technique has been used for years and works perfectly fine.

    - Some people will suggest using a metal file to reshape the soldering tip or remove heavy oxides from the tip. I HIGHLY recommend that you DO NOT do this. A file will quickly where down the protective metal plating and once you get to the base metal, the tip is DEAD. If heavy oxides are an issue, clean you tip more often and use a tip refurbisher for extreme cases. Also, having extra tips on hand can be a lifesaver.

    - Here's another tip that can't get stressed enough. Clean boards make clean connections so before sitting down to work on a project or a repair, use something like TechSpray cleaners and degreasers to ensure your board is ready for you to work on it.

    - When soldering, one way to make sure you get a solid connection is to; the solder across the connection by putting the tip of your soldering iron on one side of the lead and, once it's been there for a few seconds to heat it, put the tip of the solder wire on the other side. You should see the solder flow into the hole and dimple as the hole fills. Once the solder flows into the hole, draw your iron and solder up and away to create a clean finish. If you're having and issue transferring enough heat to the connection, a small amount of solder can help in transferring the needed heat. I've seen where a ground plain is really soaking up the needed heat to make the connection. When this occurs, I'll add just a little solder to make a connection between the tip and the pad. This will assist in transfering the heat. If you have a very large ground plan, I would consider a small bottom side preheater like the Hakko FR830 or one of these other options.

    - Don't work in an air flow such as in front of a fan or an air conditioner. These will chill an iron faster than you could possibly believe and even if you're using the fan for fume extraction, the air flow can cause cold solder joints and can lead to real messes on a project or a job. If you need fume extraction, which I would agree in using, look at either an economical option or a high efficiency Hakko FA430-16 ( Hakko FA430 ).

    Keep in mind that your soldering iron, whether you own a full-blown Hakko FM206 soldering station or a basic Weller GT7A soldering iron, is your key to solid connections and great projects. Taking care of it will be your first priority.


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