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    Lead Free Solder Bar: How to avoid mistakes during welding?


    Cold solder, have you ever heard that term? You know what it is?

    Lead Free Solder Bar

    Do you know when you finish a weld and the appearance doesn't look good? Is it uneven, rigid, does the point seem unreliable at all? Yes, you may have made a lead free solder bar.

    The Weld Cold is a defect generated at the time you do the welding. It occurs due to several factors, which we will present here for you.

    The term is very common and it is very easy to happen. But it is easy to detect and also easy to resolve. Stay tuned and have a great read!


    We already have an article on soldering here on our blog , but let's remember a little.

    The welding is a method of forming electrical and mechanical connections on a printed circuit board (PCB) by connecting electronic components to the board through lead and tin alloy castings. (Can be lead free too)

    Welding is usually done using a soldering station or a soldering iron and a soldering wire (tin and lead alloy).

    How do you weld?

    Welding is an essential part of all electrical and electronic engineering, especially electronics. You need to make excellent welds at ALL points on your circuit for them to work in harmony.

    Have you ever imagined lead free solder bar a plate with hundreds of points and your circuit fails, because there is a problem solders point?

    Okay, but how is the ideal weld?

    Come with us and see how the ideal lead free solder bar should be.


    A solder point is just a specific solder point to interconnect an electronic component to the PCB and give it a reliable mechanical fixation.

    A cross section of an ideal weld joint should have:

    • A concave melted solder;
    • The solder must be smooth and shine

    The illustration below shows the ideal weld. See, the weld has to get wet; it has to flow perfectly in harmony with the joint.

    Some secrets to attain welding skills

    Now, let us tell you a SECRETGood welding is an acquired skill that requires a lot of practice. You will only have excellent welds if you practice, practice and practice. And even if you practice a lot, you will never be totally error free. Sorry if you are disappointed, but it is pure reality.

    So, every minute you are lead free solder bar a component, you have a chance to do better than before. What if I miss? You will learn from the mistake and the next time you will do better.

    Tip to remove the solder

    Tip: Take a scrap board, with several components, where you will not have any damage and remove the components and solder again. Do this several times! If you have any questions, check out our welding classes , it costs nothing.


    In this article we will focus on cold welding, but it is worth highlighting some problems that can happen in your day-to-day:

    You can make several mistakes during the welding process and it is good to be prepared! Below are some of the most common errors:

    • Cold Welding : Welding that does not melt completely before welding;
    • Overheated spot: Occurs when the solder wire does not melt despite heating. This action results in the overheating of the flux in the plate, which, in turn, complicates Lead free solder bar.
    • Insufficient wetting: This problem occurs with the pin or the plate. It is an indication of heating the weld unevenly on the plate and pin. Improper moistening of the pin shows that you burned it more than the plate. Inadequate wetting of the plate, on the other hand, may indicate the application of little damp material.

    Mistakes to avoid during welding

    You may have other problems with welding due to inadequate solder tips, loss of wettability, improper plate cleaning, etc. But as we said earlier, today we’re going to focus on Lead free solder bar.

    Without further ado, you already know what welding is, how it has to be the ideal weld and some of the most common problems that you will encounter in the welding world.


    The welding Cold is a problem of the weld joint which typically occurs during welding.

    It happens when the solder fails to melt completely and it does not flow correctly at the connection points, not forming an ideal solder point.

    This failure can arise when you do not properly heat the lead free solder bar wire before welding. In some cases, it can also arise if you disturb the welded plate or pin before the melted solder solidifies.

    Problems in cold welding

    The Weld Cold usually has an opaque appearance and makes the convex mounting on pins and flexible areas of the board.

    Sometimes, they also take irregular shapes, like the image below: I don't even have to tell you that this solder is far from ideal, right?


    Now that you know what cold soldering is, here are some causes below:

    • Low component wettability (subject for the year 2020 still, follow us!)
    • Inadequate welding parameter: welding temperature (too high or too low, welding time, too thick or too thin tips, etc.)
    • Solder pollution (contaminated alloy)
    • Mechanical stress
    • Poor weld fillet in the through / wetting hole
    • Contamination of surfaces to be adhered
    • Inadequate component geometry and vibration, causing joint damage
    • Among the most common causes of cold welding are disturbances such as vibrations during the welding cooling period.Lead Free Solder Bar 2021


    Here are the characteristics of the lead free solder bar to help you detect:

    • Rigid, rough and uneven appearance
    • An unreliable joint
    • Highly susceptible to cracking and failure

    If you finish your welding process and find the spot in some way mentioned above, redo it!


    It is very important that you analyze your board very well after welding. It is essential that your weld is 100%.


    Did the welding, analyze. Check! If you need to redo, redo. Your customer trusts you. There will be many cases where the solder will not come out with good quality. On these occasions, it is recommended to remove everything and start work again.

    The lead free solder bar is more common than you might think. Several times we receive situations like this.

    Points to remember

    You learned in this article:

    • What is soldering (a brief summary)
    • The ideal welding point
    • Common welding problems
    • What is Cold Welding?
    • Causes of Cold Welding
    • Cold Solder Features
    • Testing cold weld

    Make excellent welds!

    Be careful not to put too much solder and cause short circuits. If you find that you have added too much solder, remove the solder with a sucker and do it all over again.

    Take care as some components can be damaged if they get too hot during the welding process. To prevent this from happening try to weld quickly so that the component does not receive too much heat from the soldering iron.


    You need to make mistakes, analyze the error and always correct them so that you can be better. In welding, only with the error will you create a vast experience. Always practice. Don’t be in a hurry to weld. Lead free solder bar is a practice that requires patience, tranquility.

    For beginners, a good alternative is to train the welding procedure on old devices, which no longer work. After a few attempts, welding will become very natural for you through Lead free solder bar. Over time you will master the technique and ensure that your projects are perfect.

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