What are the common problems in soldering? (2023)

Soldering is a technique that is widely used in electronics, and various other industries to join metal together and create electrical connections. However, several common issues can arise during soldering, which can result in weak joints, poor electrical connections, or even component damage.

Some common problems in soldering are disturbed joints, cold joints, solder bridges, untrimmed leads, solder-starved joints, overheating joints, poor wetting, tombstones, lifted pads, and solder splashes may arise while you’re doing the soldering.

This article explores some common problems encountered during soldering and offers insights into how to overcome them effectively.

Table of Contents

Common problems in soldering and how to overcome them

Soldering is an essential skill but due to our negligence or wanting to do work quickly, improper tools, there are some common that may arise and will affect the effectiveness of electrical joints. By identifying and understanding these problems you will be able to overcome them.

Let’s discuss the common problems in soldering.

1. Disturbed joint

One of the most common mistakes is disturbed joints. When you apply solder to a joint, it is important to leave the molten solder to solidify, otherwise due to movement or disturbance while the solder is still molten can result in what’s known as a “dry joint,” where the solder doesn’t properly bond with the surfaces.

Disturbing a joint early can lead to weak connections or failure with time. Allow the solder to cool naturally, and if you need to move the components, do so gently and avoid any sudden motions. Try to keep the joint still until it solidifies completely.

In some cases, this issue can be corrected by reheating the joint and allowing it to cool down without any further disturbance.

2. Cold joint

A cold joint refers to an undesirable outcome that can occur during the soldering process, where the soldered connection doesn’t form properly due to inadequate heat transfer. Cold joints appear rough, dull, and uneven.

This is the problem when the solder fails to achieve a sufficient molten state during soldering. Cold joints make weak connections that lack bonding ability and with time there is the risk that it will crack or break.

Cold joint can be corrected in some situations like you reheat the joint. Apply hot iron to the joint until the solder melts and creates a shiny and strong connection. If the joint has excess solder you can remove it using the tip of a soldering iron.

Also, make sure your soldering iron tip is clean because dirt accumulated on the tip also reduces the flow of heat from the iron to the joints. To enhance solder flow and create reliable joints use the right amount of heat and flux.

3. Solder bridge

Another problem is the solder bridge that occurs due to applying excess solder. When two distinct joints melt together, a solder bridge forms. This is due to too much solder so the joint appears round and swelled.

Solder bridges lead to short circuits and malfunction of electrical connections. To fix this issue you need to remove excess solder and cut the joint to a proper shape, separating the unintentionally created joint. Heat the soldering iron and trim down the extra solder.

Altering separating joints correct their shape by using a soldering iron. Also, use the appropriate soldering iron tip to reduce the risk of solder bridge and excess solder application.

4. Untrimmed leads

Untrimmed leads are one of the most dangerous problems in soldering joints. These untrimmed leads are the length of wire that is left over after inserting it into the circuit board. It sticks out and can be seen with the naked eye.

A short circuit can occur if these untrimmed leads come in contact with each. Because leads are longer, they can easily bend over time and come into contact.

Untrimmed leads can be trimmed by using appropriate tools. Take the trimming tool that you are using during soldering and cut down the leads up to the desired length.

5. Solder-starved joints

Solder-starved joints mean the joints don’t have the desired level of solder. Applying too less amount of solder to joints can also create problems like weak joints, joints could crack down, and lead to overall poor performance of soldering.

To solve this issue reheat the joint and apply the appropriate amount of solder to create a strong connection. The joint is now able to handle stress for long periods.

6. Overheating joints

Applying the correct temperature or heat in soldering is a crucial step. If a high temperature is applied to the joint it will overheat the joints which will lead to damage to components.

Applying low heat can not melt the solder to its melting point and will create cold joints. Cold joints are weak and crack down easily. Use a soldering iron with a temperature control feature to set the temperature according to your need.

7. Insufficient wetting

Wetting means the flow of solder and insufficient wetting refers to the incomplete spreading of solder across the surface to be joined. Wetting property is affected by contamination or dirt on the surface, pad or pin. If proper heat is not applied to the pad and surface this will also lead to poor wetting.

With the help of a soldering iron heat the pad before applying solder and make sure you use flux which cleans the oxidation from the surface and enhances the flow of solder to create strong and reliable soldering joints.

8. Tombstones

Tombstones occur when you want to solder the components like resistors, capacitors, and transistors. If it is correctly soldered with the pad, the components will be straight.

If the appropriate temperature is not provided during soldering it will cause the lifting of one or more sides of the component, creating a tombstone-like appearance. It affects the soldering joint which leads to degradation of the overall performance of PCB.

9. Lifted pads

Aside from any issues with the joints, you may detect locations where the solder pad separates from the circuit board. A raised pad may appear if you have overworked a joint or given the solder many sessions with a hot iron.

This problem is very common with boards as the copper layer is thin. It generally happens due to repeated or excess stress on the board. The repairing process of lifted pads is very risky.

10. Solder splashes

Solder splashes, often an unwelcome outcome in the soldering process, refer to small droplets of molten solder that unintentionally scatter and disperse during soldering.

This occurs due to excess solder, rapid movement of soldering iron, and contamination of the board. This will lead to different issues such as contamination of nearby components, short circuits, or even a burn if it comes in contact with the skin.

Proper cleaning and use of flux can minimize the solder splashes.

Conclusion

Soldering is a valuable skill that requires attention to detail and proper technique to achieve reliable and durable connections. By understanding the common soldering problems, you will be able to create strong joints and reliable electrical connections.

The most common problems in soldering are disturbed joints, cold joints, solder bridges, untrimmed leads, solder-starved joints, overheating joints, poor wetting, tombstones, lifted pads, and solder splashes. These problems need proper handling.

Try not to disturb the molten joint, apply the right amount of heat and solder to the joint, and make sure you use flux to enhance wetting and clean the contamination from the surface being soldered and from the soldering iron tip.

Choose the right tools, maintain good soldering habits, and practice regularly to improve your soldering skills over time.