Reasons Why Your Soldering Won't Stick

6 Top Reasons Why Your Soldering Won’t Stick

Soldering is a popular method for joining metals together. The process utilizes an iron rod to heat up solder (metal alloy filler), which then flows into the joint and bonds metal pieces together. In a typical soldering process, this is supposed to happen seamlessly. However, the solder won’t stick and form a strong bond in some instances. Why does this happen? Well, there are several Reasons Why Your Soldering Won’t Stick. Here are the most notable reasons and what should be done about it.

6 Top Reasons Why Your Soldering Won’t Stick

I. Oxidized Soldering Iron Tip

A soldering iron plays a critical role in the soldering process. If the iron tip is dirty, this may interfere with the final bond. Oxidized soldering iron tips aren’t great conductors of heat. In most cases, an oxidized tip may fail to become hot enough. In such cases, the soldering iron can fail to melt solder.

Oxidation is a common problem when the soldering iron isn’t stored properly. Also, a soldering iron tip should be cleaned after use and covered before being storage. If the tip is stored openly while dirty for long periods, it is bound to get oxidized.


To resolve this problem, the tip should be cleaned accordingly. Cleaning must follow certain procedures to offer a perfect outcome. For instance, the soldering iron should be heated to a typical working temperature (approximately 300 degrees Celsius) before flux-colored solder is applied to the tip. The resulting chemical reaction (when the flux is activated by heat) will result in a chemical reaction that eliminates oxidation. Some specialized cleaners or brass wool can be used in the process to eliminate the oxidation completely.

Preventing Oxidation

Besides storing your soldering iron properly, as stated above, the soldering iron tip should also be coated with some solder to avoid direct exposure to air when the iron isn’t being used. What’s more, the solder should coat the tip completely. The process should also be done at a working temperature (approximately 300 degrees Celsius) to minimize exposure to air.

II. Oxidation or Dirt on Work Pieces

Besides the tip, oxidation on workpieces can also stop the soldering from sticking. The metals being joined should be clean and free of oxidation. Otherwise, the final soldering joint won’t adhere properly.


When joining two metal workpieces together, clean the metals first. This applies mostly to old metal pieces, which tend to have a thick layer of dirt. Old parts are also bound to be oxidized given their prolonged exposure to aid. Besides cleaning the workpieces, a strong flux should be used to clean the workpieces effectively. Workpieces made of copper which are more prone to oxidation can be cleaned effectively using erasers. Light sanding should remove dirt and oxidation effectively before soldering.

Preventing Oxidation of Workpieces

To ensure your metal workpieces don’t oxidize and accumulate dirt, store them appropriately. While oxidation may be inevitable for metals like copper exposed to air for a long time, constant cleaning can help i.e., once every week or two. It can also help covering the copper and storing it in a dry place. Copper, unlike other metals demands more care to stay in perfect condition for soldering.

III. Corroded Wire

Your soldering can also fail to stick because you have electrical issues. Electrical soldering isn’t just about the soldering iron tip. The metal wire also matters. Soldering irons can accumulate dirt on the wire you are working with, stopping it from holding properly.


Applying some flux can help. However, if the wire in question is copper, some mild sanding can help. This is the case since copper oxidizes faster than other metals.

Preventing Corrosion

Some prevention measures can avoid this problem. For instance, cleaning work materials after use and storing them properly is a simple and effective prevention measure. While aging materials will still be prone to problems, paying more attention can help avoid corrosion and related issues that prevent soldering from sticking

IV. Low Solder Temperature

Solder can also fail to stick because it isn’t hot enough. In most cases, this issue can be traced back to soldering iron problems. If the iron isn’t set to the ideal temperature, it won’t be able to melt the solder adequately. What’s more, the soldering iron wattage may be too low to heat the solder size in question.


Small soldering chips should be melted using 25 to 30-watt soldering irons. This is ideal for typical soldering applications such as soldering connectors.

Preventing Solder Temperature Problems

As mentioned, it helps to use the right soldering iron (wattage) for the right solder. A simple comparison between the soldering material you are using and your soldering iron wattage should help you determine if your solder will be heated appropriately. If your soldering iron cannot get the job done, switch to a higher-wattage solder.

It also helps to understand the job at hand and what you need to succeed. Before buying large soldering wires, ensure you have a soldering iron for the job. Larger soldering wires can’t be heated appropriately by typical soldering irons with a 25 to 30 wattage.

V. Low Metal Temperature

The metal temperature could also be to blame. In some applications, the metal should be heated as well to a specific temperature to ensure the solder sticks.


As mentioned above, not all soldering applications require the metals being joined to be heated in advance. If heating is required, you need to ensure the soldering tip rests on the metal pieces in question when heating the solder. This should make the metal surface and the solder hot enough to stick together.

Preventing Low Metal Temperature Problems

It is possible to heat the metal pieces to the required temperature by simply initiating contact between the metal and soldering iron for a prolonged period. Doing this should heat the metal to an ideal temperature. You can use other heating aids such as a propane torch to get the metal to the perfect temperature. Your heating choice should be determined by the metal type and size.

It also helps to heat the metal properly before you attempt to solder. The general requirements should also be in mind. For instance, a small metal piece can be heated by a small-wattage soldering iron. Larger metal pieces may require higher wattage irons or a propane torch. They also require more time to reach the perfect temperature.

VI. Poor Soldering Techniques

Poor technique is also among the reasons why your soldering won’t stick. There is a good and bad way to solder. Contrary to popular opinion, soldering isn’t just about melting solder with a soldering iron and directing it to the joint. You can burn the flux from your solder if you simply let the solder “sit” on the soldering iron and “carry it” to the joint.


Flux is critical for eliminating oxidation. Since oxidation hinders effective soldering, it’s good practice to avoid burning off the flux when soldering.

Preventing Poor Soldering Techniques

Solder should flow to the joint immediately after it melts. Allowing the solder to “sit” on the iron will burn the flux. It can also make the molten solder to fall off. Other poor techniques include soldering with an oxidized soldering iron. You need to clean your soldering equipment after use. The equipment should also be stored properly. If you do this and learn good soldering techniques, your soldering process should be seamless.

VII. Other Reasons

Other Reasons Why Your Soldering Won’t Stick include soldering with untrimmed leads. Once you have soldered your joint, you should create a lead or small stem jutting from the joint. However, the leads shouldn’t cross or join, or you risk compromising the connection, especially in electrical applications. Leads should be a perfect size, or you risk dislocating the joint. To avoid this, you should trim leads so that they aren’t above the joint.

Insufficient wetting is also a problem, especially in electrical soldering applications. Learning proper soldering techniques should help to avoid this problem.

Under-soldering a joint can also prevent soldering from sticking properly. In fact, this problem is a leading cause of unstable or weak joints. You should use as much solder as required to support the joint in question. The precise amount should be dictated by the size of the joint and the metals in question. Ideally, the solder should cover the entire joint. What’s more, the joint and metal should be heated adequately before more solder is added.

Disturbing the joint can also prevent proper adherence. Ideally, the workpieces should be secured in place first before soldering. Moving the workpieces when soldering can prevent sticking. The joint should be left for some time after soldering just to ensure the solder dries up and holds the metal pieces in question perfectly. This may require other remedies, such as stabilizing the workstation.

While there may be other Reasons Why Your Soldering Won’t Stick, the above information covers the most common reasons and what you should do to address or prevent the problem.