Common Soldering Problems: Overheated Joint

What is an overheated joint?

Overheated Joint

An overheated joint is an issue in soldering that is faced by many. An overheated joint is identified by its distinctive bulging, being whitish and charred marks around. 

How is an overheated joint formed?

As you would expect, an overheated joint is formed by being…overheated! Usually from the soldering iron’s temperature being too high, being exposed to the soldering irons' heat for too long or possibly due to the surface having leftover oxide. 

How to prevent an overheated joint?

  • Keep your soldering iron clean. Soldering tips with residues and build ups at the tips prevent an efficient flow of heat transfer. It may also cause the user to solder at a higher temperature in order to melt the solder properly. This may result in easier burning of the joint as a higher-than-normal temperature was used. By keeping your soldering tips clean, and removing excess residue, you can easily prevent overheating the joints. Use the FS-210 Brush Tip Flux Pen to clean dirty and spotty areas on joints or pads.


  • Understand the correct temperature for your joint. With different material conducting heat differently, one needs to understand the material to prevent overheating of the joint. Lead and Lead-free solder wire also melt at different temperatures due to the difference in melting points. 


  • Look out for discoloration. Discoloration on a joint is a sign of overheating, to prevent severe damages and cost, it is imperative to constantly have an eye out for the color of the joint.


  • Avoid holding the soldering iron to the board for too long. Keeping the soldering tip against the board for too long even after the solder has melted will cause the heat to transfer to the board and overheat the joints. 


  • Select the right tip shape and size for your joint. Tip shapes that are too big brings excess heat to the joint, while tip sizes too small will not be as efficient to heat up the joint, causing the user to hold the heated tip against the joint for a longer time. Both situations can cause the joint to overheat. 

How to fix an overheated joint?

  • Remove the burnt areas/flux. This can be done by scraping the overheated joint using the tip of a knife.
  • Alternatively, use isopropyl alcohol and brush the burnt flux off.

12 most common soldering problems (and how to fix them):

  1. Cold Joint
  2. Disturbed Joint
  3. Overheated Joint
  4. Insufficient Wetting of the Surface Mount
  5. Insufficient Wetting of the Pad
  6. Insufficient Wetting of the Pin
  7. Solder Starved
  8. Too Much Solder
  9. Untrimmed Leads
  10. Solder Bridge
  11. Lifted Pad
  12. Stray Solder
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