Common Soldering Problems: Stray Solder

What is Stray Solder?


Stray Solder are tiny solder fragments leftover on the board in places where the solder is not meant to be due to the sticky flux residue, wrong soldering techniques, or oversight. While it may seem harmless, these stray fragments of solder could cause electrical short circuits causing the board to malfunction.

How is Stray Solder Formed?

As stray solder is a term for solder that do not belong, it can be formed by the following:

Solder Bridges
When two points on a circuit board is connected by the solder over the top of the PCB

Solder Balls
Tiny droplets of solder that splash off the tip of the solder iron on surface of circuit board

Solder Wicking
When solder applied flows up the lead components on the circuit board


Insufficient Cleaning
If circuit board is not cleaned properly after soldering, excess solder can remain on the surface


How to prevent Stray Solder?

It can be prevented through:

  • Applying the right amount of solder to the components
  • Clean the circuit board before and after soldering
  • Remove excess solder

How to fix Stray Solder?

Simply use a knife or a tweezer to carefully scrap and remove the stray solder bits and ensure there are no remaining excess or stray solder on the board before using.

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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