Tips for soldering switches without melting them

While there are various types of switch terminals, one of the most common forms used in pedal-building is the solder-lug terminal found on panel-mount electromechanical switches.

 

But how do you solder them?

When a switch has solder lugs, they are typically located on its underside, where wire is soldered to the lugs to create a solid, conductive connection. This method forms a permanent bond between the switch and the wire, making solder-lug terminals one of the most reliable solutions, even for high-current loads.

In these switches, the solder lugs are surrounded by plastic, which is prone to melting if overheated—especially in cheaper switches. If the plastic melts, it can shorten the switch’s lifespan or even render the switch unusable.

 

Tips for soldering without damaging them:

• Use a soldering iron that can be set to the desired temperature. 
• Tin the wires before attaching them to the switch’s lugs. 
• Use a no-clean flux if necessary. 
• ALWAYS check the switch’s datasheet provided by the manufacturer for information on the soldering heat resistance of the plastic. A typical specification for small toggle switches is often listed as follows:

- Maximum soldering temperature: 250 °C
- Immersion time: 3  seconds
- Maximum soldering frequency: 2 times
 

• While the above specs is just an example, it applies to a lot of switches out there. If you can't find the datasheet of the switch you have on your hands, use the above specs as a starting point.
• Soldering times and temperatures should not exceed the recommended ranges specified for each switch. Do not operate the switch during or immediately after soldering—wait at least 2 minutes.
•  If you messed up a soldering, don’t try to fix it right away—wait at least 5 minutes for the switch to cool.

> While the next tip is usually unnecessary for pedals, I’m including it for anyone who might find it useful elsewhere, especially when high voltages are involved:

• You can’t always add shrink tubing, but covering the solder joint with it helps protect against debris that could cause corrosion and also reduces strain. Adding an epoxy seal to the bottom of the switch is another way to provide extra protection. 

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