TITLE: Basics of soldering
AUTHORS: Eric S McLamore

[DESCRIPTION]
This protocol describes the basic principles of soldering. An ANBES soldering station is used for this protocol, but most of the methods are interchangeable with other soldering irons. The process requires approximately 30 min, but timing can vary depending on the number/type of components which require soldering. A list of useful references is provided for further reading.

[BEFORE_START]
Be careful when using soldering iron as it can heat up to 896 °F 
Additional resources and more information are available at the following links:
MakerSpaces Soldering guide (link here)

 


[STEPS]
SECTION: Prepare equipment and materials
1. Wet sponge with DI water and place in soldering iron stand
If using a brass sponge it is not necessary to wet with DI water
Ensure that soldering iron stand is properly positioned (Fig 1)

 

 

Inspect the soldering iron tip. The tip should be free of physical bends/scrapes, glue, or other damage
Check soldering iron tip to ensure it is secure (hand tighten threaded rod if necessary) (Fig 2)

 
Ensure ample tabletop space (or chemical hood space) is available for soldering
Arrange materials to be soldered near the soldering iron station (e.g., in the chemical hood)
SECTION: Prepare equipment and materials
2. Tin the tip 
Turn on the soldering iron
If using an adjustable temperature solder station, set the temperature to 400C
Wipe the tip of the soldering iron on the wet solder sponge 
Rotate it back and forth and wipe it at least three times on the surface
Wait 10-15 seconds to let the tip heat up again 
Hold the soldering iron in one hand and solder in the other. 
Touch the solder to the tip of the iron and make sure the solder flows evenly around the tip.
The tip is now “tinned” and ready to use

 

SECTION: Prepare equipment and materials
3. Insert components, or arrange as needed 
If working on a circuit board, mount the component to be soldered by placing metal pins into circuit board holes. Then flip the board and bend the metal pins at a 45 degree angle
If a different arrangement/geometry is required, position the items to be soldered next to each other so that they are touching and stable 
 

SECTION: Prepare equipment and materials
4. Heat joint where solder is to be applied 
Using a tinned soldering iron that is preheated to 400C, touch the tip of the iron to the joint 
Hold the iron in place for at least 5-10 seconds to heat the joint and any components

 

SECTION: Prepare equipment and materials
5. Apply solder to joint 
While continuing to hold the soldering iron on joint, touch the solder to the joint. 

 

After the solder melts, carefully pull the soldering iron from the tip and place in the stand
Wait at least 10-20 seconds after step 5,

 

SECTION: Prepare equipment and materials
6. Strip excess solder from leads 
A proper solder joint is smooth, shiny and has a cone shape. 
The amount of solder should be sufficient to cover the joint, but not overlap with nearby components
Remove any excess material from the joint with anti-static tweezers

 

SECTION: Prepare equipment and materials
7. Clean up laboratory 
Turn off all equipment
After the soldering iron has cooled, clean the tip using a stainless steel sponge
After removing debris, clean the tip with a cloth dipped in 70% alcohol 
Clean workstation/benchtop
Dispose of all materials per hazard/warning section