Ensure that you have no distractions!
- A good quality fine point soldering iron (temperature controlled workstation is best)
- Good quality, low melting point, fluxed solder (Lead/Tin if you can get it)
- Tweezers - I used a metal healthcare set - eyebrow plucking tweezers are probably not a good idea as they are small and fiddly and too stiff. They need to be comfortable in your hand and not require force
- Glass bowl with high sides - I used a glass ramekin
- White cloth - I used kitchen towel - This helps visibility and suppresses bouncing if the SMDs are dropped! Place it under the bowl and under the PCB
- Magnifier - I used a head mounted magnifier with a loupe
- Lots of light!
- Identify the value to solder and highlight with a circle on the drawing where each one goes
- Tin one pad of each location on the PCB - do not use too much solder
- Carefully expose the SMDs over the bowl by pulling back the top film with the tweezers. Allow them to drop into the bowl from a low height - The white cloth under the bowl helps to make them visible
- Any SMDs that are face down can be lifted with the tweezers and dropped, they will flip over without 'man-handling' them as they bounce
- Count them!
- Orient the PCB so that soldering will be easy
- Using the tweezers, transfer one SMD to the board, the silver ends line up with the pads
- Place the tweezers on top of the SMD do not apply force, if you slip, the SMD will never be seen again! The SMDs are so small that capillary action will cause them to stick to the iron tip; this is why we want to hold the SMD down
- Apply heat to the junction of the tinned pad and the SMD, when the solder wicks, remove the heat but keep holding the SMD until the solder solidifies.
- Rotate the PCB 180 degrees
- Apply heat to the junction of the pad and the SMD, apply a small amount of solder to the junction. Be quick as the heat will transfer and unsolder the other pad
- Allow the solder to solidify
- Inspect the joint with the magnifying glass, resolder if you are not happy. If still not happy, come back to it later
- Mark off the circle on the drawing
- Pat yourself on the back before moving onto the next
- Take your time and relax