Extreme soldering

A steady hand is not optional with hand assembly of surface mount design

Hand surface mount prototyping

This is not the smallest part – there is a much smaller thermistor below.

0805 chip resistor
The ball point pen points to the part.

Sneezing is not a good idea.


I did my best to take a picture through the eye piece of the scope. R3 is the same resistor placed ready for me to solder.

It is easy to bump the part out of alignment – small steady motions – sometimes the surface tension of the solder causes ‘tombstone-ing’ where the part stands up on one end.

Once this is all assembled, these will normally be put together by robots – the solder is applied via stencils and then into a infrared oven to melt the solder.


I installed a 0204 thermistor tonight – by far the smallest part I’ve ever soldered. On the first attempt, the surface tension of the solder just picked it up and stuck it to the soldering iron. I re-positioned it and then carefully laid a tiny corner of a circuit board on to to hold it in place. I don’t really need one this small, except it is the only one that is thin enough to match the FETs I’m using.  It is the speck in the red circle –  (not the best picture)

Small enough?

Small enough that just breathing moves it around – I had to be careful to breath slowly..

Any smaller and it would be dust!

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