I looked into surface mount and I was taken aback about the $1000's
of dollars to get all the equipment needed.

The resisters in particular are so small they look like fly specks.
You need a binocular micro scope just to see them let alone handle
them. I decided to stick to through hole whenever possible. Some
times the PC board company charges a lot more for over 350 holes. I
decided to experiment with 1/10 watt resisters surface mounted.

The other problem is there are no markings on surface mount
resisters which makes it hard to trouble shoot mistakes in values.

I built a rig on a standard Pana Vise to hold the resister in place
with a small alligator clip while I soldered it.

This is what it looks like.

Paul Lamar


Hi Paul;

A number of vendors make boards to simplify surface mount chips:
http://www.electroboards.com/
http://www.schmartboard.com/index.asp?page=products

Fine pitch tips, soldering paste and a good soldering station go a
long way. You can get away with a large magnification loop in many
cases, although 0201 parts are still small.  0402/0603+ are easier.
Younger eyes help. I also found it helps to get different value
resistors/components from different vendors to aid visual id.

A lot of PCB companies can economically stuff your boards with pick
and place machines. Testing was way more expensive. or you can stuff
your own boards in an old toaster oven...

Cheers Cary Beazly

I did not know you were into electronics Cary. After all the years on
 the newsletter :)

Paul Lamar

Have the PCB mfg put in a full silkscreen and solder mask.

Components on one side only

Use a frying pan!

Small drop of solder (I'm building one to four boards, no stencil for a
solder mask).
Grab good ol SN/PB paste from Mouser in a syringe.  Just dot the pads.
Keep in the
fridge so the flux doesn't evaporate.  Shop fridge only -- not for food
storage.

Place component with tweezers. Nothing smaller than 0603 resistor size
on my boards.
You can scoot the part around.  Yes, they are marked with three digits
(472 = 4.7K)

Place in cast iron skillet over a single burner hot plate.  Let slowly
heat to 260C (you will see
the solder flow and wick).  Remove skillet, set to side to allow
everything to slowly cool.

Yes, I have Parkinson's so it takes me 4x as long as the "kids". Then
again I can get a board
99% good the first time.  I might have to wait for a good day to place
components.

Did I mention nothing smaller than 0603 sized parts!

Tom Walter



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