PAIA & kits - ametuer

[Bill Layer]

Hi Leon,
 
>My question is this:  b/c the soldering points are so close, I wonder if
>anyone can describe to me what a good solder joint looks like.  This is
>a lot more precise than wiring racks or making cables, and I just would
>like to know if my joints are as clean as they should be.  Should the
>solder point be a round bead?  Should the lead extend past the end of
>the solder joint?  How much lead in general is good to have sticking out
>the back of the PCB?  What are some common pitfalls?  Except where
>noted, I am assuming that all the components should be basically flush
>against the board.

Not too flush against the board; if leads are too tight, thermal cycling
may cause stress on the part. Best to leave 1/16 or so of lead.

If you want to know what good solder joints look like, open a piece of
existing equipment and examine it. If the solder appears like a round bead,
that means that it hasn't flowed onto the PCB surface. Surface tension of
the molten solder tends to hold the bead shape.

Remember: Heat the joint with a clean, tinned iron. When the joint is hot
enough, add solder to the joint (NOT the irons's tip!) and watch it spread
quickly to both the pcb and the part. A good, swiftly made joint should
almost 'flash' as the solder wicks into it.

Keep in mind, that each of the joints on the fatman pcb should be made in
about 2 secs. If it's consistently taking longer, your iron is not properly
cleaned and tinned, or your technique is faulty.

Good luck! 
Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

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