PAIA & kits - ametuer

[Bill Layer]

Hi Leon,

>> 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.
>> 
>
>On the printed side, I am assuming?  Does that apply to jumpers as well?

To clear this up, I mean leave a little leadlength the component side.
>
>> 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.
>> 
>
>I have one or two points where the solder is beaded, but the lead coming
>out of the board at those points just barely poked its head out.  I
>figured that it beaded b/c there was not enough lead for the solder to
>"cone" around.  It seems like a solid connection.  Should I redo it? 

Yeah, that happens. The term is "uninspectable joint", and they are not
allowed in high-spec builds (military, medical, etc.) If I'm concerned, I
usually de-solder the joint and inspect it to see where the solder had
been. If it looks wet all over, I just re-solder it. 

>Also, is production equipment really hand-soldered?

handwired stuff from the tube era, yes for sure. Most PCB stuff post 1969,
no. But wave solderers make beautiful joints; you should strive for that
level of consistency.
>
>> 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.
>> 
>
>This is about how I am doing it, the solder drops very fast once the
>component is hot and I just try to guide it in and pull the elements
>away.  I would say that this takes just a couple of seconds like you
>mentioned.

Good! A properly flowing joint will seem to drink up solder like a sponge,
especially on plated-thru hole boards. 


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

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