[Elecraft] Resistor and capacitor installation techniques: trim before or after soldering?

[Howie WA3MCK]

When I went to “mil spec soldering school” at Sanders Associates in Nashua
NH back in the 80’s we were taught to install the component and
mechanically secure it BEFORE soldering. This included clipping the leads
of resistors, capacitors, and so forth.
Why?
When you clip a component lead it creates a very small “shock wave” that
passes through the lead and on to the component. In some rare cases this
MIGHT weaken the solder joint.
Our boards were even weighed before and after assembly to estimate the
total amount of solder applied.
ALL joints were inspected under a stereoscope.
 All of this (and more) was part of the quality control and assurance
program.
This helped to reduce MTBF (mean time before failure) for our circuit
boards.
In my case I installed BRD-6/7 RDF surveillance receivers on Nuclear Attack
Boats.
Failure was not tolerated.
Howie WA3MCK

On Sat, Mar 24, 2018 at 13:29 Mark Petrovic <mspetrovic at gmail.com> wrote:

> While reading through my new K2 kit's control board assembly instructions,
> I see that some builders prefer to trim the resistor and capacitor leads
> before soldering.  I'm intrigued by this, and wonder if someone who uses
> this technique can share their experiences. Do you the solder the component
> from the top of the board or bottom?  How do you keep the component in
> place during soldering?  I am assuming the value of this technique is in
> the resulting lower profile of the components on the backside of the board.
>
> Thank you.
>
> Mark
> AE6RT
>
> --
> Mark
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