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

[Don Wilhelm]

Mark,

It is usual for most components to mount on the top side of the board 
and solder from the bottom.  Splay the leads slightly to keep the 
components from falling out when you turn the board over.

For components mounted on the bottom side of the board, I normally put 
them in the same way, and I will choose whether to solder them from the 
side the component is mounted on, or if there is enough space on the top 
of the board to solder from the top side without endangering the already 
mounted components on that side, I will solder from the bottom.

With resistors and inductors, it is easy to solder on the side they are 
mounted, but with many capacitors that is not possible because the 
solder pads and capacitor pins are obscured by the component body.

To pre-trim the leads and solder on the same side as the component can 
be difficult at times.
Mounting components without pre-trimming the leads can be troublesome in 
some areas where components are already mounted on the other side.  You 
need flush trimmers with a "nose" that will reach the lead to be cut 
betwen already mounted components.
If you determine that you will not be able to trim the leads easily, 
then pre-trim the leads and solder from the same side as the component.

Generally, there is only a need to pre-trim in selected areas.

The KSB2 option is one of the option boards where you might want to 
consider pre-trimming the leads of the resistors mounted on the bottom 
of the board.

73,
Don W3FPR


On 3/24/2018 1:28 PM, Mark Petrovic 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
>