[Elecraft] OT: Another quick question about solder...

[Paul Christensen]

> Anyway, I'm about to nervously perform the VFO noise mod and jumper mod to
> my K3.  I'm not looking forward to it.  I have soldered other things
> together like the repair work on my SB-220, but I've never been happy with
> the quality of my solder.

Practicing on a scrap PC board with "vias" may instill some confidence in 
the job.  Ensure that the work area is well-lighted, and you're using a 
solder station of reasonably good quality.  Depending on your degree of risk 
aversion, you may also want to consider the use of an anti-static mat.  If 
the budget allows, purchase one with an adjustable, temperature-controlled 
tip.  Either a conical or very narrow chiseled tip will work well.  Be 
mindful of the tip temperature and clean the tip often on the wetted sponge. 
For wicking and extraction purposes, I generally set the tip temperature 
between 750-800 degrees F -- and 700 degrees F for general soldering.  For 
use with 2% silver bearing solder, I inch the tip temperature up just a bit.

When you're ready to proceed, you may find that one or more vias as 
described in the Application Notes may be filled with solder.   I first 
attempted to wick the solder by adding slightly more solder onto the via --  
and also tried using a Soldapult.  However, the diameter of the via is quite 
small -- nearly the exact diameter of the component lead.  Rather than risk 
PCB damage, I pre-cut the component lengths, added a slight amount of solder 
to the via, then gently inserted the component's lead into the via while 
keeping it hot with the soldering tip.  That worked very well, although I'm 
sure others will have suggestions for clearing out a via without the need 
for an expensive re-work station.

Moving on to the "K3 Extreme Signal Rx Protection Mod," I used #26 Kynar 
(i.e., wire wrap) wire between the via and  component pad.  A hot glue gun 
was then used to dab glue at the wire bend locations as shown in the 
Application Note photos.  This makes for an easy, fast and 
professional-looking way of securing the wire onto the PCB.

Paul, W9AC