[Elecraft] K2 build question

[Don Wilhelm]

Mike,

It is not necessary to clean the component side to get nasty stuff in 
the components.  If one floods or sprays the board, some of the cleaner 
can and will wick to the component side through the via holes and other 
openings.  Having a mixture of flux and cleaner coated all over 
everything can create a worse mess than what one started with - alcohol 
attracts water out of the air, and the combination of moisture trapped 
with flux residue can indeed create problems down the road.

That being said, and before someone asks, yes I sometimes do clean the 
flux off, particularly in an area that has received a lot of rework and 
the buildup really gets nasty.  On some of the boards that have been 
sent to me for repair, there is so much excess solder and flux residue 
that I have no choice but to first get out my Hakko 808 and suck off 
much of the solder, then clean the board and re-solder everything.  That 
is the extreme, but it does happen. 

The problem seems to be that some builders go back to the old days when 
soldering tube sockets with a soldering gun and applying lots of solder 
was the way to do it, but those days are gone and different techniques 
must be used - with thru-plated holes, just enough solder to fill the 
hole is sufficient.  Check out the soldering tutorial on the Elecraft 
website if you have any questions about what a good solder connection 
should look like.

I cannot judge everyone's experience or skill level, so I must make 
suggestions for the lowest common denominator - If you know what you are 
doing, work carefully, and observe the precautions, then you can remove 
flux, but if not, either avoid it or gain experience on something 
inexpensive rather than your new K2.

73,
Don W3FPR
 

Michael Harvey wrote:
> I can agree with that, Don, but rarely have I seen anyone clean the component side of the board. Since the crystals are on that side, and they were described as being soldered prior to installation, I saw no harm in recommending cleaning the flux off. I don't remember any relays located around the crystals. Just a torid that it may effect if excessive alcohol is used.
>