[Elecraft] K2 - Cleaning a completed PC board

[OZ2BRN Brian Lodahl]

  Hi Stan WB2LQF,

IN the event that you may decide to do an isolated cleaning of some area 
of flux that is particularly nasty, then I can definately reccomend this 
channel on Youtube - it contains loads of good instructions and 
step-by-step guides to proper work on and around PCB's and components:

http://www.youtube.com/user/SolderingGeek#p/u

In regards to the cleaning of a PCB, as also Don W3FPR was so correctly 
pointing out, DO NOT splash this all over your board like its' a bottle 
of after shave, but rather deposit in small areas with only trace 
amounts of alcohol at the time. You may find a cotton swab a suitable 
and more gentle alternative to a brush.

You can see in an example here (timestamp 3:58) how this can be performed.
http://www.youtube.com/user/SolderingGeek#p/u/37/G14rFgAfwXk

73 -
Brian OZ2BRN


Den 08-09-2010 20:22, Don Wilhelm skrev:
>    Stan,
>
> Do NOT attempt to remove the flux - it is not conductive and will cause
> no problems, even though it may look slightly "messy".
> In fact, attempts at removing flux can result in unanticipated
> problems.  If the flux residue plus solvent gets under connector headers
> or relays, or even ICs, it will not be completely removed and the
> residue left in those places can later make conductive paths where they
> should not be.  I did work on one K1 that had been completely ruined by
> an attempt at removing the flux.
>
> If you must clean a board, do it in small areas - do NOT flood the board
> with the solvent (yes, use de-natured alcohol, acetone can etch plastic
> components) - apply the solvent sparingly in a small area at a time, and
> blot it off with a paper towel.  Alcohol attracts water from the air
> rapidly, and the reduced temperature of the board caused by rapid
> evaporation will cause the water to condense on the board - wipe it up
> too, but do not apply power until it has completely dried.
> If you feel you must remove the flux, build up a small board (like the
> RF Probe from the parts provided in the K2 kit), and practice your flux
> removal technique on that first so you know what to expect.
>
> If you want to avoid a large flux residue, use a solder with a mildly
> reactive flux, such as Kester 285.  While Kester 44 is much better know,
> it has a highly reactive flux and leaves much more residue than the
> mildly reactive flux.  Save the highly reactive flux for soldering jobs
> that have noticeable oxidation on the surfaces.
>
> 73,
> Don W3FPR
>
> On 9/8/2010 1:43 PM, stan levandowski wrote:
>> I've been told that it is good practice to clean a completed PC board
>> with either acetone or denatured alcohol and a small toothbrush.
>>
>> I could not bring myself to do this when I completed my KX1 - it just
>> seemed (at least to me) somewhat risky to be brushing a liquid with a
>> nylon toothbrush all over a populated board.
>>
>> Now I'm faced with the same issue as I begin my K2.  I want to do
>> "everything right" because this K2 is going to be my  "baby" -- but.....
>>
>> So I am asking for some opinions on just what the risk/benefits are and
>> perhaps to get some idea as to whether this is really a practical and
>> useful process or a "purist" finishing touch that returns marginal bang
>> for the buck.
>>
>>
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