[Elecraft] Cleaning solder flux

[AL7CR]

Moderator save us … PLEASE

On Sun, Jan 2, 2022, at 7:12 AM, Dr. William J. Schmidt wrote:
> During my under-graduate and graduate school careers, I worked at
> Honeywell's circuit board fabrication shop for about a year and a half.  We
> had two machines in the shop that dealt with flux: a reflow machine and a
> parts set machine.  The reflow machine was used to reflow the solder after
> plating so that it looked shiny.  The board was emersed in a 601-type flux,
> heated to about 425F, cooled down, and then scrubbed (brushed) with
> Isopropanol alcohol three times (stages) with a water rinse and force-air
> dried (all automagically).  The solder was beautiful and shiny at the end of
> this process.  The parts-setting machine was similar... the whole
> (pre-reflowed) board was fluxed, the parts set, heated, and then cleaned.
> All fluxes come off with Isopropanol alcohol (remember IPA is polar like
> water and works that way).
>
> 
>
> Fluxes come in various forms... some are more corrosive and some not... so
> you should follow the directions (right off the website).  Rosin can remain
> on a board, but also can be problematic because it can collect debris (dust
> and other unwanted materials) because its plastic (flows at room
> temperature) sticky.  Many of the water-soluble fluxes are more acidic, and
> will tarnish the solder joints if not removed.
>
> 
>
> On the subject of using water on electrical components... most components
> (particularly if they might be mil spec) are made for water emersion (NOT
> ALL!).  In my office lab we routinely clean circuit boards by scrubbing them
> with just water and force-drying them.  Works fine.  About a decade ago, I
> used to buy up surplus AM/ broadcast band transmitters for repurposing to
> other countries (mainly south America) for the Christian broadcasting
> markets.  Once back at my shop, the first stop was a good through power
> washing in the driveway (paper and other water damaged goods removed of
> course) followed by a good drying (leaf blower).  Works fine!
>
> 
>
> 
>
> Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
> VP2EHZ
>
> 
>
>
>
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