[Elecraft] K2 Cleaning PCB

[Ron D'Eau Claire]

Hi Rick!

You might want to check what the K2 manual says on this subject in the
section on soldering (page 11 in the latest version).=20

This is the "official" word from Wayne:

"(DO NOT use acidcore solder, water-soluble flux solder, additional =
flux, or
solvents of any kind, which will void your warranty)"

Flux remover of any kind, including alcohol, is a "solvent".=20

When circuit boards came into use, a decision was made by NASA to clean =
the
boards. I've heard endless reasons for this being done. The one that =
made
the most sense, at least back in the 60's, was to reduce the amount of
debris that could "migrate" (float around) and get into other things. In
extreme cold rosin gets very hard and brittle. Under vibration, or =
thermal
stress, flakes can come off.=20

The decision to clean boards required using only electronic components =
that
would not be harmed by the solvent. I don't know whether all the =
components
Elecraft uses meet these criteria.=20

In any case, the debate about whether or not there is any value at all =
in
cleaning a board has raged on for decades, and will likely do so for a =
long
time to come. When I worked in the field servicing equipment, I =
carefully
checked the manufacturer's instructions because a LOT of them have a
statement like the one above in the Elecraft manual.=20

Even manufacturers building gear to be used in the relatively corrosive
(salt air), humid atmosphere on a ship often voided their warranty if =
there
was any evidence of flux having been removed.  I suspect it was because =
many
people in the field sprayed the boards with all sorts of strong stuff in =
an
effort the clean them off quickly - stuff that could do a lot of =
collateral
damage. I never had a chance to ask a manufacturer if that was so. Since =
I
expected the manufacturer to stand behind their equipment if I had =
problems
fixing it, I followed their instructions for working on it.=20

Ron AC7AC
K2 # 1289

-----Original Message-----
Hi all,

I'm about to start in on my RF board.  There are a lot
of references to flux removal but I don't know what
the prevailing opinion is on the subject. Perhaps a
poll on how many attempted flux removal during the
building process? At NASA soldering class we were
taught to clean everything with pure alcohol (and only
pure alcohol) and a stiff acid brush. Sometimes the
final board would be immersed in an alcohol
bath/ultrasonic cleaner for final cleaning. I don't
think a K2 has been launched to deep space yet so the
standards don't have to be so rigorous! If nothing
else a flux-free PCB sure looks better IMO! So should
I bother or do the risks out way the rewards in this
case.

Thanks=20
Rick N3IKQ  K2 #3465=20