4 thoughts:
1) MEK is not too people friendly, check out the MSDS compared to alternatives

2) MEK is an effective degreaser, but this does not make it an effective flux
remover. There are other things in flux residues which the MEK will not address.
These are basically any non grease like substances such as ionics etc  and perversely
these are the items of concern. Quite likely if you ran some SIR checks you will find
that your numbers are worse after cleaning than before.

3) The obvious question : why are you removing RMA flux which is[was] defined as a no
need to clean product?

4) "SOME of our assembly techs..." ???? What do the others do? Just curious.

I think it might be better to ask: What is the objective, what is the best way of
acheiving it, how will I know?

If you are cleaning for cosmetic reasons it could be that you end up just dumping the
whole process.

Mike Fenner
BSP, OX15 4JQ, England
T: +44 1295 722 992
M: +44 789 999 7715
F: +44 1295 720 937


-----Original Message-----
From: David Hipp <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: 02 September 1999 16:29
Subject: [TN] Flux Removal with MEK


>TechNetters - some of our assembly techs use MEK to remove flux. I know MEK
>is potent and probably shouldn't be used for flux removal. What I need is
>some justification WHY we shouldn't use MEK.
>
>We are soldering 22 gauge stranded wire to connector lugs and microswitch
>turret terminals. This assembly is part of a fuel control for commercial
>fanjet engines. We use Sb5WS (Tin 94%, Lead 0.2%, Antimony 4-6%) solder and
>Kester 197 Flux, which is type RMA.
>
>Any help is appreciated.
>
>Regards,
>Dave Hipp
>Woodward Aircraft Engine Systems
>Electrical Production Engineering
>(815) 639-6732
>FAX (815) 636-6040
>
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