Actually, it is much worse than "looks bad". Benchtop applications of liquid no-clean flux are typically done with a needle bottle, when they should be applied with a felt-tip applicator only to the solder joint to be reworked, or not applied at all but use the no-clean flux in the core of the wire solder, which is usually sufficient if you get the 2.5% core.
The problem with rework using no-clean liquid is that too much is applied to be heated (and thus inerted) by the tip of the soldering iron. No-clean flux residues from solder paste are inerted when the entire CCA passes through the reflow oven, so that is a different scenario.
Some of the brands of active no-clean flux are just as bad as organic water soluble flux if left on the CCA. Lots and lots of good bedtime reading on the World Wide Web on this subject.
Really, when you think about it, liquid no-clean flux residues are one of the single biggest dangers to electronics reliability that are out there, outside of design issues. If allowed to be left on they are sticky, absorb moisture and dust/dirt, become conductive, promote organic and dendritic growth, etc, etc,. Read all about it at Foresite's website. http://www.residues.com
Remember, I am not talking about no-clean flux residues from reflowed paste.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
Sent: Friday, September 10, 2010 9:00 AM
To: [log in to unmask]
Subject: Re: [TN] Cleaning No Clean Flux
Also:
It looks "Bad".
The SMT paste no cleans don't look so bad but rework or THT that use no
cleans look a little messy.
Bob Kondner
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Rick Bell
Sent: Friday, September 10, 2010 9:57 AM
To: [log in to unmask]
Subject: Re: [TN] Cleaning No Clean Flux
----------------------
[quote]
"Also, why would "No cleans" need cleaning?"
----------------------
I'm willing to bet someone's chair that the most common answer is
"...because our customer requested it." That's true in our case, anyway.
We use a chemistry from Kyzen. IPA isn't capable for our process materials.
You'd probably have to verify for yourself if it works for you.
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert DeQuattro
Sent: Friday, September 10, 2010 8:41 AM
To: [log in to unmask]
Subject: [TN] Cleaning No Clean Flux
Hello Everyone. I know there has been a lot of interesting dialogue the
past few days reference hand solder and flux and cleaning. My question
is "is isopropyl alcohol acceptable to use to clean no clean flux"? We
have Novec flux remover, but that leaves a white residue similar to what
some of you have complained about during the course of the related
thread. Any ideas on the best way to remove or avoid this. Also, why
would "No cleans" need cleaning?
Thanks,
Bob DeQuattro
Quality Manager
VR Industries, Inc
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