Tom,
I think you are missing something. In both scenarios you describe, you
have USED two different types of fluxes on one assembly but have not MIXED
two different kinds of fluxes on one assembly. When you wash the water
soluble flux, it is gone (well, in theory at least), and so you are not
mixing fluxes.
I would also caution those who might think that when you mix a no-clean and
a water soluble flux that a cleaning operation removes the water soluble
flux. Not the case. When you mix chemistries, you have an amalgam which
is often very resistant to cleaning, and still corrosive.
Doug Pauls
"Tom Parkinson -
Quality System To: [log in to unmask]
Manager - cc:
WinTronics, Inc." Subject: Re: [TN] Mixing fluxes - more
<tomp@WINTRONICSI
NC.COM>
Sent by: TechNet
<[log in to unmask]>
03/11/2003 10:39
AM
Please respond to
"TechNet E-Mail
Forum."; Please
respond to "Tom
Parkinson -
Quality System
Manager -
WinTronics, Inc."
I've read the recent questions and information concerning mixing of
fluxes. I agree - do not mix flux types when soldering. However,
here's one for you that can be looked at from a couple of angles....
1. I build a board - wave solder using washable flux. Flux is
activated, does it's thing, and board is soldered.
2. Water Wash and Dry the board. All washable flux residue is gone.
3. Add a couple of more components that CANNOT be washed (water will
enter the component and ruin it), using NO-CLEAN.
4. Board is done.
Technically, I have used 2 types of fluxes on one assembly....
Another scenario:
1. Board (described above) is finished. But, fails test - I find a bad
component...
2. I have to use NO CLEAN to replace the component because I cannot
water wash the board (remember the other components that cannot be
subjected to water wash..)
3. Board is done. Passes test - finished.
Again - Technically, I have mixed fluxes on the same assembly.
In the above description, I do not see a problem - or am I missing
something?
Thanks,
Tom
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