Amol,
We don't use conformal coatings, so I can't give you a good answer.
I will say that while our friends at 3M are trying to find the perfect
solvent:
good solvency
non-material damaging
non-flammable
non-carcinogenic
non-teratogenic
non-mutagenic
non-ozone depleting
non-global warming
and these Novecs are way better than the CFCs and PFCs and even most
HCFCs for the latter
Novec solvents (for example,
1,1,1,2,2,3,3,4,4-nonafluoro-4-methoxybutane) have global warming
potentials ranging from 40 to 320, depending on which one and the method
used to calculate the GWP. It also matters whether you are going to use
them neat or in some of the mixtures that 3M sells.
As solvents I think they are worth looking at, but personally I would
think they are better suited for batch or conveyorized cleaning where
you have vapor and liquid capture systems in place. But then you also
have to balance GWP concerns (if you have any) against all the other
concerns that I mentioned above. There is no perfect solution.
Bev
RIM
Opinions expressed here do not necessarily represent those my employer,
Research In Motion.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Kane, Amol (349)
Sent: Monday, June 29, 2009 8:16 AM
To: [log in to unmask]
Subject: Re: [TN] Alcohol Distillation
Thank you for the very enlightening responses from Technet (as always).
I am also investigating alternate solvents to use for (hand) scrubbing
boards prior to coat (to remove light oils, finger prints and flux
residues (if any) from hand soldering operations etc.)
Currently looking at the 3M Novec line of cleaning fluids. What are
y'all using out there?
Thanks,
Amol
-----Original Message-----
From: Brian Ellis [mailto:[log in to unmask]]
Sent: Saturday, June 27, 2009 2:10 AM
To: TechNet E-Mail Forum; Kane, Amol (349)
Subject: Re: [TN] Alcohol Distillation
The thing that shocks me is not the desire to distill IPA but the fact
that you USE IPA before conformal coating. It is not a good defluxer.
Distillation is not easy. The Black Foresters gather cherries and put
them in large tubs for a few weeks and then distill the fermented juice.
They never get pure alcohol, but a deliciously perfumed eau-de-vie
called Kirschwasser with a distinct aroma of the cherries it was derived
from. Why? Because of azeotropes. Even a mixture of ethanol and water
will not distill into pure alcohol but into a mixture of about 96% EtOH.
Rudy mentions esters; these are the reaction products between alcohols
and acids and it is what gives Kirschwasser its aroma and flavour.
Esters usually form azeotropes with alcohols and it is not impossible
for raw organic acids to do so as well. So distillation may remove most
of the rosin but the resultant juice may not be brilliant as a safe
defluxer, possibly even worse than not cleaning at all.
Apart from which, alcohol vapours and air can form a highly explosive
mixture. H&S regulations would require you to install such a still in an
explosion-proof bunker KABOOOOM!
Brian
Kane, Amol (349) wrote:
> I am looking for some information from people who own a alcohol
distillation unit that converts alcohol waste (alcohol + fluxes etc.,)
into usable alcohol again. I know that such a unit exists, but need to
talk to people who actually use it. We are trying to limit the amount of
IPA waste we generate from clean boards prior to CC.
>
> Offline replies are welcome too.
>
> Thanks and regards,
> Amol
>
>
>
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