Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cwjcc!gatech!ncar!noao!asuvax!mcdphx!mcdchg!ddsw1!corpane!sparks
From: sparks@corpane.UUCP (John Sparks)
Newsgroups: sci.electronics
Subject: Re: nasty fluorocarbons
Summary: water based resins and such
Message-ID: <362@corpane.UUCP>
Date: 20 Feb 89 19:45:56 GMT
References: <24497@amdcad.AMD.COM> <1989Feb18.234109.3779@utzoo.uucp>
Organization: Corpane Industries, Inc., Louisville Ky
Lines: 56

In article <1989Feb18.234109.3779@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes:
> In article <24497@amdcad.AMD.COM> phil@diablo.amd.com () writes:
> >We buy these spray cans of TCE for defluxing circuit boards. I
> >know that fluorocarbons are bad for the ozone layer and in this
> >case, we're not just talking about the propellant, but the contents
> >delivered by the propellant are fluorocarbons (I believe).
> >
> >What alternative do we have? ...
> 
> My impression is that at the moment, the answer is "none".  In many
> applications of halocarbons (fluorocarbons etc.), they have been chosen
> for the job more for convenience than because there aren't any viable
> alternatives.  Electronics cleaning is one of the exceptions, though,
> where good substitutes are very difficult to find.
> 
> There is work in progress on finding variants that will do the job but
> won't be as harmful (the potential for ozone-layer damage varies enormously
> among even fairly similar compounds), but it hasn't reached the stage of
> marketable products yet.
> -- 
> The Earth is our mother;       |     Henry Spencer at U of Toronto Zoology


For your application (small number of boards, hand soldered and cleaned)
your are correct. I know of no alternative to using the spray flourocarbon.

But for large batches of circuit board cleaning there is much reaserch going
on to reduce flourocarbon output into the atmosphere.

Here at Corpane, our major business is vapor degreasers, circuit board 
cleaning machines, and vapor phase soldering machines. One of our companies
unique features is the method we use to pratically eliminate any flourocarbons
from escaping (not 100% , but at least 1/4 of any of our competitors)

We use a variable heat refrigeration system to heat the solvents, which
creates a vapor blanket over the liquid solvent. The cold side of the
refrigeration system condenses the vapor back into a liquid to be reused.

The physical layout of our system keeps most of the vapor from escaping
into the atmosphere. 

We are also looking into alternative technologies, such as water based
resins on surface mount (vapor phase) boards. This would allow the resin
to be removed from the boards with a water based cleaner. However, this
raises it's own problems, such as water pollution from the resin.

It's a tricky area. 

disclaimer: This is MY opionion. not corpanes.


-- 
John Sparks      // Amiga  |  {rutgers|uunet}!ukma!corpane!sparks 
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