I am pleased to see the matter of the unsuitability of IPA as a post solder
flux remover raised here, I am not even sure it is better than nothing. Good
luck on trying to change it though, as you say you have to overcome
established practice not just in your place but the industry. 
I think we are all the victims of slightly woolly thinking, such as: "IPA is
used to make the flux  so it must be able to dissolve it off afterwards
right?"
The first part of the statement is true the second part is wrong; After the
flux has been cooked to >200C, and has been chemically reacted with some
metals it's not the stuff that was in the bottle. And that's what Brian is
saying below, but more cleverly.


Regards 

Mike 


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Hernefjord Ingemar
Sent: Wednesday, August 29, 2007 11:27 AM
To: [log in to unmask]
Subject: Re: [TN] The perils of using Alcohol for cleaning

Hi,
is 2-propanol and isopropanol exactly same? We changed from 2-propanol
to isopropanol some years ago (not same articl number). Thought myself
for years, that these two were not equals.

E.g. http://www.canal-h.net/webs/sgonzalez002/Quimica/ALCOHOLS.htm

/Inge 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis
Sent: den 29 augusti 2007 10:54
To: [log in to unmask]
Subject: Re: [TN] The perils of using Alcohol for cleaning


Phil Quixote

Yes, right windmill. I'm sure that there is discussion of this in the
earlier Solvents Assessment Reports (in the 1990s) of the Technical and
Economic Assessment Panel of the Ozone Secreatriat. I tried to find it
at
http://www.unep.ch/ozone/Assessment_Panels/TEAP/Reports/TEAP_Reports/ind
ex.shtml
but come up with couldn't be found. Try asking them for a hard copy of
the 1998 TEAP Assessment Report: it may mention it. Searching through my
archives I find the following on p 2-18 of the 1998 UNEP STOC Assessment
Report:
"Amongst the flammable solvents, the one that is most frequently quoted
for electronics defluxing is isopropanol. Unfortunately, this solvent,
although it will dissolve rosin residues reasonably easily, has very
limited solubility for most of the other by-products resulting from the
soldering process unless it is extremely pure. Continual purification
can be achieved by high-volume distillation in an approptriate machine,
but this is very energy-intensive and expensive. It is not recommended
to use this product by itself..."

Does this help?

Brian

Phil Nutting wrote:
> Good morning,
> 
> Over the recent years there have been discussions about the ionic 
> residue left behind by alcohol when used as a cleaning agent.  You 
> have me convinced.  Now I have to convince my organization.  Is there 
> some document, standard or other item which I can use as a reference.

> Simply stating that "the experts on TechNet said so" won't carry
enough weight.
> Not would using alcohol for cleaning would be a change and we all know

> change = death.  Just because something has been done one way for 20+ 
> years does not make it right.  Hopefully I chose the right windmill to

> tilt at.
> 
> Phil
> 


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