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January 2005

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Subject:
From:
"Ingemar Hernefjord (KC/EMW)" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Ingemar Hernefjord (KC/EMW)
Date:
Mon, 31 Jan 2005 08:25:26 +0100
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50 years!! So you were a child worker..
/Ingemar

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]
Sent: den 28 januari 2005 13:14
To: [log in to unmask]
Subject: Re: [TN] Flux for solderability testing


IMHO, only 25% water-white rosin should be used for solderability 
testing, on the principle that a) if it solders with that, it will 
solder with anything; b) it is the only standard by which discussions 
can take place between, e.g., supplier and user; c) the vapours of all 
fluxes are, to some degree or another, toxic (a lot of them being worse 
than colophony).

The toxic effects of colophony have been greatly exaggerated. It is true 
that hand soldering at 350°C may produce minute quantities of aldehydes 
and this argument was used to try and scare people into using a 
synthetic flux about 20 or so years ago. I have about 50 years 
experience of soldering with rosin-based fluxes and I've NEVER come 
across a single case of asthma sensitisation. I have come across 2 cases 
of skin problems with DIN 8511 F-SW32 fluxes but this was due to the 
acid activator and not the rosin. Changing to F-SW26 (also rosin-based) 
solved the problem (and, incidentally, made soldering easier).

Solderability testing uses only minute quantities of rosin and is not 
done every minute of the day with the operator's nose stuck where he can 
breathe in the fumes. The risk is negligible. If you are worried, you 
can even extract the fumes. And do remember that 99% of electronics hand 
soldering, producing greater quantities of fumes, up to the advent  of 
"no-clean" soldering, was done with rosin (and probably 50% still is). 
My advice is therefore use colophony and don't seek monsters that don't 
exist.

Brian

Alistair Murray wrote:
> For health & safety requirements, I am seeking an alternative test flux
> to that prescribed for use in the solder testing of PCBs.
> 
> This test flux comprises 25% colophony in alcohol. 
> 
> Colophony is classed as a Sensitizing Agent for Occupational Asthma. 
> 
> LEV is an option but I would prefer to use a safe flux of similar
> "activity".
> 
>  
> 
> Does anyone know of a colophony-free flux of similar activity? I regret
> that I do not know the activity of the colophony flux (acid value?). Is
> there a way of comparing it with the activity of a synthetic flux?
> 
>  
> 
> Many thanks in anticipation
> 
>  
> 
>  
> 
> Alistair Murray
> 
> Artetch Circuits Ltd
> 
> UK
> 
>  
> 
> 
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