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Date: | Fri, 28 Jan 2005 14:14:11 +0200 |
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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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Technet Mail List provided as a service by IPC using LISTSERV 1.8e
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Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
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