[alt-photo] Re: fumed silica

[Richard Sullivan]

What I use is the most commonly available version, at least in the US. What
you describes sounds like it!

--Dick

-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org
[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
Loris Medici
Sent: Friday, December 16, 2011 3:57 PM
To: The alternative photographic processes mailing list
Subject: [alt-photo] Re: fumed silica

That's good news, then I'm going to get some tomorrow morning! (I can
buy a product named AEROSIL 200 locally - which is close enough to the
specification you gave below; 200m2/g surface area, and it's
hydrophilic too.) It looks like a very interesting thing to try; it
may prove a very useful primer additive for printing gum / casein on
non-porous / slick surfaces too! (That's my main concern for the
moment...)

I did some additional searching too:
http://www.springerlink.com/content/2qwuhntutubkc1kf/fulltext.html.
What's critical (in terms of hazard) is the "crystalline" silica
content of the stuff. Silica fume / fumed silica is "amorphous"
silica, not crystalline - but, apparently, some silica fume (amorphous
silica) products "may" contain (trace amounts of) crystalline form...

Regards,
Loris.


2011/12/17 Richard Sullivan <richsul at earthlink.net>:
> ...
>
> First off it does not cause silicosis. Apparently it is too fine for that.
>
> Wiki:
> "Health issues
>
> Fumed silica is not listed as a carcinogen by OSHA, IARC, or NTP. Due to
its fineness and thinness, fumed silica can easily become airborne, making
it an inhalation risk, capable of causing irritation."
>
> http://www.tomps.com/pdf_vault/MSDS/CABOSIL_MSDS.pdf
>
> It is not silica flour, it is fumed silica another animal altogether.
>
> It can, according to the MSDS it can be irritating but is not carcinogenic
or very dangerous in normal handling situations. It's widely used in
industry from dairy desserts, cough syrup (as a thickener) to
> face powder (to keep it flowing) and it makes microporous inkjet paper
microporous.
>
> It is in the size range of cigarette smoke. 150 sq M of surface area per
gm.
>
> ...
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