Re: Alum

s carl king (sanking@hubcap.clemson.edu)
Mon, 25 Mar 1996 20:48:51 -0500 (EST)

>
> Peter,Klaus, Sandy
>
> 1 There is never any necessity to use formaldehyde.
>
> 2 There are plenty of safer ways to achieve the same effect i e hardening.
>
> 3 As the strength of the chrome alum solution needed to harden gelatine enough
> but not too much, is probably less than one tenth of a gram to a litre, the
> risks are hardly high.
>
>
Terry, Peter, Klaus, Judy et al,

My original posting on the use of formaldehyde versus chrome alum was
simply to alert Carole that the later was in fact a very toxic chemical.
I conclude from my readings from various sources that both formaldehyde
and chrome alum are toxic and proven carcinogens, and
in the oridinary ways in which we use them are equally dangerous (or safe).
With specific reference to Terry's comments above:

1) Perhaps there is no necessity to use formaldehyde, but
it is very effective in hardening gelatin, and has a long history of use. In
my case I use it almost exclusively in carbro sensitizers, which are
very sensitive to change. I could substitute, but that in exchange for
considerable experimentation to get back to ground zero.

2) What are they? Glyoxal? Others? Is there a history of long
term use? What scientific data is this based on? And what about the
science that assured us that Mad Cow Disease posed no risk to humans?

3) Yes, diluted as in practical use I am sure that chrome
alum poses no great risk, and for that reason I continue to use it, as
I do Pyrogallic acid, which is also a dangerous chemical. But there is
also a risk in mixing the *dry* chemcals into solution. How much of
a known carcinogen can one inhale safely? 1/10000 of a gram, 1/1000
of a gram, 1/100 of a gram?

Sandy
Sanking@hubcap.clemson.edu