The Zinc Formalin I use from Anatech comes in 2 forms.  One is buffered
and the other is not and is slightly acidic.  Provided tissues are
fixed and processed within a short time, the non-buffered version is ok
for me.  But I can see how it may lead to formalin pigment and
corrosion (although I have never had such problems).  You may want to
switch to the buffered version which is known as Z-Fix from Anatech.

-Katie

--- "J. A. Kiernan" <jkiernan@julian.uwo.ca> wrote:
> On Sun, 20 Jun 1999 Gervaip@aol.com wrote:
> 
> > ... have been using zinc formalin for years now. It is wonderful
> for 
> > ... can rust metal lids on specimen jars and formalin pigments are
> > present in the sections.  
> 
>    This is a very interesting observation, because plain acidic
>    formaldehyde solutions take quite a while to generate "formalin
>    pigment" from haemoglobin. You say that you use the fixative
>    in a processor, so presumably you are fixing for a short time
>    such as overnight or 24 hours. Is this so? If it is so, then there
>    is an implication that formalin pigment generation occurs more
>    rapidly in zinc formalin than in simple acidic or non-neutralized
>    formalin. This is something everyone should know about. Please
>    tell us more!
> 
>  John A. Kiernan,
>  Department of Anatomy & Cell Biology,
>  The University of Western Ontario,
>  LONDON,  Canada  N6A 5C1
> 
> 
> 


===
Catherine "Katie" Bresee Bennett
Laboratory for Experimental Pathology
Department of Veterinary Pathology
Michigan State University

e-mail: bresee98@yahoo.com
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