Date: Wed, 8 Nov 1995 10:04:33 -0500
From: JHocut@aol.com
Subject: H100 Foam Problem ?

The H100 foam for my landing gear bulkheads has been
sitting in my workshop for about two weeks.  It has 
become discolored over about 1/3 of it's surface, turning
a color somewhere between dark blue and purple 
instead of the original tan.  It has not been exposed
to sunlight, and the only "chemical" fumes it may have
been exposed to are whatever has been coming from
the 2427 epoxy during layups.

This is very strange indeed, and has me just a little
concerned since a color change in a material is usually
indicative of a chemical change or decomposition.  Has 
anyone else seen anything like this?  Is this foam still
OK to use?


Thanks,


Jim Hocut               jhocut@aol.com

From: Marc J. Zeitlin <marcz@hpwarhw.an.hp.com>
Subject: H100 Foam Problem ? (fwd)
Date: Wed, 8 Nov 95 10:21:24 EST

Jim Hocut writes:

>The H100 foam ......... has become discolored over about 1/3
>of it's surface, turning a color somewhere between dark blue and purple
>instead of the original tan.........

>.....a color change in a material is usually indicative of a chemical
change or decomposition.  Has  anyone else seen anything like this?  Is
>this foam still OK to use?

I have pieces of this foam sitting around the basement (clearly not
exposed to any UV except what comes out of the flourescent lights) and
have notices slight discolorations as well, although not as pronounced
as Jim H. indicates.  I have not noticed any property (stiffness,
density, surface roughness, frangibility, etc.) differences in the
discolored foam, and have used it in layups without any problem.

I GUESS that there's some surface change going on due to light exposure
and/or oxygen exposure, but that it's superficial.

--
Marc J. Zeitlin                               Email: marcz@an.hp.com