CHrome alum solution usually has lower pH than optimal for hardening.
But when pH is raised to optimal range, chromium may form insoluble
hydroxides and precipitate out. Also, sufficient amount of chromium may
leave some color in gelatin layer. These are some of the difficulties of
using chrome alum as a hardener.
If slow rate of crosslinking is ok, bisepoxide hardener I have been
using in addition to glut is very good. No fume, and when used with
usual care, it is pretty safe.
Received on Mon Oct 3 13:42:52 2005
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