Presensitized
Printing plate 6 By Mr. Bob Gumbinner
I
took some of the grained and also chemically etched uncoated sheets
to both an outfit in Mount Vernon that was anodizing aluminum and an
Alcoa plant in Kensington, PA and had them anodized.
We
then immersed them in a zirconium fluoride solution and applied the
diazo. When imaged and put on a printing press this anodizing
treatment the length of run was substantially increased. I therefore
worked with Century Engineering to design a line to be able to
continuously anodize a web of aluminum. For the anodizing section
we contracted with a company that made rectifiers to build two rubber
lined tanks with ten foot diameter rubber covered drums. The
cathodes were lead pipes that lined the inside of the drums through
which cooling water was pumped. The electricity was introduced into
the aluminum web by an 18 inch diameter copper roller. First, we
used a commutator to connect the roller to the poser supply, later we
used carbon brushes. Century Engineering proved the unwind stand; a
six brush slurry graining section with rinse and the tanks after the
anodizing section to apply the interlayer and rinse and dry. We used
the same squeeze roll coating method that we used on the tank line to
apply the diazo. This caused the web to wander so we installed an
electric eye to adjust the pressure on the squeeze rollers to keep
the web in alignment. After a year of operation, the ceramic seal on
the shaft of the drums leaked. This was because when the tanks were
empty the entire weight of the drum was on the seals. When the 15%
sulfuric acid solution was added this lifted the drums up. We then
ran this, the B-line, with the sulfuric acid solution only in the
lower half of the tank. We obtained sufficient anodizing operating
this way.