Cleaning fingerprints, nose smudges, and other superficial marks
from the cold-side cover plate is generally not more difficult than
from a normal plate glass window. However, because the surface hardness of
the cover glass may be considerably less than that of normal plate glass, harsh
fluids and abrasive napkins should not be used.
Cold-side cover plates (2.53-2.7 g/cm3 density) may be
cleaned with a water based neutral liquid detergent in distilled
water, with reagent grade ethyl alcohol (200 proof C2H5OH),
or with a 20% NH4OH/80% C2H5OH
solution followed by an ethyl alcohol rinse. Fluids are easily
applied using a squirt bottle, and wiped off with soft, lint-free
paper napkins or cotton material approved for shielding-window cleaning.
Hot-side cover plates and alpha shields (2.53-2.7 g/cm3
density) may be cleaned with the same materials as cold-side cover
plates. However, any material from in-cell operations deposited on
the glass surface must be removed prior to fluid application to
prevent possible chemical reactions
Glass surfaces of the interior window slabs (3.23-5.20 g/cm3
density) must be cleaned very carefully, as the plates have a high
lead content and are relatively soft. Also, an "orange peel"
condition may develop if a window which has been etched to reduce
reflection is cleaned improperly. Water, or water-based cleaners, are
not recommended for use on these slabs, as water can leach the glass
and ruin the surface if not removed quickly.
After a glass slab has been cleaned, it is visually inspected using a
100,000 to 200,000 candlepower lamp held at an oblique angle to the
glass to reveal reflections caused by smears. Smears may not be visible
if the lamp is not held at an oblique angle to the window surface.
Window cleaning experience has determined that short, linear
wiping strokes clean better than circular motions; circular
motions tend to further spread the smear, rather than remove it.
After each linear swipe, the napkin is turned to a clean surface to
avoid redepositing materials that had been removed.
A Static-Master (trade name) brush is used during final cleaning
to remove dust and lint particles from the window. During the
cleaning operation, a small static charge is built up on the glass
surface, and this charge attracts dust particles and lint. Dust
particles in the air may be locally controlled during the cleaning
operation by the operation of a positive ion generator in the close
proximity to the window.
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Data and information contained in the tutorial was written by Dale A. Tobias, Premier Technology, Inc. and Hienz E. Hoffman and William G. Wash, Schott Glass Technologies, Inc. and may be reproduced only with written consent.
For information, contact Lyle Freeman
Vice President of Business Development
(208) 782-9129 lfreeman@ptius.net
