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CLEANING
CHEMCAST® GP BEFORE PAINTING The surface of the Chemcast® GP acrylic sheet
to be painted must be clean. Surface contamination, even though
invisible, can cause paint failure. Solvents for dirt and grease
must be carefully chosen to avoid those which are harmful to
Chemcast® GP. Harmful solvents include chlorinated hydrocarbons,
acetone, toluene, xylene, lacquer thinners, and some paint
thinners. All of these craze Chemcast® GP. Even though crazing
may not be apparent immediately, Chemcast® GP surfaces which
have been treated with these solvents become sensitized to
crazing and may craze once in service. CLEANING VARIOUS TYPES OF
CONTAMINATION Masking Paper Adhesive Dab with the gummed surface of the masking
paper. If this fails, wipe with VM&P naphtha on a clean cloth
and rinse with a dilute water detergent solution. Or wipe with 99
percent isopropyl alcohol and rinse with clean water, most
preferably distilled or deionized water to prevent spotting. Water Soluble Contaminants Wash with a detergent water solution followed
by a fresh water rinse. Fingerprints Wipe with soft clean cloth dampened with 99%
isopropyl alcohol. Oil Soluble Contaminants Use a hydrocarbon solvent such as VM&P
naphtha, kerosene, or mineral spirits. Follow with a detergent
water wash and clean water rinse. Spray Masking Compounds Wipe the area with a damp synthetic sponge,
thenwipe the surface with VM&P naphtha or isopropyl alcohol. Grease Forming Compounds Wash with kerosene or mineral spirits. Follow
by washing with a detergent water solution and a clean water
rinse. Silicone Oils and Greases Avoid contact completely. Once contaminated
with silicones, Chemcast® GP is virtually impossible to clean. MASKING PAPER ADHESIVE When masking paper is removed from Chemcast® GP, particles of masking adhesive sometimes remain on the surface, and must be removed before painting. Dabbing the sheet with the gummed surface of the masking paper may remove the particles. If this fails, a solvent such as VM&P naphtha or 99 percent isopropyl alcohol can be used to clean the surface. Isopropyl alcohol may craze or whiten the surface of the Chemcast® GP on continued contact, and should be rinsed off promptly. The solvent should be applied with a soft clean cloth. The Chemcast® GP should be wiped gently, then the surface should be washed with a dilute solution of nonabrasive detergent in water. This should
be followed with a clean water rinse. If the masking paper has not left any residue
and the sheet has not been handled, it may be painted without any
special cleaning. SOLUBLE CONTAMINANTS Both water soluble and oil soluble contaminants
are present on Chemcast® GP which has been handled without
gloves after unmasking, or which has been exposed to the shop
atmosphere for any period of time. Water soluble contaminants can
be removed by washing with a detergentwater solution, and then
rinsing with fresh water. Oil soluble contaminants can be removed
from Chemcast® GP acrylic sheet only with hydrocarbon solvents.
Good quality VM&P naphtha, kerosene, or mineral spirits are
not harmful to Chemcast® GP and they evaporate rapidly without
leaving a residue. The surface of the Chemcast® GP should then
be washed with a detergentwater solution and rinsed with clean
water. FINGERPRINTS Fingerprints may be removed with a soft clean
cotton flannel cloth and 99% isopropyl alcohol. SPRAY MASKING COMPOUNDS Spray masking compounds may leave an invisible
film on clear areas after stripping. Unless removed, this will
affect the long term durability of the paint coating. The film
can be removed by wiping the area with a slightly damp synthetic
sponge. The surface of the Chemcast® GP should then be wiped
with VM&P naphtha or isopropyl alcohol before painting. GREASE Grease remaining on the Chemcast® GP after
forming on a grease covered form can be removed by washing with
kerosene or mineral spirits. This should be followed by washing
with a detergentwater solution and then rinsing with clean
water. The Chemcast® GP must be thoroughly dry when it is
painted as moisture will reduce the effective service life of the
coating. SILICONE CONTAMINANTS Silicone based oils and greases should not be
used anywhere in the fabrication area since it is virtually
impossible to remove these contaminants from Chemcast® GP. Paint
adhesion on Plexiglas contaminated with silicones is very poor. |
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Copyright © Plastiglas de Mexico 1999
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