Full Product Manual

34
The masking paper used on Plexiglas
®
acrylic sheet is not water
repellent. If masked Plexiglas
®
acrylic sheet is soaked with water,
a white residue may be left on the material when the masking paper
is removed. To avoid this, store masked sheet where it cannot come
into contact with water. If a residue is deposited on the Plexiglas
®
acrylic sheet, it may be removed by wiping the surface gently with
a clean, soft, damp cloth and drying it with a soft flannel cloth.
Unmasking
Plexiglas
®
acrylic sheet can be unmasked by lifting the masking
paper along one edge and rolling it around a dowel or cardboard
tube. The paper may be built up on the dowel or tube in successive
layers using the adhesive layer to secure the turned up edge of
the masking to the paper-covered dowel. Remove all residual
adhesive from the sheet surface at the time of masking removal.
Any residue that remains can be cleaned off by wiping with a
soft clean cloth dampened with isopropyl alcohol.
Unmasking usually builds an electrostatic charge on the
Plexiglas
®
acrylic sheet. The electrostatic charge attracts dust
and lint to the acrylic surface. Eliminate the charge by wiping the
sheet with a dampened cloth after unmasking. During dry weather,
wet down the shop floor occasionally to minimize dust.
For operations such as a strip heating, cementing, or applying
glazing sealants, only the masking paper in the area being worked
on should be removed from the sheet. When cutting out small
sections of masking paper, take care not to score or scratch the
Plexiglas
®
acrylic sheet surface underneath. Scoring the sheet may
reduce its impact resistance.
Special tools can be employed to minimize the possibility of
scoring or scratching the Plexiglas
®
acrylic sheet when removing
small masking sections (contact Altuglas International for information
on commercial tools and materials for Plexiglas
®
acrylic sheet).
When used properly in combination with a suitable solvent,
these tools will not score or scratch the sheet.
Masking paper may be difficult to remove in the following
circumstances: 1) Plexiglas
®
acrylic sheet that has been stored
outdoors and exposed to sun and moisture; and 2) sheet has been
stored indoors for lengthy periods or has been exposed to heat or
high humidity. When the sheet will be thermoformed, and the masking
paper is not adhering too tightly, flash heating the sheet for 60
seconds at 350°F will loosen the paper enough for easy stripping.
In cases where the paper is sticking more tenaciously, it may
be necessary to choose a more aggressive solvent to loosen the
masking paper. In such cases, thoroughly soak the masking paper
with the solvent, and allow at least 10 minutes for the solvent to
penetrate the paper. Strip as described above. If necessary,
apply more solvent along the separation line between the masking
paper and the Plexiglas
®
acrylic sheet.
Use only solvents that will not attack the Plexiglas
®
acrylic sheet.
A list of recommended solvents for removing masking paper is
available from Altuglas International. Remove the solvent from
the Plexiglas
®
acrylic sheet as soon as possible by first washing
the sheet with isopropyl alcohol, then with soap and water and,
finally, with clear water.
Before attempting to remove tightly adhering masking with
solvents, become familiar with the properties of the appropriate
solvents and take proper safety precautions. Obtain Material
Safety Data Sheets from the manufacturer. Ventilate the work
areas as OSHA requires, and prohibit smoking or open flame.
Unmasked pieces of Plexiglas
®
acrylic sheet should be stored
in the original shipping cases. Full cases can be stored on edge.
Open cases can be stored flat or they can be placed on edge in
roller-type racks. Uncased sheets may be stored in A-frame racks.
The interleaving tissues should not be removed until the sheets
are used.
Remasking
The masking paper used on Plexiglas
®
acrylic sheet will regain
its tack and may be replaced if desired. The adhesive bonds
firmly to itself, however, so the coated sides of the masking paper
must not be allowed to contact each other. The masking paper
can be rolled up in loose tubes and stored on pegs in a clean,
dry area. Take care to avoid
contaminating the masking paper with dirt to keep from scratching
the Plexiglas
®
acrylic sheet when the masking paper is reapplied.
Prepared masking papers are available from a number of sources
and may be used for remasking. Before using one of these products,
however, check its adhesive to be sure it will not attack the
Plexiglas
®
acrylic sheet.