Vical acrylic 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 masking paper to the paper­covered dowel. Al1 residual adhesive should be removed from the Vical acrylic at the time the masking paper is removed. Any residue that remains on the Vical acrylic surface can be cleaned off by wiping with a soft clean cloth dampened with isopropyl alcohol.

Unmasking usually builds an electrostatic charge on the Vical acrylic. The electrostatic charge attracts dust and lint to the Vical acrylic surface. The charge may be dispelled by wiping the sheet with a dampened cloth after unmasking. During dry weather the shop floor should be wet down occasionally to keep dust at a minimum.

For operations such as 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 Vical acrylic surface underneath. Scoring the Vical acrylic may reduce the impact resistance of the material. For best results, use a special, inexpensive device, the # 138 Unmasking Tool. It is available from most Vical acrylic Distributors or from Fletcher­Terry Co., Farmington, Conn. When carefully used in combination with a solvent such as Atlantic Safety Solvent or Ultrasene, the tool will not score or scratch the Vical acrylic.

Masking paper on Vical acrylic sheet that has been stored outdoors for long periods of time or that has been exposed to heat or high humidity may be difficult to remove. When the sheet will be thermoformed, and the masking paper is only moderately tight, flash heating the sheet for 60 seconds at 350°F will loosen the paper enough for easy stripping. In more stubborn cases, it may be necessary to choose a solvent from the list below to loosen the masking paper. Thoroughly soak the masking paper with the solvent, and allow several minutes for the solvent to penetrate the paper. Strip as described above. If necessary, apply more solvent along the line where the masking paper is separating from the Vical acrylic.

Use only solvents that will not attack the Vical acrylic. Recommended solvents for masking paper removal are:

· Ultrasene-a highly refined form of kerosene.

· Turpentine-steam distilled only.

· 90 parts Hexane/10 parts wetting agent.

Use harsher solvents only as a last resort. For the most difficult pallets, try a mixture of 50% toluene/25% methyl ethyl ketone/25% Cellosolve Acetate. 1­2% Cab­O­Sil may be added to prevent run off on vertical surfaces.

No matter which solvent is used, it should be removed from the Vical acrylic as soon as possible. The toluene/MEK/Cellosolve Acetate mixture should not remain on the Vical acrylic longer than 6 minutes at room temperature. Clean the solvents from the Vical acrylic by washing the sheet with isopropyl alcohol, then with soap and water, and finally, rinsing with clear water.

When using solvents, take all necessary safety precautions. These include providing adequate ventilation and prohibiting smoking or open flame in the working area.

Acrylic Sheet General Information