Installation Guide

ManualsBrandsPlexiglas ManualsAcrylic Sheets48 in. x 48 in. x 1/4 in. Clear Acrylic Sheet

Stress may be introduced into a part during the thermoforming

operation, or during fabrication operations such as machining or

polishing. Stress may sometimes be held to a minimum by altering

the processing conditions when forming parts, and by using

sharp tools of the recommended types when cutting or machining.

For machining instructions, see page 11.

The possibility of crazing may be greatly reduced by minimizing

internal stresses by annealing the parts before cementing. For

annealing instructions, see page 30.

Low joint strength may be due to a number of causes. Improper

fit of parts, inadequate mixing of the cement, excessive clamping

pressures, or poor technique may all help weaken cemented joints.

The best way to avoid problems is to follow the recommendations

in this manual.

Preparation of the joint is very important when cementing

Plexiglas

MC acrylic sheet. The parts must fit accurately and

smoothly without force. If the parts do not match or fit well, the

edges to be cemented should be machined smooth to fit, but

should not be polished, since polishing tends to round edges.

Proper preparation of edges is necessary to ensure that little or no

internal stress is present in the material. Such stresses will cause

crazing on contact with solvent. To prevent crazing, avoid flame

polishing and dry belt or disc sanding where solvent contact may

occur.

Cementing Plexiglas

Acrylic Sheet to

Plexiglas

Acrylic Sheet

Cementing provides a versatile and simple method for joining

pieces of Plexiglas

acrylic sheet. Properly cemented assemblies of

Plexiglas

acrylic sheet have nearly the appearance of a single

piece; however, cemented areas of colored material, especially

white translucent colors, may deviate from the original color

when the joints are viewed under certain reflected- or transmitted-

light conditions.

Cementing permits the manufacture of parts that cannot

conveniently be made by other methods because of process

limitations (e.g. part size, undercuts), low production volume, or

cost. Good cemented joints are also air- and water-tight.

The two types of cement used for Plexiglas

acrylic sheet are

solvent cements and polymerizable cements. The solvent

cements may be used as supplied, or may be thickened with

Plexiglas

acrylic sheet chips or Plexiglas

acrylic molding resin.

Polymerizable cements, such as PS-30

™

and Weld-On 40

™

or 42

™

are viscous as supplied.

Solvent cements work by softening and swelling the Plexiglas

acrylic sheet, permitting actual cohesion of the parts. After assembly,

the solvents evaporate or dissipate through the material, leaving

a hard, clear joint. Thickened solvent cements work the same

way, but allow for longer solvent action due to slower evaporation,

limit capillary flow between two closely fitted surfaces, and provide

limited gap-filling capability. The polymerizable cements have little

or no solvent action, but actually form new polymer in the joint,

thus holding the parts together.

Both Plexiglas

G and MC acrylic sheets may be cemented with

either solvent or polymerizable cements. Generally, however,

a polymerizable cement, such as PS-30 or Weld-On 40 or 42,

provides better joint strength and appearance.

Any of the unthickened cements may be used if the parts will

not be used outdoors. The choice may be governed by the

availability of the solvent or by previous experience with a particular

cement. (Cement PS-30 or Weld-On 40 or 42 is best for outdoor

use, however.)

For names of manufacturers of cements discussed in this manual,

call the Altuglas International Polymer Technology Center at

800-217-3258 your local Plexiglas

acrylic sheet distributor, or

one of the Sales Offices listed at the back of this manual.