Cementing

Equipment and Materials

ACRYLITE® acrylic sheet can be easily joined to itself or other acrylic surfaces with many commercially-available solvent cements such as ACRIFIX®. These cements are available from Authorized ACRYLITE® Sheet Distributors.

All cements should be used only in well ventilated areas with the proper protective equipment as recommended by the manufacturer. Also, before using any solvent or cement, obtain and review the Material Safety Data Sheet (MSDS), available from the manufacturer, for that particular product.

If the joints to be cemented are hard to reach or the parts don't, fit together precisely, you may prefer to use viscous cement. See the complete line of ACRIFIX® solvent cements.

Other items needed are likely to include a solvent cement applicator (needle-nosed plastic container shown below; see equipment suppliers listed at the bottom for details), pins or wire brads, and a dip or soak pan. You may also need forms, clamps, and weights of the proper sizes and shapes for the pieces to be cemented.

Preparation

The first step is preparing the area to be cemented. Edges must be cleanly cut and/or properly machined. If a dull blade was used for a saw cut, resulting in a melted or chipped edge, contact between the sawed edge and solvent may result in crazing of the material. Finish all rough edges on a jointer, shaper or edge finisher. If you cannot do so, wet-sand the edges with a flat surface or block.

Do not polish edges which are to be cemented.

Polishing will produce a convex edge with rounded corners and will result in an unsightly, weak joint. Also, a flame-polished edge may craze when it contacts solvent cement.

Crazing may also occur if internal stresses from shop fabrication are high. To eliminate such stresses, anneal the piece at 180°F (8O°C). When annealing, the heating time and the cooling time in hours should each equal the material thickness in millimeters, up to 6 mm. For example, you would heat a 3 mm-thick sheet (0.118") for three hours and allow it to cool gradually for three hours.

For thin sheet, the annealing (heating) time should not be less than two hours. It is not necessary to heat any piece for more than six hours, though it will not be harmful if heating time is extended due to shift schedules, etc. Remember, each hour of heating time requires a corresponding hour of cooling time.

Capillary Cementing

Capillary cementing is probably the most popular way of joining ACRYLITE® sheet. It works because of the ability of low-viscosity solvent-type cement to flow through a joint area by capillary action. Properly done, capillary cementing yields a strong, transparent joint.

Solvent cements are available from ACRYLITE® sheet distributors. They can recommend the best ones for your projects.

Before using any solvent or other type of cement, be sure to obtain and review the Material Safety Data Sheet (MSDS) for that particular product. MSDS's are available from the manufacturer. In addition, adequate ventilation must be provided and the manufacturer's guidelines for proper use should always be followed when using solvents.

To capillary cement, first make sure all parts fit together properly. Then, join the pieces together with masking tape or clamp them into a form that will support the pieces and hold them firmly in place.

When solvent cementing ACRYLITE® sheet, keep the joint in the horizontal plane and space the two edges with shims. Use .004 inch shims with sheet ¼" or thinner and .008 inch shims with sheet thicker than ¼". Insert shims every two feet for long edges.

Let the cement soak into the edges 45-60 seconds before removing the shims. At this point, the surfaces will be soft. Apply a small pressure of about 0.7 to 1.4 Ib./sq.in. (50-100 grams/sq.cm) for three minutes, until the joint is set.

If the cement does not flow completely into the joint, tilt the vertical piece very slightly (about 1°) toward the outside. This should allow the solvent to flow freely into the entire joint. Then, tilt the piece back again for a square corner.

The initial bond forms in five to ten seconds. Wait three hours before doing subsequent processing. High strength is reached in 24-48 hours. Strength will continue to build for several weeks.

Dip or Soak Cementing

Pour a moderate amount of solvent cement into a dip or soak pan. Dip the edge of one of the pieces to be joined directly into the solvent as shown. It is important that only the edge be dipped- exposing too much area to the solvent will produce a weak, slow-setting joint.

Leave the piece in the solvent 20 seconds for thin sheet and 30 seconds for relatively thick material. The time varies for different solvents and bond strength requirements-experience will help you plan the correct dipping time. Consult Roehm's technical group if you need advice.

When you remove the sheet from the cement, hold for a few seconds at a slight angle to allow excess solvent to drain off. Carefully, but quickly, place the soaked edge precisely in place on the other part to be joined. Hold the parts together for about 30 seconds without applying pressure. This will allow the solvent to work on the surface of the piece that wasn't dipped.

After 20 seconds, apply some pressure-just enough to squeeze out the air bubbles. Don't apply too much pressure as doing so will squeeze out the cement.

When pieces are joined, the part should be placed in a jig or clamp to maintain firm contact for 10 to 30 minutes. Don't allow the parts to move during this critical time.

The initial bond forms in five to ten seconds. Subsequent processing can be carried out after three hours. The bond will achieve high strength in 24 to 48 hours. Strength will continue to build for several weeks.

Viscous Cementing

Use viscous cements to join parts that can't be easily cemented by the capillary or soak solvent methods- either because the joints are hard to reach or because the edges don't fit together well. Viscous cement is thick. It will fill small gaps and make strong, transparent joints where solvent cements can't.

Viscous cements are available from ACRYLITE® distributors or on our shop. You can also make your own viscous cement by dissolving chips of clear ACRYLITE® acrylic sheet in a small amount of solvent. Let the solution stand overnight in a tightly-covered container.

Remove the masking from around the joint area and carefully apply a bead of cement to one side of the joint using a brush, spatula, or the cement applicator. Then gently join the pieces together as described under 'soak cementing.'

A solvent-resistant tape (Riveter's tape from 3M Co.) may be applied to protect the area around the joint but it should be removed carefully after about five minutes, while the cement is still wet. Don't touch the parts at all for the critical first three minutes, or the joint will not hold. The part may be carefully moved after ten minutes.

Equipment Suppliers

The suppliers listed below offer materials and equipment tested and approved by Roehm America LLC. Authorized ACRYLITE® Sheet Distributors may also offer materials and equipment.