Weld-On 3 is a water-thin, non-flammable cement formulated to quickly develop high strength, clear bonds to many thermoplastic substrates, particularly acrylic. The bond is achieved by first softening the surfaces to be joined and then fusing them together with dissipation of the solvent. The initial bond forms within a few minutes and quickly increases in strength. Substantial strength will be obtained within only a few hours. Under certain conditions, especially with high humidity, a white mark on the plastic (commonly called blushing) may sometimes be encountered. Where a more blush resistant cement and longer open time is required, Weld-On 4 is recommended.

Substrate Recommendations

Weld-On 3 is formulated for cementing acrylic (poly-methyl methacrylate) plastic to itself. It is not recommended for cross-linked acrylic.

Bonding Recommendations

Weld-On 3 is used extensively in sign fabrication. Strong butt joints are made with flat sheets by using the soak method for such applications as cementing letters to acrylic panels. Butyrate trim-capping of acrylics is another highly recommended use for Weld-On 3. It is also widely used in the POP industry (e.g. display), and in the fabrication and bonding of plastic containers, housewares, bottles and many other applications using the capillary method.

Additional Information

This product is not for general consumer use. It is an industrial product intended for professional use only. Plastic-Craft Products reserves the right to substitute similar quantity Weld-On 4SC for Weld-On 3 or Weld-On 4 when ordered by an individual consumer.

This product may not be shipped into Los Angeles, San Bernardino, Orange, or Riverside Counties. Plastic-Craft Products reserves the right to substitute Weld-On 4SC for Weld-On 3 or Weld-On 4 when ordered for delivery to zip codes in those counties.

Directions for Use

General: Surfaces to be joined must be clean, dry, and fit intimately without forcing. Apply cement with syringe, eyedropper or brush. Assemble while parts are still wet. If cement is applied to one surface, let the two surfaces be in gentle contact for a few seconds to allow the cement to soften the dry surfaces, then press parts together in firm contact. Initial bonds form very quickly. 65 – 80% of the ultimate bond strength will be obtained within 24 hours. Strength will continue to increase for several weeks.

Capillary Method: Parts are placed lightly together and cement is applied to the edge of the joint with syringe or eyedropper. By capillary action, the cement will flow a considerable distance, approximately 0.25 inch (0.64 cm), between two such surfaces. Allow a few seconds for the cement to soften the surfaces. Press parts firmly together.

Soak Method: Vertically dip surfaces until softened (approximately 2 to 5 minutes), then join pieces firmly together.

• In many cases, this cement dries too fast to apply by brush to the parts before they are joined.
• If crazing is a problem, we suggest you consider annealing before cementing.

Shelf Life

Two years in tightly sealed containers. The date code of manufacture is stamped on the bottom of the container. Stability of the product is limited by the evaporation of the solvent when the container is opened. Evaporation of solvent will cause the cement to thicken and reduce its effectiveness. Adding of thinners to change viscosity is not recommended and may significantly change the properties of the cement.