Gluing plastic with Weldon Cement

Solvent welding acrylic plastic takes place is sign & display companies all over Ireland.

Hand in glove with acrylic plastic goes Weldon acrylic cement.

Weldon cement has been used for decades, for the efficient bonding of a whole range of plastics, and are the optimum glues for gluing acrylic plastic both to itself and a huge range of other plastics such as acrylic, butyrate and polycarbonate.

It this piece, we go through the optimised method for gluing plastics with Weldon 4SC & Weldon 16.

Prepare the pieces to be joined by cutting the acrylic. Pieces which are 6.3 mm or thicker, are best cut with a table saw. Pieces that are thinner than this can be scored with a scalpel, then snapped cleanly apart, but only along straight lines.

Ensure that the edges of the acrylic are perfectly flat and free of bumps or cuts. Depending on the glue type, acrylic cement has little to no gap filling properties. Abrading the edges with  P180 sandpaper is suggested. Sand along the edges to be joined to ensure that the edges are perfectly smooth and square. Do not sand the edges so that they become round. Try using fine sandpaper on a flat surface to ensure a flat, square result.

Working on a level table, assemble  the acrylic in preparation  for gluing. Before gluing them, test fit them together as they will be joined. After ensuring a snug fit, secure the pieces together with either masking tape or clamps, or tack them together with Scigrip CA41 adhesive & A113 activator.

Weldon 4SC is water thin, blush resistant cement for gluing all types of acrylic excluding cross-linked acrylics. As it is water thin, the glue is typically applied with a syringe with the associated applicator tip. Using the syringe, apply a small amount of the solvent cement to the joint between the 2 acrylic pieces; it will wick into the joint itself through capillary action. Never attempt to apply Weldon 4SC to the pieces separately and then press them together. Weldon 4SC begins to set within seconds, so this method will produce a weaker joint. It will also increase the risk of drips, which will melt and deform any acrylic it touches. Allow the glue to set for several hours. After it has set, remove the clamps or tape and use a fine-grit sandpaper to sand any rough patches of adhesive smooth.

Weldon 16 is thicker than Weldon 4SC, and very suitable for gluing applications where fast cure is needed, for example, gluing large signs, plastic letters and display units. For use, the Weldon 16 is applied to either one or both sides of the plastic. The two surfaces are brought together and held or clamped  for a few minutes. Jobs done!

Both Weldon 4SC & Weldon 16 are supplied in handy 473 ml tins and are available from stock. We also stock a large range of syringes and applicator tips. Don’t hesitate to contact us for the best glue advice in Ireland.