Q&A for How to Reinforce Plastic

Use a heat gun to mold it to the required shape (hairdryers do not give off enough heat). You can also sandwich the shaped plastic between a folded sheet of foil and iron the foil to heat up the plastic. The foil will not stick as long as the plastic does not melt completely. Start at the wool setting, and slowly increase the iron temperature until the plastic feels warm. Overheating will melt the plastic. Allow it to cool completely before use.

Cheese cloth with plaster is a good material to reinforce a plastic mask. It is found in hobby model making for creating hills in scenery. The cloth is moistened and can then be shaped onto any surface. Some glue can be add to make it stick to the plastic. Casting resin has a lot of chemical solvent and tends to fill in a cavity and not take on a special shape (unless it is in a mold). Several coats of clear acrylic spray can provide added strength. Make sure to let each layer dry between coatings to get the best result.

An industrial strength glue like E6000 will work best. It is clear and designed to hold well over a wide range of materials. Clean both surfaces before applying a thin layer of glue. If it is runny, let it get tacky before pressing the two surfaces together, Allow it to dry completely before putting any stress on the repair. Construction adhesive is another option for a fast fix however, it has color to the glue.

Consider using epoxy resins to make it rigid, though they can be challenging to fill in a horizontal tube due to their watery consistency. For adhesion to a vinyl dashboard, use a 2-part adhesive designed for plastics, like those from Loctite. Silicone is another option for bonding the tubing, providing stable adhesion.

To reinforce the brush handles, you can glue wooden dowel rods to them using an epoxy cement made for plastic bonding. For a hollow handle, drill a hole slightly bigger than the dowel, inject the epoxy, and insert the dowel. For an I-beam shaped handle, attach a dowel to both sides. Let the epoxy cover the dowel ends to avoid water absorption.