ABS is a common plastic found primarily in car parts and consumer products. Its chemical composition makes it a durable and inexpensive plastic that works well for injection-moulded parts. Like the majority of plastics, ABS can break when too much tension or pressure is applied. ABS responds well to solvent cements, so repairing this material is simple. Replacement parts made of ABS can be expensive. Using a few simple tools and techniques can make gluing ABS a painless experience.
Prepare the affected area. If the ABS was exposed to chemicals, such as motor oil, clean the broken piece’s edges with rubbing alcohol. Use a small artist’s paintbrush to apply the alcohol. After three minutes, wipe off the area with a rag. This removes any residual chemicals, allowing the solvent cement to penetrate the crack’s surface. Do not use solvents, such as acetone, because they can prematurely melt the surface of the ABS.
Fit the pieces together to make sure that a clean glue joint will be formed. Often, plastic will slightly distort when it breaks. If the pieces do not fit together, use spring clamps to hold them in their original position until the glue dries. The key is to have a tight glue joint when the solvent cement is applied. If the gap between the pieces being glued is wider than a business or playing card, adhere a piece of thin ABS across the crack to strengthen it. ABS can be purchased at most plastics retailers. A thickness of 0.8 mm (1/32 inch) is sufficient for this purpose.
Position the pieces to be glued so that they sit butted against one another while the glue dries. The pieces need to be held together during the gluing process, therefore, build a gluing jig to hold them in place if necessary. A gluing jig is any device that allows the pieces being glued to maintain a tight joint during the drying process. Look for household items that mimic the shape of the pieces being repaired. Plastic storage containers come in a variety of sizes and offer a 90-degree angle that makes a useful jig for gluing L-shaped parts. Round plastic containers can be used, as a collar, for holding a plastic pipe together while the solvent cement dries.
Apply a thin bead of solvent cement to one edge of the piece to be glued. Solvent cement actually fuses the ABS together by way of a chemical reaction. The ABS is melted together rather than glued together. Acrylic solvent cement forms a stronger bond than standard ABS solvent cement and should be used rather than ABS cement. Solvent cements bond very quickly, so the working time is around two minutes. Duct tape can be used as a quick way to hold pieces together while the solvent cement dries. Be careful not get glue on the tape, otherwise the tape will be permanently stuck where the solvent makes contact with it.
Place the piece without the solvent cement against the piece with the thin bead of solvent cement. Press the pieces together. Once the two pieces are aligned, let them sit for at least 30 minutes. As the reaction winds down, the leftover or residual chemicals will evaporate into the air. The bond is complete only after the residual cement has evaporated. Using too much solvent cement will result in a slowed curing time.
Use duct tape because it comes off easier and leaves less adhesive residue behind. Acrylic solvent cement comes in a medium viscosity formula, used for filling in gaps. This is the best choice for cracks that are jagged. Acrylic cement dries slower if used in cold climates. Room temperature should be around 18.3 degrees C (65 degrees F) when using this type of solvent cement. The same techniques used for acrylic apply to ABS.
Solvent cements are flammable. Do not use near an open flame.