Model-making and collecting go hand-in-hand for many enthusiasts, who often find their diecast models require intricate and painstaking work as they get older or faded. Antiques models often need to be completely restored to return the pieces to their original splendour. For diecast cars, refinishing often involves stripping away old paint and applying completely new material. To repaint your diecast model, you can use model paint found in arts and crafts stores.
Disassemble the diecast car as much as possible. Depending on the type of model you have, you may need to detach a number of screws, or use acetone or other glue solvent to remove the pieces. Disassembling the chassis, doors and other parts will allow you better access to paint all areas.
Wear protective gloves when working with chemicals. Strip away all old paint with lacquer thinner or paint stripper; soak the diecast piece for up to 30 minutes with this chemical and then scrub away old paint with a wire brush or plastic scraper.
Rinse the diecast parts in warm water to remove residual chemicals, then dry them thoroughly with a clean towel. Change your gloves so that you do not get more chemicals on the surface; if you choose not to put on a new pair of gloves, wash your hands every 10 minutes or so. The oils from your hands can change the way the paint will adhere to the diecast pieces.
Inspect the surface for any imperfections and damage; repair any damage with product-specific filler. Spread the filler into damaged areas with a putty knife. Allow all filler to dry per product instructions before continuing.
Sand the entire surface of the diecast model with 400-grit sandpaper. This will even any repair work with the rest of the vehicle and make the surface more accepting of the paint.
Use painter's tape or masking tape to mask off any areas that you do not want painted. Spray a thin layer of primer onto the surface and allow it to dry for an hour. Apply a second layer of primer and allow it to dry for another hour before continuing.
Gently sand the surface again with 400-grit sandpaper to prepare the surface. Apply a thin layer of topcoat model paint to the diecast and allow it to dry completely (this generally takes at least an hour). Sand again with 400-grit sandpaper and apply a second coat. Repeat the drying and sanding process for three coats and allow the third coat to dry completely.
Inspect the dry car. Apply more layers of paint or touch-ups as necessary. Allow the diecast model to dry for 24 hours before removing tape and reassembling it.
Model paint comes in spray or liquid forms. If you are using a liquid version, consider purchasing an air gun to apply smooth, even coats of the paint to your diecast model. Depending on your chose paint product, the colour of your primer can affect the final colour of your overcoat paint. Choose your product and colour carefully. Find materials for this project at automotive stores, model shops, and arts and crafts retailers.
Some paint strippers can melt plastic, but are safe for use on metal. Be sure you know the material of your car and use materials appropriate for the diecast.