Reviving Plastic Models: A Restoration Guide

It might come as a surprise, as it did to Rod, the extent of flash, mould lines, and sink marks that can remain on plastic model parts, often left untreated from their initial assembly. This is a common characteristic of older kits, harking back to a time when the focus was more on quick assembly and painting rather than the meticulous preparation we often strive for today. However, what's truly remarkable is the surprising level of detail present in these vintage kits, especially considering the limited technology available during their production. Restoring a plastic model is not only possible but can be an incredibly rewarding experience, allowing you to appreciate the craftsmanship of yesteryear with a renewed aesthetic. This guide will walk you through the essential steps and considerations for bringing your beloved plastic models back to their former glory.

The Importance of Preparation

Much like assembling a brand-new kit, the preparation phase for a model restoration is paramount. This involves a thorough inspection of all components to identify any areas that require attention. You may find yourself needing to drill out broken pegs or holes that were either missed during the original build or have deteriorated over time. Similarly, replacing broken pegs is a common requirement. This can be achieved by using small lengths of plastic rod or wire, carefully trimmed to size and inserted into the damaged area.

Tackling Flash, Mould Lines, and Sink Marks

These imperfections are a hallmark of older injection moulding processes. Flash refers to excess plastic that has squeezed out between the mould halves. Mould lines are the faint ridges left where the mould halves met. Sink marks are small indentations on the surface, often appearing near thicker parts where the plastic has cooled and contracted. All of these can be addressed with patience and the right tools:

• Flash Removal: A sharp hobby knife, such as a Tamiya or X-Acto knife, is your primary tool here. Carefully shave away the excess plastic, taking care not to cut into the main part of the model. For stubborn flash, a small file or even fine-grit sandpaper can be used.
• Mould Line Smoothing: Gently scrape along the mould line with the back edge of your hobby knife or a dedicated mould line remover tool. Follow this with progressively finer grits of sandpaper (e.g., 400, 600, 800, 1000 grit) until the line is no longer visible and the surface is smooth.
• Sink Mark Filling: Small sink marks can often be filled with a small amount of putty, such as Tamiya Putty or Milliput. Once dry, sand the area smooth. For deeper sink marks, you might need to apply putty in layers, allowing each layer to dry before sanding.

Repairing Broken Components

Broken parts are a common issue with older models. The key to successful repair lies in creating a strong bond. For simple breaks, plastic cement, such as Tamiya Extra Thin Cement or Revell Contacta Professional, is usually sufficient. Apply the cement to the broken edges and hold them firmly together until the bond sets.

Reinforcing Stub Axles

A particularly common area of fragility in many models, especially vehicle kits, is the stub axle. These small, often thin, protruding parts are prone to breaking. Restoring them involves not only reattaching a broken piece but potentially creating a new, stronger one.

If a stub axle is broken off, the process for repair can be as follows:

1. Create a New Stub Axle: Cut a new stub axle from plastic rod of a suitable diameter. The diameter should match the original part as closely as possible.
2. Drill for Reinforcement: Carefully drill down the centre of both the existing axle case (or kingpin housing) and the new stub axle. The hole should be deep enough to provide a good anchor point for the reinforcing rod.
3. Insert Reinforcement: Cut a small length of rod or fuse wire. This will act as an internal support. Glue this rod or wire into the pre-drilled holes, ensuring it bridges the gap between the axle case and the new stub axle. Plastic cement or a cyanoacrylate (super glue) can be used for this. The wire provides crucial reinforcement, significantly reducing the likelihood of future breaks.

This method ensures a durable repair that can withstand the stresses of handling and display.

Addressing the Headlamp Reflector Bowl

The headlamp reflector bowl is another detail that can often be improved during a restoration. In many older kits, these may be moulded in clear plastic but lack any reflective quality, or they might be moulded in opaque plastic. Here’s how to enhance them:

• If moulded in clear plastic: You can carefully paint the inside of the bowl with a metallic paint, such as silver or chrome. This will create a reflective surface. Alternatively, you can use a specialist chrome foil or decal designed for this purpose.
• If moulded in opaque plastic: You will likely need to paint the inside of the bowl. A good quality metallic silver or chrome paint will work best. For a more professional finish, consider using a silvering solution on the inside surface before applying the metallic paint.

The goal is to simulate the reflectivity of a real headlamp, adding a significant touch of realism to the model.

General Assembly and Finishing Touches

Once all the individual parts have been cleaned, repaired, and prepared, the assembly process can begin. Use your preferred plastic cement, applying it sparingly to ensure clean joints. For very small or delicate parts, a fine-tipped applicator or a syringe can be useful.

Sanding and Priming

After the main assembly is complete, a final sanding may be necessary to smooth out any glue marks or minor imperfections. Apply a primer coat. This serves several purposes: it reveals any remaining flaws that need further attention, provides a uniform base colour for your paint, and helps the subsequent paint layers adhere better. Acrylic primers are popular due to their quick drying times and low odour.

Painting and Decals

Painting is where your restored model truly comes to life. Whether you're using a brush or an airbrush, aim for thin, even coats. Allow each coat to dry thoroughly before applying the next. Once the base colours are applied, it's time for decals. Older decals can sometimes be brittle, so handle them with care. Applying a gloss varnish before decals and a satin or matte varnish afterwards can help them to blend seamlessly with the model's surface.

Frequently Asked Questions

Q1: Can I use super glue to assemble a plastic model?

While super glue (cyanoacrylate) can be used for certain repairs, especially where plastic cement might not be suitable or for attaching parts made of different materials, it's generally recommended to use plastic cement for the main assembly of plastic models. Plastic cement chemically welds the plastic parts together, creating a stronger, more integrated bond than adhesive glues.

Q2: How do I deal with very old, brittle plastic?

Old, brittle plastic requires extra care. Avoid forcing parts. If a part is very stiff, you might try gently warming it with a hairdryer on a low setting to make it slightly more pliable. For repairs on brittle plastic, consider using a slower-setting adhesive like CA glue with an accelerator, or a two-part epoxy, as these can offer more control and less stress on the material compared to fast-acting plastic cements.

Q3: What is the best way to remove old paint from a model?

Several methods can be used, depending on the type of paint and the plastic. For acrylic paints, isopropyl alcohol (rubbing alcohol) can often be effective. For enamel paints, specialist paint strippers designed for plastic models are available (always test on a spare piece of sprue first). Oven cleaner can also be surprisingly effective for removing stubborn paint, but again, test its effect on the plastic first, as some cleaners can damage it. Always work in a well-ventilated area and wear protective gloves and eyewear when using paint strippers.

Q4: How can I improve the detail on an old model?

Beyond cleaning and surface preparation, you can add new details. This might involve adding wire for brake lines or fuel pipes, using thin strips of plastic for panel lines, or even scratch-building entirely new components if the originals are too poor or damaged. Referencing period photographs or the original kit instructions can provide inspiration for adding or correcting details.

Conclusion

Restoring a plastic model is a journey that connects you with the history of the hobby and the evolution of manufacturing techniques. By understanding and applying the principles of preparation, repair, and careful finishing, you can transform a forgotten relic into a cherished display piece. The satisfaction of bringing an old kit back to life, with all its inherent charm and surprising detail, is a reward in itself. So, don't hesitate to delve into your collection and give those older models the attention they deserve – you might be surprised at the results!