Polishing the Sinanju: a builder's guide to the MG kit's mirror finish

The Master Grade Sinanju has earned its reputation as one of the most striking mobile suits in the Gunpla catalogue, largely thanks to the gleaming chrome-style parts that dominate its frame. That same shine, however, is also what gives many first-time builders nightmares, since fingerprints, scratches, and cloudy patches can appear before the kit is even fully snapped together.

Before diving in, it helps to understand that the Sinanju's silver components are not actual metal plating but treated ABS and polystyrene pieces with a high-gloss mould finish. Knowing this changes how you approach every step, from cutting parts off runners to applying the final coat, which is why experienced Sydney, Melbourne, and Brisbane modellers tend to follow a careful workflow.

Why the Sinanju's finish is uniquely tricky

The moulding process used for these parts creates a reflective surface that is also softer than standard coloured plastic. Every time you handle a runner with bare fingers, natural oils transfer onto the gloss and leave surprisingly stubborn marks. The Sinanju concentrates these shiny parts in highly visible areas, including the chest, shoulders, and inner leg frame.

Australian weather adds another layer of complexity. Humid Brisbane summers, dry Perth heatwaves, and a cool Melbourne winter each influence how top coats cure and how static builds up on the bench. A finish that cures perfectly in an air-conditioned Sydney apartment may behave very differently in a tin-shed Adelaide garage during summer.

Australian Consumer Law covers replacement kits that arrive with scratched chrome parts through Australia Post, so it is worth photographing the box as soon as it is delivered and noting any damage straight away. Documenting issues at the front end streamlines exchanges with retailers, whether the seller is a local store in Parramatta or a national mail-order house in another state.

Setting up a workspace that protects the chrome

A clean bench is essential when working on this kit. Dust, pet hair, and stray fibres show against a mirror surface the moment parts leave the runner, which is why many Australian builders lay down a lint-free cloth or butcher's paper before starting. Daylight-balanced LEDs reveal small scratches far better than the warm bulbs common in older workshop setups.

If your collection has outgrown your free time, organising your backlog and workspace before committing to the Sinanju is well worth the effort. Builders in Hobart and Canberra often carve out a single Saturday morning, with the door closed, to focus on chrome-heavy kits. Cotton or unpowdered nitrile gloves should sit on the bench from the moment you open the box, and cheap pairs are stocked at Bunnings, chemists, and most servo suppliers.

Handling the bare chrome parts

The single biggest mistake is removing parts from the runner with bare hands. Cut close to the gate but leave a millimetre, then trim with a sharp Godhand or Tamiya side cutter to avoid stress marks. Any roughness at the gate will wear through the gloss and create a dull halo around the contact point.

Another worthwhile habit is to assemble chrome components last. Fitting them earlier exposes them to clamping, masking, and accidental knocks from other tools. Saving the silver parts for the final hour gives a clean window to seat everything, the same sequence followed at the IPMS shows in Brisbane and the monthly meet-ups in Melbourne.

Top coat options and how they compare

A clear top coat locks in the shine while adding a thin protective layer, but the choice of product changes the look and feel considerably.

For most Sinanju builders, a gloss acrylic clear sprayed in thin, dust-free passes delivers the best balance. Aerosol cans are easier to source from Australian retailers such as Hobby Warehouse and Metro Hobbies in Sydney than airbrush-ready bottles for newcomers. A cardboard box laid on its side, with the front cut away, doubles as a cheap spray booth for any builder in a garage or carport, and it blocks enough breeze to let coats flash off cleanly.

Panel lining, detail work, and avoiding pitfalls

The gold piping along the Sinanju's skirt armour and the recessed details of the inner frame look superb against the chrome, but panel lining fluid can stain glossy plastic if left to pool. Thin washes, applied with a fine brush and wiped away almost immediately, prevent the capillary action from drawing enamel into areas it shouldn't be.

The MG Sinanju Stein review walks through how Bandai kept panel lines crisp on chrome surfaces. The lessons transfer directly to the standard Sinanju, especially around the ankles and chest vents where the gold trim meets the silver frame.

Cloudy patches from skin oils usually lift with a gentle wipe using a microfibre cloth and a touch of isopropyl alcohol. Light surface scratches sometimes buff out with Novus 2 applied in straight strokes rather than circles. Leaving protective film on chrome parts too long is another common trap; the adhesive can ghost into the surface under Australian summer sun and leave a dull rectangle that no amount of polishing will remove.

Recommendations for a stress-free chrome build

Treat the Sinanju as a two-stage project, with matte and coloured sections completed first and chrome reserved for a dedicated finishing session. This approach builds muscle memory on the less risky parts, then commits the chrome to a calmer frame of mind once the rest of the model is finished. Pair the session with the right tools and the kit will reward the patience.

• Wear clean cotton or nitrile gloves whenever you touch a shiny part, from runner to final placement.
• Apply two to three thin passes of gloss clear coat rather than one thick wet coat that can flood detail.
• Build the chrome components last, after all painting, masking, and sanding on surrounding parts is finished.
• Keep a dedicated microfibre cloth and a small bottle of plastic polish within arm's reach for quick fixes.
• Photograph the kit under different light sources before sealing the finish, since daylight often reveals what desk lamps hide.

For builders who want a deeper comparison of how different premium grades handle their finishes, the RG Build Strike Full Package review offers a useful counterpoint to the Sinanju's heavy chrome. Share your finished build in the Display Case once the last piece is seated, and let the community see how the mirror finish turned out under Australian light.