How to Sand Miniatures: A Complete Guide to Smooth Finishes

Before you start painting a miniature, it’s worth spending a little time on the cleanup. Small imperfections like mold lines, sprue marks, and rough edges can easily stand out once the paint goes on.

A few simple sanding steps can make a big difference, giving your miniature a smoother surface and helping the paint adhere better. In this guide, we’ll look at how to sand miniatures, from choosing the right tools to getting a clean finish.

Why Sanding Miniature Is an Essential Step Before Painting

Before you reach for your primer, your model needs a clean canvas. Without proper surface preparation, even small imperfections can become much more noticeable once the paint goes on.

Removing Mold Lines for Better Paint Adhesion

When manufacturers create plastic or resin kits, liquid material is injected into two-part steel molds. The seam where the mold halves meet leaves a small ridge known as a mold line. Along with sprue marks, these imperfections are common on helmets, weapons, armor plates, and other detailed areas.

Removing these imperfections before painting offers several important benefits:

• Removing Injection Imperfections: Careful trimming and sanding eliminate mold lines and sprue marks, creating a cleaner surface before priming.
• Preventing Paint Pooling: Dark washes and contrast paints tend to collect along raised ridges, making mold lines much more noticeable after painting.
• Improving Primer Adhesion: Light sanding reduces the overly smooth surface of plastic miniatures, helping primer and base coats adhere more evenly and improving durability during handling and gameplay.

Essential Tools for Sanding Miniature Models

You don't need a toolbox full of equipment to get started with miniature sanding. With a few essential tools, you can handle most common cleanup tasks and create a much better surface for painting.

Tool	Primary Function	Best Used For
Hobby Nippers	Cutting parts off sprues	Initial part removal and clean plastic cuts
Hobby Knife	Removing sprue nubs and mold lines	Precise detail cleanup
Sandpaper / Sanding Sponges	Smoothing surfaces (400–1200 grit)	Flat surfaces and curved miniature details
AB Putty / Fillers	Filling gaps and repairing damage	Fixing gouges and smoothing joints

Once you know which tools to use, the next step is understanding how different miniature materials respond to sanding. Plastic, resin, and metal each require a slightly different approach.

Understanding Different Miniature Materials Before Sanding

Not all miniatures are made from the same material, and each one behaves a little differently when you start cutting and sanding. Understanding these differences helps you avoid damaged details and choose a better approach for each model.

Material	Common Uses	Key Characteristics	Sanding Approach
Injection Plastic	Warhammer sprues, scale model kits	Soft, flexible, and forgiving	Easy to trim and smooth with hobby knives and sandpaper
Resin / GK Kits / 3D Prints	Garage kits, resin figures, printed miniatures	Harder, brittle, produces fine dust	Requires gentle handling and careful sanding
Metal	Pewter and white metal miniatures	Dense, heavy, and durable	Often requires files for shaping and cleanup

Key considerations for each material:

• Plastic (Polystyrene): The most common material for tabletop miniatures. It is easy to cut and sand, but avoid excessive pressure or high-friction tools, as heat can soften or damage the surface.
• Resin & 3D Prints: Resin can produce fine dust during sanding, so proper protection is important. Wear a dust mask when needed, keep your workspace ventilated, and consider wet sanding to reduce airborne particles.
• Metal Miniatures: Metal is harder than plastic and requires more effort during cleanup. Needle files are often more effective than soft sandpaper when shaping edges or removing excess material.

Step-by-Step Guide to Sanding Miniatures

Before the first coat of primer goes on, it is worth spending some time cleaning up the miniature properly. A few careful sanding steps can remove distracting imperfections and give you a much cleaner surface to work with.

Removing Parts Using the Two-Cut Method

Avoid cutting a part directly against the sprue frame in one step. The pressure from nipper blades can stress the plastic, leave visible white stress marks, or gouge into the miniature surface.

The two-cut method gives you much better control:

• First cut: Place your hobby nippers on the sprue runner and leave around 0.5 cm of extra plastic attached to the part.
• Second cut: After removing the part from the frame, trim the remaining plastic closer to the surface, leaving a small 1–2 mm nub for final cleanup.

Leaving a small amount of excess material is safer than cutting too close and accidentally removing part of the miniature itself.

Trimming Sprue Marks with a Hobby Knife

After removing the part, use a sharp hobby knife to clean up the remaining 1–2 mm sprue nub and any raised mold lines.

Avoid trying to remove the entire nub with one heavy slice. Instead, hold the blade firmly and use light, controlled scraping motions to shave away thin layers of plastic. This approach helps preserve small sculpted details while preparing the surface for sanding.

Sanding Miniature Surfaces from Coarse to Fine Grits

After trimming, sanding helps blend the repaired area back into the surrounding surface and creates a smooth finish ready for priming.

A gradual grit progression works best. As a general rule, increase the grit by roughly 200 steps between sanding stages to remove scratches from the previous layer:

• 400–600 grit: Remove remaining sprue marks, heavy mold lines, and uneven areas.
• 800 grit: Smooth scratches left by coarser sanding.
• 1000–1200 grit: Refine the surface and prepare it for primer.

Use light pressure throughout the process. Aggressive sanding can flatten small details or create unwanted changes to the miniature’s shape.

Wet Sanding vs. Dry Sanding

Wet sanding involves using water with sandpaper or sanding sponges while working on the surface. The water helps reduce dust, prevents abrasive materials from clogging, and allows the sanding surface to work more smoothly.

Wet sanding is especially useful for:

• Resin miniatures and 3D-printed models, where sanding can create fine dust particles.
• Large smooth surfaces, such as armor panels, where a cleaner finish is needed.
• High-grit sanding, where reducing surface scratches is important.

For most plastic miniatures, traditional dry sanding is usually sufficient, especially during early cleanup stages.

Cleaning Dust and Inspecting the Surface

After sanding, remove leftover dust with a soft brush or rinse the miniature with clean water if needed. A clean surface allows primer and paint to adhere more evenly.

Before moving on to priming, inspect the miniature under good lighting. Run your finger or fingernail gently across the sanded area—if you can still feel an edge or raised section, give it another light pass with a finer grit.

A properly cleaned and smoothed miniature provides the ideal foundation for painting.

How to Fix Mistakes When Sanding Miniatures

Even experienced hobbyists occasionally cut too deep, remove too much material, or damage a small detail during sanding. Fortunately, most sanding mistakes are easier to fix than they first appear.

Repairing Over-Cut Areas with AB Putty

For deep cuts, gouges, or areas where too much material has been removed, AB putty (epoxy putty filler) is a simple way to rebuild damaged areas and restore the surface:

• Mix the putty: Combine component A and component B in a 1:1 ratio, then knead thoroughly until the color and texture become completely uniform.
• Apply the putty: Press the mixed AB putty into the damaged area and shape it slightly above the surrounding surface.
• Allow it to cure: Let the putty fully harden according to the manufacturer's instructions before sanding.
• Smooth the repair: Sand the repaired area gradually from medium to fine grits until it blends with the original surface.

AB putty can be shaped, carved, and sanded after curing, making it useful for rebuilding damaged areas and restoring the original shape of the miniature.

Restoring Lost Details and Surface Texture

Heavy sanding can sometimes soften small details such as panel lines, armor edges, or textured surfaces. In these cases, you can carefully recreate the missing details before priming:

• Choose the right tool: Use a dedicated scribing tool or panel liner to restore softened panel lines, sharp edges, and surface details.
• Work slowly with light pressure: Guide the tool along the original path using several light passes instead of forcing a deep cut in a single stroke.
• Follow the original contours: Match the shape and direction of the sculpted lines so the repaired details blend naturally with the surrounding area.

Miniature Sanding Safety Tips and Best Practices

After all the careful sanding and cleanup, it is worth taking a moment to protect yourself and your workspace. A few simple habits can help reduce dust, prevent accidents, and keep miniature preparation enjoyable.

Protecting Yourself from Plastic and Resin Dust

Fine particles from sanding should be avoided, especially when working with resin miniatures and 3D-printed models. Resin dust can become airborne easily and may irritate your lungs and eyes.

• Wear proper protection: Use an N95 or P2 particulate mask when sanding resin models.
• Improve ventilation: Work in a well-ventilated area to reduce dust buildup.
• Consider wet sanding: Using water with your sanding materials helps trap particles and reduces airborne dust.

Safe Handling of Hobby Knives and Sharp Tools

Sharp tools are essential for miniature cleanup, but they should always be handled carefully:

• Cut away from yourself: Keep the blade pointed away from your fingers and body while trimming.
• Replace dull blades: A worn blade requires more pressure and is more likely to slip.
• Dispose of sharp waste safely: Keep a small container nearby for used blades and sharp sprue scraps.

Start with a Better Surface

A great paint job starts long before the first brush stroke. Taking time to remove mold lines, smooth imperfections, and prepare your miniature properly creates a cleaner foundation for every layer of primer and paint.

Whether you are working on plastic, resin, or metal miniatures, the key is patience and control. Use the right tools, sand gradually, and enjoy the process of turning each model into a finished piece you can be proud of.