How to clean and prep 3D printed terrain - A complete guide

Keywords: 3D printed terrain, terrain for Warhammer game, Warhammer 40K like scenery, PLA terrain prep, painting wargaming terrain, 3D print cleanup, tabletop terrain tips

You've got your 3D printed wargaming terrain in front of you - whether it's a ruined building for Warhammer 40, a gothic archway for Age of Sigmar, or a dark dungeon tile for your next RPG session. It looks great. But should you just prime it and start painting? 

Not quite. A few well-chosen prep steps will make a massive difference between a result that looks "printed" and one that looks like it belongs on a professional gaming table.

In this guide, we walk you through every technique worth knowing - from the quick and essential ones to the more advanced fixes - so you can diagnose exactly what your terrain needs and apply the right solution. No wasted time, no guesswork.

At Voidborn Prints, we meticulously tune our printers and apply efficient methods to remove stringing before shipping, ensuring each terrain piece boasts a very good initial finish. However, as with all FDM 3D printing, certain inherent imperfections can still occur. A little extra prep on your end will always elevate your final result, transforming a great print into a masterpiece for your wargaming table.

First: Diagnose your piece

Before reaching for any product, take a good look at your terrain piece in good lighting. Here are the most common issues you might spot - and the sections of this guide that address each one:

Your prep toolkit - What you might need 

Not every piece needs every product. Below is a checklist, sorted from essential to situational. Check off what applies to your situation.

Essential (Every terrain piece)

• Small butane torch or heat gun
• Stiff-bristled brush or old toothbrush
• Filler primer spray designed for 3D prints (Greenstuff World, AK Interactive, ...)

Common (Most pieces will benefit)

• Super glue (thin viscosity / CA glue)
• Food-grade baking soda 
• Wet & dry sandpaper (400 to 800 grit)
• Craft knife / scalpel with fresh blades

Situational (For specific problems)

• Two-part epoxy putty (Green stuff or Milliput)
• UV Resin + UV lamp

Technique 1 - Remove stringing with a heat source

Priority: HIGH - Do this first, every time. 

What it fixes: Those thin, spiderweb-like filament hairs that appear between parts of your terrain. At Voidborn Prints, we're treating every piece like this before shipping.

What you need: A small butane torch (the type used for crème brûlée works perfectly) or a heat gun on low.

How to do it:

1. Hold the piece at arm's length.
2. Pass the flame or heat quickly and continuously across the surface - never stop moving.
3. Work section by section, 3-5cm from the surface.
4. The stray filaments will vanish in seconds without affecting the underlying detail. 
5. Pass your fingers through the print to remove blobs formed by burnt filament.

Pro tip: Work in a well-lit area and rotate the piece to catch all angles. What looks clean from one direction may have stringing on the opposite side.

Never hold the heat in one spot. PLA has a relatively low melting point. Hovering too long - even a second or two - can soften or warp fine details on your new terrain.

Technique 2 - Apply filler primer designed for 3D Prints

Priority: HIGH - Almost non-negotiable for any painted terrain.

What it fixes: Residual fine layer lines, microscopic surface pores, and uneven surface texture. A standard spray primer will work, but a filler primer formulated for 3D prints fills surface imperfections that regular primer simply coats over.

Recommended products: Greenstuff World spray filler primer, AK Interactive Microfiller primer spray.

Before / after applying one coat of filler primer on a PLA printed terrain

How to use: 

1. Make sure the surface is clean and dry before spraying.
2. Shake the can vigorously for at least 60 seconds.
3. Spray from 25-30cm away in thin, sweeping passes. 
4. Allow each coat to dry fully (15-30 minutes) before applying the next. 
5. Two to three light coats will always outperform one heavy coat.

Pro tip: Before applying another coat, you can lightly sand the flat surfaces of your print. It'll greatly improve its look in the end.

Critical warning for miniature painters: These filler primers are formulated specifically for hard terrain surfaces and 3D printed PLA. Do NOT use them on your miniatures - whether resin or plastic. The propellants and filler agents will obscure fine facial details and armour etchings on 28mm figures, and can damage certain resin materials. For miniatures, stick to dedicated miniature primers: Vallejo Surface Primer, Warhammer Chaos Black, Army Painter sprays, and similar products.

Technique 3 - Sand away layer lines (wet sanding)

Priority: MEDIUM - High - Worth it on visible, flat surfaces.

What it fixes: Visibile horizontal lines on large flat surfaces like walls, floors, or flat rooftops. Less useful (and potentially damaging) on detailed or textured surfaces, where the filler primer is a better choice. 

What you need: Wet & dry sandpaper - start at 400 grit for noticeable lines, finish at 600-800 grit for a smooth surface. A small bowl of water.

How to do it: 

1. Wet the sandpaper in water before use. This prevents static dust and reduces the risk of scratching. 
2. Sand in circular motions on flat surfaces, applying gentle, even pressure.
3. Move from coarser to finer grit progressively. 
4. Wipe clean between grits.

Pro tips:

• Don't sand directly over textured areas (stone, brick, wood grain patterns) - you'll obviously flatten the details. Reserve sanding for smooth panels and flat joins only. 
• You can mix this with Technique 2 by applying filler primer and sanding after. It'll give you an almost perfect result. You can then use your favourite primer for painting. (click here for a painting guide we wrote some time ago)

Technique 4 - Fill small gaps with super glue + baking soda 

Priority: SITUATIONAL - Quick and cheap, impressive results.

What it fixes: small cracks between assembled parts, surface pores, and shallow layer lines on flat surfaces. Perfect for terrain walls, floors and any large flat panel you want to look clean under paint.

What you need: Thin (low-viscosity) super glue, food-grade baking soda.

How to do it:

1. Apply a small drop of thin super glue into or along the gap.
2. Immediately sprinkle a tiny pinch of baking soda directly onto the glue.
3. It reacts and cures in 2-5 seconds, creating a hard, sandable filler.
4. Let it sit for 30 seconds, then file or sand to blend it into the surrounding surface.

Pro tip: Less is more. A small drop of glue + a light dusting of baking soda is enough for most gaps. Too much creates a lumpy white residue that takes more work to sand down than the original gap.

Technique 5 - Fill large voids with putty or UV resin

Priority: SITUATIONAL - For significant gaps or missing areas only. 

What it fixes: Larger gaps between assembled sections, warped joins, or voids that the super glue method can't fill cleanly. This does not come up with every piece, but when it does, you need something with body. 

 Option A - Two-part Epoxy putty (Green Stuff / Milliput) 

• Mix equal parts of both components until the colour is uniform. 
• Press into the gap with a sculpting tool or a wet finger.
• Smooth the surface and leave to cure overnight.
• Once fully cured, sand and prime as normal.

Green Stuff stays rubbery when cured and is great for curved or organic shapes. Milliput cures harder and sands more cleanly - better for flat architectural surface on buildings and ruins.

Option B - UV Resin

• Wear gloves (uncured UV resin is a skin irritant). 
• Apply directly into the gap with the nozzle or a toothpick.
• Cure for 30-60 seconds under a UV lamp. 
• Sand when cured.

UV resin is faster and cleaner than putty for small horizontal gaps. The downside is that it requires a UV lamp, it can be messy to apply and it doesn't work as well for thick fills. 

Technique 6 - Clean up print artefacts with a craft knife

Priority: MEDIUM - Fast and effective for blobs and rough edges.

What it fixes: Blobs of excess material, "elephant foot" (the slight flare at the base of a print), rough overhangs, and leftover support attachment points.

What you need: A craft knife with a fresh blade. A blunt blade tears rather than cuts - always work with a sharp one.

How to do it: 

1. Hold the piece firmly on a stable surface.
2. Use the blade at a low angle (~30°) to shave off blobs or ridges - never stab or pry. 
3. For support attachment points, gently scrape until flush with the surface. 
4. Follow with a light sand if needed.

Pro tip: a sharp blade does 90% of the work. Replace blades regularly - a fresh blade is far safer and more precise than a worn one.

What NOT to do on PLA - Common mistakes that damage your terrain 

We hope this guide helps you get the best possible result from your terrain - whether it's from Voidborn Prints or printed at home. These are the exact techniques and products we trust ourselves, and the difference they make on a Warhammer table (with highly detailed minis) is very real. 

If you have any questions, or if you want to share photos of your painted scenery, we'd love to hear from you. The community is what makes this hobby great. 

Happy hobbying - And may your battles look as epic as they play!