Post-processing Guide: From Print to Perfection
20% off everything
Back to articles

Post-processing Guide: From Print to Perfection

01/11/2025
8 min
Tips and Tricks
Gloved hands sanding a 3D printed model, with post-processing tools like brushes, paints, and fillers visible in the background. Illustrating the finishing process of a 3D print.

The 3D printer has finished its work, and you hold a fresh print in your hand. Great! But if you look closely, you'll probably see visible layers, remnants of supports, or other minor imperfections. The process by which you transform this raw piece of plastic into a smooth and professional-looking object is called post-processing. And it's often what distinguishes an amateur print from a masterpiece.

This guide will walk you through the most important steps to take your prints to the next level.

1. Basic Cleaning: Removing Supports and Imperfections

The first step is always careful cleaning of the model.

  • Removing supports: Support structures are essential for more complex models, but their removal requires patience. Use small pliers, tweezers, or a scalpel. Proceed carefully so as not to damage the model itself. Gently cut off any support remnants that cannot be broken off.
  • Cleaning the surface: Remove all loose pieces of plastic, "hairs" (stringing), or other minor print artifacts.

2. Sanding: The Path to a Smooth Surface

Sanding is the most important, but also the most laborious, part of post-processing. The goal is to get rid of visible layers and create a perfectly smooth surface.

  • Start rough, finish fine: Use sandpaper with different grits. Start with coarser grit (e.g., 120-200 grit) to remove the largest imperfections and gradually move to finer grits (400, 800, 1200 grit) to achieve a smooth finish.
  • Wet sanding: For finer grits, soak the sandpaper in water. Water helps to remove dust, prevents clogging of the paper, and creates an even smoother surface. It is an ideal technique before painting.
  • Watch out for heat: Heat is generated during sanding (especially machine sanding). Materials with low heat resistance, such as PLA, can deform. Therefore, work with breaks and do not press too hard.

3. Filling and Priming: Hiding Imperfections

Even the best sanding sometimes doesn't hide all gaps between layers or small holes. This is where filler and primer come in.

  • Acrylic filler: Easy to apply, quick-drying, and sands well. It is ideal for filling smaller gaps.
  • Spray filler primer: This special type of spray paint serves as a base coat and also fills microscopic scratches and unevenness. Apply a thin layer, let it dry, lightly sand it with fine sandpaper (e.g., 800 grit), and repeat the process if necessary. Two to three layers of filler can work wonders on the surface.

4. Gluing: Joining Parts

If you are printing a large model in parts, you will need to glue them together.

  • For PLA: Cyanoacrylate (superglue) works best. For a stronger bond, you can use a spray activator.
  • For PETG and ABS/ASA: These materials can also be glued with superglue, but for a truly strong (chemical) weld, it is better to use solvent-based adhesives. For ABS/ASA, acetone works great.
  • Two-part epoxy adhesive: Offers a very strong and gap-filling bond but has a longer drying time. It is ideal for gluing large and stressed parts.

5. Painting: Final Appearance

Painting is the icing on the cake. It gives your model its final color, sheen, and a protective layer.

  1. Primer: Always start with a primer (ideally the aforementioned spray filler primer). It unifies the surface and ensures that the final paint will adhere well.
  2. Applying paint: You will achieve the best results with spray paints. Apply them in several thin layers from a distance of approx. 20-30 cm. Let the paint dry well between layers.
  3. Detail work: For details, use acrylic paints and a brush.
  4. Protective clear coat: Finally, spray everything with a clear coat (matte, semi-matte, or glossy). This protects the paint from scratches and UV radiation.

Conclusion: Patience Bears Fruit

Post-processing can be time-consuming, but the result is worth it. The ability to transform a raw print into a smooth, professional-looking object is a skill that will take your 3D printing projects to a whole new level. Whether you're making a prototype for a client, a cosplay prop, or just a model for fun, give the finishing touches the time they deserve.

Don't have time or equipment for post-processing? No problem! We can supply you with raw prints made from quality materials, ready for your own artistic finishing. Contact us and we'll discuss your project.