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3D Print Post Processing

Updated: Feb 25, 2020

Removing layer lines for a glossy smooth finish.

Your 3D models come ready-to-wear, but for that extra bit of polish you can follow the steps below to get a film-quality finish.


Why do 3D prints have lines?

3D printers create their objects through layers. A 3D shape is split into thousands of flat designs which will slowly print on top of itself to create the final model. The thickness of each layer is referred to as the "layer height". Layers are present in all 3D printing, but may be less visible when printed with high quality settings (smaller layer heights).

Here at Filament Forged, we use 0.2mm as the height for each layer. This is high quality enough to look good straight off of the printer, but still is fast enough to keep the prices low.


You can minimize the appearance of layer lines in two ways. Removing or Filling

  • Removing The most popular way to remove layer lines is with sanding. Using a sandpaper, you can buff away the lines until they are smooth. When doing this, it's encouraged to use restraint because 3D printed models are not solid. There is a hollow section inside, so if you sand too far, you make start to expose a hole. Our models are printed with two walls for extra security and structure so that you can sand with confidence. Just make sure not to overdo it. Sanding should always be done in a well ventilated area due to particles. You may also consider wet-sanding to avoid this.

  • Filling The next popular method is to fill the lines. This is particularly useful on very complex models that will be difficult to sand. A popular coating for this is called XTC-3D by smooth on #notsponsored. This is a glossy brush-on coating that will fill ridges. Using a spray can of filler primer is another good alternative. The filling will be less dramatic than a specially designed coating, but will still be a dramatic change from a raw model. Filling and sanding are not exclusive. You can use both techniques together to achieve amazing results.

  • Can you use Vapor Polishing? You may have seen acetone vapor polishing used on 3D prints, but this will not work with your purchased models. This type of polishing works through a chemical reaction that takes place with Acetone and ABS plastic. We believe that this type of process is very dangerous due to the use of strong chemicals both in the acetone and in the plastic. Because of this, we do not use ABS plastic for our models. Make sure that all post-processing tutorials you find online are designed for PLA plastic models.


Paint is the final touch for many models. Here at Filament Forged, we match the plastic color to the source material to keep any paintwork minimal. If you elect to do any post processing work, such as sanding, you may notice that the finish of your color has changed. To cover up any abrasions or variations due to post processing, painting is key. Below are some of my favorite paints, and the pros/cons to each: Acrylic paint

  • Pros - Cheap. Wide color variety. Colors can be mixed. Easily found at most stores. Easy to use

  • Cons - Brush strokes may be visible. Not as durable as other options (clear coat recommended)

Spray Paint

  • Pros - Smooth even finish. Certain varieties can be bonded with plastic for durable coating

  • Cons - Limited color selection. Messy application. Harder to access Must be over 18 to purchase from select stores.

Enamel Model Paints

  • Pros - High Quality. Customization with mixing and consistency. High Durability

  • Cons - Harder to use. More expensive. Additional materials required (thinners, cleaners, etc.)

There are a wide variety of options available, and the internet has a ton of resources available.

With that said, there is no right way to do post processing, just find the right one for you.

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