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How to get smooth surface with FDM 3D Printing?

How to get smooth surface with FDM 3D Printing?

Among all 3D printing technologies, FDM considered the most affordable 3D printing. Depends on the printers and the print thickness, the finishing of the printed model may not be as smooth as SLS, SLA or MJP.

Not to worry, in this tutorial, we are sharing with you the tips and tricks to improve the surface finishing for PLA FDM printed model.

Items we need:


1. Hardware Tools for removing the supports


2. Sandpaper for smoothen the surface (different grade of sandpapers)


3. Wood Wax Filler for filling up the gaps or holes


4. Spray Filler to improve the top coat before spraying


5. Spray Paint for final finishing colour



6. Spray Varnish to protect the sprayed surface


Let’s get started…


1. Removing your 3D Print model from 3D Printer

2. Removal of support (depend on case-to-case basis – no support for this part)

We need to remove the support parts, using the flush cutters to cut the supports attached to the parts.

3. Smooth Surface Part using Sandpaper

You may notice the model with uneven surfaces due to the printing steps. To smoothen the surface, we can use the sandpaper (minimum 120 – 150 grits) and sanding away the uneven surfaces. You may use some water to make the sanding easier and smoother.

4. Apply Wood Filler

After sanding, you will notice there are some gaps or holes in between the surfaces due to the printing thickness. We can apply wood filler to the surfaces. If you have the water-based filler, you can add some water to the mixture for easy application. After applying the wood filler, leave it to dry fully which may takes approx. 5 hours or 7 hours depending on the brand you purchased. You can check the instructions from your bottle.

5. Smoothen Surface Part using Higher Grits Sandpaper

Once when wood filler is fully dry then we can use sandpaper 320–600 grits to make smooth the surface part. To make it a better smoothing.

6. Apply spray filler

Before spraying the finishing colour, we can apply spray filler as base for smoother and even colour.

7. Spray paint

Depend on the colour of the spray, you may need to apply approx. 3 layer of spray paint. In between each later, you need to wait at least 10mins so that the paint does not merge or causing uneven finishing or inconsistent thickness look.


We hope this simple tutorial helps you.

Credits to Men’s Hobby for the video – You can view his video instruction here.

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