Creating clean armor and props for a costume is easy with a 3D printer. The surface prep though can make the task sometimes difficult. This guide will answer “how do you smooth 3D prints on cosplays” to make them clean and free of layer lines.
The key techniques for smoothing 3D printed filaments involves your printer settings, sanding, filler primers, spot-filling and wet sanding. You’ll often need to do a combination of these 5 things.
How to Get Rid of 3D Print Lines
To minimize 3D print lines we’ll need to adjust the print settings. Consider changing settings such as:
- Lowering your slicer’s layer height between 0.08mm and 0.16mm
- Slowing down your outer wall speeds to 40-60 mm/s
- Enable adaptive or variable layers to automatically decrease layer thickness only on steep curves or angled details but still save time on vertical or flat walls
How to Sand 3D Prints for Cosplay
There is a few stages of sanding and spot-filling to do for your 3D prints.
- Step 1. Sand the raw print – With a lower grit sand paper (80-150), do an initial pass of sanding on your raw, assembled print. Always sand with the direction of the layer lines to shave off peaks.
- Note: Be careful not to press too hard or the friction can melt the plastic.
- Step 2. Sand again – I typically will sand my prints again with a 320 grit sandpaper.
- Step 3. Spot-fill gaps – Use a spot-filler such as Bondo spot putty, wood filler or an Acetone-slurry (ABS scraps with Acetone) to fill in large gaps and seams.
- Step 4. Sand the spot-filler – Sand down the spot-filler with a 220-320 grit.
- Step 5. Prime the print – Clean off dust from sanding down the spot-filler. Then apply a layer of filler primer all over the print. You can also touch-up spots with your spot-filler again after the filler primer dries.
- Step 6. Final dry sanding – Sand down the spot-filler and filler primer one more time with a 400-600 grit sand paper.
- Step 7. Wet sand the print – This is when you want to use your finest sandpaper, such as 600-1000 grit. You will wet sand your print to get a glossy, smooth finish.
What Grits Should I Use to Sand 3D Prints
I use a few different grit sand papers throughout my surface prep process:
- Initial sanding of raw print – 80 – 150 grit
- Second sanding before fillers – 320 grit
- Third sanding after fillers – 320 grit
- Fourth sanding after primers – 400 – 600 grit
- Wet sanding – 1000 grit
What is the Best Sanding Tool for 3D Prints
While you can just use regular sheets of sandpaper or sanding sponges, there is helpful powered tools that can help speed up the process.
- Reciprocating sanders –
- Pros: Great for fine details and tight corners
- Cons: Take longer for large surfaces
- Top Brands: NeoSander
- Hand Detail Sander –
- Rotary Tools –
- Pros: Great for rapid material removal and comfortable to hold during long-period use
- Cons: High speeds can cause too much friction and melt prints
- Top Brands: Dremel, Ryobi
How to Polish 3D print After Sanding
The best way to polish 3D prints is by wet sanding with a very fine grit sandpaper such as 1000. You can also for translucent filaments seal them with epoxy resin to make it perfectly smooth and clear.
How to Smooth PLA Without Sanding
While sanding may be inevitable for smoothing out 3D prints, you can also try chemical solvents to melt that outer layer or apply filler primer. However you will often still need to sand with filler primers. Epoxy resin sealing could also be used for smoothing out your prints.
What Chemical Can Smooth Out PLA?
While acetone can work for ABS, it doesn’t dissolve PLA as easily. To chemically smooth PLA you need ethyl acetate or other specialized PLA-smoothing agents. You can use this for vapor smoothing inside a sealed container or even a brush-on method.
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