My full sanding and layer line filling process, plus the exact printer, filament, and finishing supplies behind it
3D printing changed everything about how I build props. What used to mean hours of sculpting or hunting down expensive pre-made kits is now something I can design or download, print overnight, and finish by hand. But the printer is honestly the easy part. The real difference between a prop that looks like a 3D print and one that looks screen accurate comes down to finishing, and that’s the part most guides skip.
Here’s my full setup, printer to final coat.
The Printer and Filament
Elegoo Neptune 4 Plus. This is the printer I use for basically everything, from small droid parts to larger armor pieces. It’s reliable, has a big enough build plate for most prop sizes, and doesn’t require constant babysitting mid print.
Shop the Elegoo on AmazonElegoo PLA+. My go to filament for most prints. It’s easy to work with, holds detail well, and sands down cleanly once you get to the finishing stage.
Shop Elegoo PLA+ Filament on AmazonRapid PETG. For pieces that need more durability or flexibility, like parts that’ll take some wear during a con or a charity appearance, PETG holds up better than standard PLA.
Shop Rapid PETG Filament on AmazonSanding Supplies
Every print comes off the bed with visible layer lines. Sanding is step one in turning that into something that looks intentional instead of 3D printed.
Dremel. For quick material removal on rough spots, seams, and support marks before the detailed sanding starts.
Shop Dremel Rotary Tools on AmazonSandpaper, assorted grits. I work through a full range from coarse to fine depending on the stage, more on that in the process breakdown below.
Shop Assorted Grit Sandpaper on AmazonSanding blocks. For flatter, more even pressure than sandpaper alone, especially useful on larger flat panels. Great for wet sanding.
Shop Sanding Blocks on AmazonPower Sander. For larger projects, a power sander helps ease the process. A mouse sander or orbital sander does the trick nicely, though I prefer a mouse.
Shop Mouse Sander on AmazonTrianglular sandpaper. You’ll need varying grits of paper for that mouse sander. Anywhere from 60 to 1000 and higher!
Shop Triangular Sandpaper on AmazonLayer Line Filling Supplies
This is the step that actually makes a 3D printed prop look screen accurate instead of like a 3D printed prop.
Filler primer. A spray primer built specifically to fill small imperfections, not just add color. This does a lot of the heavy lifting in the final smoothing stage.
Shop Filler Primer on AmazonUV resin and a UV light. My first line of defense against layer lines. Cures fast, sands smooth, and lets me work in small sections instead of waiting on air dry time.
Shop UV Resin on Amazon Shop UV Lights on AmazonAcrylic modeling paste. For filling slightly larger gaps or texture than resin alone can handle cleanly.
Shop Acrylic Modeling Paste on AmazonBondo spot and glazing putty. My go to for rough spots and deeper imperfections that need more aggressive filling before the final primer stage.
Shop Bondo Spot and Glazing Putty on AmazonMy Actual Process, Step by Step
Here’s exactly how I take a piece from freshly printed to finished, using everything above.
1. Print the piece. Straightforward, but this is where filament choice (PLA+ vs PETG) gets decided based on what the final piece needs to hold up to.
2. First sanding pass. Work through the grits in order: 60, then 120, then 200, then 400. I use a mix of sandpaper by hand and an orbital or mouse sander, and the goal at this stage is simple: remove as many visible layer lines and rough patches as you can before moving to filling.
3. First round of UV resin filling. Work in small sections, about 2 by 2 inches at a time. Apply the resin with a foam brush, then cure it with the UV light for 20 to 30 seconds before moving to the next section. Repeat across the whole piece. Direct sunlight can also cure UV resin in about 10 minutes, but be careful with this method on hot days, too much heat can warp or damage the print itself.
4. Sand again. Same grit progression as step 2, now knocking down the cured resin to blend it into the surface.
5. Spot fill remaining rough areas. Hit any spots that still need work with Bondo spot and glazing putty or acrylic modeling paste, whichever fits the size of the imperfection better. Let it fully dry before moving on.
6. Sand again.
7. Apply filler primer. 2 to 3 coats, letting each one dry fully.
8. Wet sand. Using wet sanding blocks, start at 120 grit and work all the way up to 1000 or higher for a truly smooth, paint ready finish.
9. Evaluate and repeat as needed. At this point, decide if the piece is ready or if it needs another pass through any of the steps above. Some pieces need every step repeated two or three times before they’re truly screen accurate. That’s normal, not a sign you did something wrong.
Bottom Line
The printer gets you a shape. The finishing process is what turns that shape into a prop that actually looks like it belongs in the movies. If you’re just starting out with 3D printed props, don’t rush the sanding and filling stages, that’s genuinely where the final quality comes from.
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