When 3D printers gained popularity, anyone who can get their hands on them got one and started doing creative projects. Although there is one issue with most models that use filament. Sometimes, the layer lines are pretty obvious, which can ruin the quality. There are ways that it can be resolved.
1. Sanding Them Down
This is the simplest and cheapest way to make the surface of your 3D print smooth. You can start off with 400 grit sandpaper to get rid of the most obvious bumps. Once you're done with that, work your way through sandpapers with higher grits.
For instance, you can go from 400 then 800, eventually using 3,000-grit sandpaper. One issue with this is that it can take a while before you have a completely smooth finish. Do make sure that you wear an appropriate mask to avoid inhaling small filament particles.
2. Using a Heat Gun
As you know, filaments are melted in order to create the shape you programmed your 3D printer to do, which means you can use a heat gun to mold it again after the machine does its job. You can use a heat gun at its lowest setting to do that, as suggested by All3DP.
Using the heat gun, the filament will melt a little bit, just enough for the surface to smoothen but not too much that it destroys the figure. Do try to apply heat on areas evenly for the best outcome. The filament can start melting at just 60 degrees, so it's also best to watch the temperature.
3. Epoxy Coating
If you want to make your 3D print appear glass-like, applying a coat of epoxy resin is your best method. You can use UV resin since they dry quicker under UV light or direct sunlight, but two-part resins also work, and they're cheaper.
You can use a paintbrush to apply the epoxy resin and make sure to apply it evenly. One of the best parts about this method is that you'll be preserving the color of the print since epoxy is clear. Your work will also look less plastic and more porcelain-like.
4. Using Solvents
Before you opt for this process, you need to determine which solvents work for certain filaments. For instance, acetone works on ABS, but won't affect PLA filament, as pointed out by Wevolver. No worries, there are other solvent variants you can use.
The solvent will melt the top layer which results in a smoother finish. The downside to this way of smoothing is that it can be dangerous since you're dealing with chemicals. Wear appropriate equipment like nitrile gloves, fume hoods, and eye protection.
5. Primer Coating
Coating using a primer is not really the best way to smoothen a 3D print. After applying a coat, you'll have to let it dry first, and you will have to sand it as well. If you're happy with the color of your filament, your best bet is with the previously mentioned techniques.
What's good about it is that primer is softer than the hardened filament, which means it will be much easier to sand after it covers up the visible layers. You'll also have an easier time painting the prints since primers are meant to be painted over.
