Sanding is one of the most widely used post-processing methods on PLA 3D prints, which helps remove any layer lines and imperfections. Sanding, however, doesn’t offer a very shiny result; it’s usually left rough and dull. In the case in which you’re pondering how to restore PLA after sanding, this guide is going to help you with several methods like polishing, priming, and finishing ways of getting a good look.

Why would PLA need Restoration after being Sanded?

Honestly, the most popular 3D printing material, PLA (Polylactic Acid), is very easy to work with and biodegradable. Although it can be sanded, it loses its sheen and appears cloudy or rough because, once sanded, it is hard to smooth the reflection of light on its surface and restore it to its original shine. This is necessary in the restoration of PLA after sanding as it would give a professional touch and increase durability.

Common Issues After Sanding PLA:

• Loss of shine or glossy appearance
• Visible scratches and uneven texture
• Color dullness
• Increase in surface hollowness leading to fingerprints.

Step-by-Step Guide to Restoring PLA After Sanding

1. Gradual Sanding for a Smoother Finish

Before polishing and restoration can be started, first and foremost do sanding properly.

• First, low-grit sandpaper (150-200 grit) will remove the layer lines.
• Next, use medium grit (400-600 grit) smoothing it down.
• Finish with high-grit sandpaper (800-1200 grit) for a nice smooth texture.
• Wet sanding at high grits is also very helpful in reducing scratching and heat build-up in the process.

2. Polish PLA to Restore the Glossy Finish

After that, the glossiness of the PLA can be restored by polishing it.

Ways to Polish PLA Include:

a) Using a Polishing Compound

• Apply plastic or automotive polishing compound to a microfiber cloth.
• Rub the surface in circular motions until the shine appears.
• Use a Dremel tool with a buffing pad for faster results.

b) Applying a Clear Coat Spray

• Use acrylic clear coat or polyurethane spray to add shine and protection.
• Apply thin, even layers, allowing each coat to dry before reapplying.

3. Priming and Painting for a Professional Look

If you prefer a painted finish, priming is essential.

Steps to Prime and Paint PLA:

1. Apply a thin layer of primer (automotive or filler primer) to the sanded PLA.
2. Let it dry and sand lightly with 800-1000 grit sandpaper.
3. Apply spray paint in thin, even coats.
4. Seal with a clear coat for added protection and shine.

4. Using Heat to Restore Shine

A gentle application of heat can bring back some of the lost luster.

Steps to Use Heat for PLA Restoration:

• Use a heat gun at low temperature (~200°F).
• Keep the heat moving to prevent melting.
• Observe as the surface regains its glossy finish.

5. Applying a Resin Coating

Epoxy resin can provide a smooth and durable finish.

How to Apply Epoxy Resin on PLA:

• Mix clear epoxy resin as per the instructions.
• Apply a thin coat using a brush.
• Let it cure for 24-48 hours.

Comparing Different Finishing Methods for PLA Restoration

Conclusion

Thus, restoring PLA after sanding involves proper sanding, polishing, and finishing methods. Whether one opts for polishing compounds, clear coats, or resin makes no difference for improving the final look. It is encouraged to experiment with different methods for finding one’s perfect finish on 3D prints!

FAQs : How to restore PLA after sanding