How to Post Process PLA 3D Prints

Once your 3D prints are finished printing, you can take more steps to make things look better. This is called post-processing which a lot of people might not know how to do properly. I decided to write an article on how to post process PLA 3D models so they have a cleaner finish.

Keep on reading for more information about post-processing PLA models.

Here’s how to post process PLA 3D prints:

Remove supports
Clean any stringing
Sand the model
Glue & assemble if needed
Priming & painting

Remove Supports

After you remove your 3D model from the print bed, you may have some supports that need to be removed. Some models can be 3D printed without supports, but a lot of models will require them.

Removing supports is usually a pretty simple process and you can sometimes just remove them by hand. In other cases, you might need to take some flush cutters, pliers, or a X-acto knife, then remove them carefully.

I find that using a combination of tools is the best method because supports come in different shapes and crevices, so one tool might not be able to reach certain places.

You can purchase yourself a Rustark 34-Piece 3D Printer Toolkit that has several cleaning, carving tools that will help you remove supports much easier.

I wrote an article about How to Remove 3D Print Supports Like a Pro which you can check out.

You can also use settings in your slicer to make supports easier to remove such as lowering your printing temperature, using a support pattern like Zigzag or Lines, decreasing Support Interface Density in Cura, and increase Support Z Distance.

The video below takes you through how to remove supports from 3D prints.

Clean Any Stringing

Some models might have other imperfections like stringing, which are thin strands of filament between two points on your model. These can be cleared up by applying a heat source to the model like a hair dryer or a heat gun.

When applying heat with a heat gun, be careful not to use it too close to the model, even at its lowest setting. This is because the heat gun can deform your model, especially if it is a PLA model.

Check out my article 5 Ways How to Fix Stringing & Oozing in Your 3D Prints for more details.

Many users who have tried to use heat guns have stated how efficient it is in removing stringing. One user stated that he uses a small heat gun to remove stringing on his prints. They are relatively cheap to purchase.

You can get something like the SEEKONE Heat Gun from Amazon. It has a temperature range of 50-650°C and has features like overload protection and variable temperature control.

A user who bought this heat gun said it works wonderfully and gets rid of any stringing with ease. You can use it just for a second or two and the stringing should be fixed. Some people have even used a lighter, but you’ll have to be more careful with it.

Here’s a short video to demonstrate this process.

Sand the Model

Once your model is clear of supports and other imperfections, you can do some sanding to make layer lines invisible and make the model much smoother. You can use different grits of sandpaper, starting low to take off more material, then moving up to higher grits to smooth things over.

It’s a good idea to use some safety equipment such as a facemask and safety glasses to reduce exposure to the dust from sanding. Some people even choose to do wet sanding so you don’t get the dust floating around.

A lot of the time, you might get support marks on your model. Sanding can clear these up pretty well.

I’d recommend going with the PAXCOO 42Pcs Sandpaper Assortment 120-3,000 Grit from Amazon. Users who bought this for 3D printing said it worked really well for sanding their models, and that they especially like the extremely fine grit sandpaper.

They had no issues with dry or wet sanding using these. You do have to be gentle at first when sanding though, so you don’t take off too much material. Starting with a grit like 100 can work well, then you gradually work your way up to around 300 grit and above to your desire.

When you 3D print models with a higher resolution (smaller layer height) sanding becomes easier. Users recommend to sand perpendicular to layer lines, which is basically the opposite of parallel to the layer lines. If the layer lines are _ direction, then you sand | direction.

Doing wet sanding is better in many cases because it helps to prevent discoloration when sanding, and works great for the finer grits of sandpaper. PLA can even start to melt from dry sanding if you sand quite hard.

I wrote an article called 8 Ways How to 3D Print Without Getting Layer Lines which you might find useful.

Glue & Assemble if Needed

At this point, you can glue and assemble your model if you have multiple pieces that are coming together. You’ll want to sand the pieces again where they join to make the seams smooth. This is useful when you are creating models that are larger than your 3D printer’s build plate.

For PLA models, using superglue is usually the best method. You can also use things like Bondo or epoxy resin. Epoxy can be better suited for bonding models with large surface areas, while superglue is better for smaller surface areas.

If it’s possible, use some small clamps to hold the pieces together until it dries.

Some users have even welded their PLA models together using a soldering iron, by using the heat to melt the PLA and stick it together so it hardens as one piece.

For any gaps in your model, you can use some Bondo Spot Putty to fill them in before doing any painting work. I wrote an article called Best Filler for PLA & ABS 3D Print Gaps & How To Fill Seams.

Priming & Painting

Once you’ve done your sanding and any necessary assembly, here’s where you do so some final priming and painting. Priming is a process of applying a product to your model that helps the actual paint stick to the model.

You can choose from several colors of spray paints, even with some unique metallic finishes. This is the best way to get a nice smooth and shiny finish to your models. There are even final clear coats that you can apply to give some extra shine to your model.

The first step is to use a primer on your model which serves as a base before you paint the model. Primer also helps to reveal any holes and gaps that may be present on the model’s surface. Some primers are also fillers, so they can fill gaps in your models.

A great product that’s really popular for this is the Rust-Oleum Automotive 2-in-1 Filler & Sandable Primer from Amazon. One user who sells 3D prints said this is a game changer for them.

Another user said it is excellent for 3D print finishing, just grab some sandpaper and get excellent results. They also mentioned that it coats models evenly and dries quickly.

After applying primer, as mentioned in the name, you can sand it to smooth over the surface. Users recommend to apply multiple coats of primer, up to around 3 coats, while letting each layer properly dry and sanding between them. Thin coats are better for getting the best results.

Check out the video below for post-processing 3D prints by sanding, filling, then priming.

He made a follow-up video to finishing the model with painting. He paints the Deadpool helmet with metallic colors, with the base being a beautiful gold color to complement the red spray paint and give a metallic-looking finish.

He even does a really useful base coat paint test on spoons to see how different the paints looks.