Choosing the Best Finishing Method for Your 3D Prints

Avoid visible layer lines and achieve a perfect finish for your 3D prints with these top techniques.

Today's FDM 3D printers achieve excellent surface finishes despite the fact that they produce items using layers. But why settle for a good surface finish when you can have a perfect surface finish? Join us as we explore the best 3D printing surface finishing techniques available to you, from simple sanding to acetone vapor baths.

Sanding your 3D prints is the simplest way to create beautiful surface finishes. This doesn't mean that the process is fast, and you need to be patient to get the best results with this method. You have two choices: hand sanding or power sanding. Each option comes with its own benefits, so let's take a look at them both to get you started.

Sanding 3D prints leaves them with a smooth finish. You can polish your sanded prints to give them a shiny finish or leave them unpolished for a matte effect.

While it may be time-consuming, hand sanding is an effective way to finish your 3D prints and make them look great. Sandpaper can be found in hardware stores, online, and even in your old toolbox, but you need to have sandpaper in various grits to get the best results. Sanding blocks can also be used for this.

Rubbing the sandpaper or sanding block in circular motions is a good way to avoid scratches or an uneven finish. Apply little pressure when sanding 3D printed plastics; the sandpaper should do all the work for you.

Using a power tool to sand your 3D prints is fast and effective, and you can choose from a range of tools to do the job. Belt sanders, orbital sanders, and detail sanders are the most common power sanders available on the market. Any type of power sander will work, although detail sanders are generally considered the best for 3D print finishing.

Much like hand sanding, you should start with medium grit sandpaper and slowly work your way towards ultra-fine grits when using a power sander. You must take extra care to avoid heat build-up as you work, as power sanders move faster than your hands and generate more friction.

Power sanders are fast, affordable, and easy to use, as long as you have the right safety equipment (gloves and goggles). Precision work will be impossible with tools like this, making hand sanding a better choice for small parts.

Polishing your sanded 3D prints will help you to achieve a mirror finish. You don't need to buy anything special for this to work; products like Brasso make short work of plastics. Just apply some of your polish to a soft cotton cloth, buffing your 3D print with it until it looks nice and shiny. Buffing in circles is the best way to maintain a smooth finish.

Chemical smoothing for 3D prints takes out all the manual work that comes with sanding. A chemical is used to break down the outer layers of the 3D printed object, smoothing it out and reducing the appearance of layer lines. This type of process is fast and effective, but it can also risk damaging your 3D prints if you make mistakes along the way.

For chemical smoothing to work, you need to find a chemical that reacts to the filament material you have used. PLA, ABS, and PETG all have different chemical properties, and this means that different chemical agents and methods are used to smooth them. You can learn about the different types of 3D printable materials in our guide to choosing filament types.

Like many plastics, ABS can be dissolved in acetone. By exposing a 3D print made from ABS to acetone vapor, you can smooth its surface in minutes and with very little work. Of course, though, acetone is extremely flammable and toxic, and great care is required when working with it.

You can buy premade acetone vapor chambers that are designed to work well for 3D print smoothing. Alternatively, you can also build your own acetone vapor chamber using a glass or metal container.

Unlike ABS, PLA doesn't dissolve well in acetone, but it can dissolve in ethyl acetate. Ethyl acetate is the main ingredient in nail polish remover, and it has the same flammable qualities as acetone. Using nail polish remover is a good choice for this as it isn't highly concentrated and is safe for use on the skin.

You can apply ethyl acetate nail polish directly to the surface of your print or use a vapor chamber to apply it. It's important to make sure that you thoroughly clean your 3D print after going through this process to avoid a prolonged chemical reaction.

Its strong chemical resistance is one of PETG's most popular features. This makes it difficult to find a chemical that can dissolve PETG and provide a smooth finish, but dichloromethane can do the job. Unfortunately, dichloromethane is very dangerous and should only ever be handled by professionals. For this reason, sanding is usually the best finishing method for PETG.

Unlike sanding or using chemical smoothing, epoxy resin adds material to your 3D print to make it smooth. Epoxy is a two-part liquid solution that begins to solidify once the two components are mixed together. It can either be clear or colored, and the fact that it starts as a liquid before becoming a solid makes it ideal for finishing 3D prints. This is not the same type of resin used for SLA 3D printing.

Mix your solution together before applying a thin layer to the outside of your 3D print. You can use a paintbrush for this, making it easier to get into the tightest parts of your print. Some epoxy resins require curing to solidify properly, so it is important to read the instructions that came with your resin to get the best results.

Choosing the correct slicer settings and using high-quality materials are good ways to improve your 3D prints. Sometimes, though, it makes sense to take extra steps to ensure that your 3D prints have the best possible finish. The ideas in this article will help to get you started, but you can learn more about 3D printing finishes to take your own models to the next level.

Samuel is a UK-based technology writer with a passion for all things DIY. Having started businesses in the fields of web development and 3D printing, along with working as a writer for many years, Samuel offers a unique insight into the world of technology. Focusing mainly on DIY tech projects, he loves nothing more than sharing fun and exciting ideas that you can try at home. Outside of work, Samuel can usually be found cycling, playing PC video games, or desperately attempting to communicate with his pet crab.