Is PETG Easier To Sand Than PLA?

Polyethylene terephthalate glycol-modified (PETG) is one of the top filaments in 3D printing since it’s relatively easy to work with but is even more durable than PLA. However, while PETG makes a more substantial substitute for PLA when it comes to post-processing, that durability translates into some challenges. 

PETG is not easier to sand than PLA. PETG is more durable than PLA, so it takes more effort to sand it. However, PETG is less porous than PLA, so you do not have to remove much material to get a shiny, smooth surface with PETG. 

In this article, I’ll compare the sanding process for PLA and PETG. I’ll also provide tips and tricks for sanding PETG and PLA 3D prints so you can get the best results with the least effort possible. 

Sanding PLA vs. PETG: Which is Easier?

Although sanding is a pain, getting a smooth surface for 3D printing is often necessary, especially if you plan to paint your objects. However, sanding is usually everyone’s least favorite part of 3D printing since it takes time and effort. 

So, if you want to save some work, choosing a material that is easy to smooth and sand is a great idea. However, there’s no clear winner regarding the ease of sanding PETG and PLA. Each one is easier to sand in some respects than the other.

Sanding PLA

PLA is one of the softest, most porous filaments available, so if you want to sand down layer lines, it won’t take too much time or arm strength. 

With coarse grit sandpaper, the layer lines should “pill” or roll off in little chunks after a few swipes. 

However, PLA is difficult to sand evenly. You may have to sand away more material to get a slightly shiny, layer-less finish on your prints. That’s because PLA usually has a porous, matte finish, even if you use a silky filament. 

So, when sanding PLA, you can expect layer lines and artifacts to come off your print with minimal sanding. But if you want a smooth, shiny, and seamless finish on a PLA object, you will have to remove more material. 

Sanding PETG

PETG, on the other hand, is a solid and durable plastic. It has a slightly translucent finish — which can be a huge pain when sanding. 

PETG is tougher to sand, and it’ll take some intense scraping to get layer lines and artifacts off it. While that fact might make it seem like PETG is all-around harder to sand than PLA, PETG still has a few tricks up its sleeve. 

Since PETG is harder and less porous than PLA, it offers more resistance as you sand it. That means you won’t have to grind away much material before your 3D-printed object has a smooth, seamless finish. 

Overall, PETG takes more effort to sand than PLA, but you won’t have to remove as much material as you would with a PLA print. 

Another factor to consider is that PETG has a slightly translucent surface. When you sand PETG prints, you usually damage that silky shine, resulting in a dull, lusterless object.

Properties of PETG Compared to PLA

When considering whether PETG is easier to sand than PLA, it’s essential to understand each material’s strengths and weaknesses. After all, each filament is best for specific applications. 

Here are some of the characteristics of these filaments that impact how easy it is to post-process them:

Properties	PETG	PLA
Tensile Strength at Yield	50 MPa	51 MPa
Elastic Modulus	2.1 GPa	2.3 GPa
Density	1.27 g/cm3	1.24 g/cm3
Glass Transition Temperature	85 °C (185 °F)	55 to 60 °C (131 to 140 °F)
Melting Point	180 °C (356 °F)	165 °C (329 °F)

As you can see in this table, PETG is more rigid, less elastic, and denser than PLA. That means it may be harder to chip away PETG plastics than PLA.

However, it also means that when you put pressure on PETG while sanding, it will bend less than PLA. In some cases, that property makes it a lot easier to sand PETG than PLA. 

In addition, with the increased density of PETG, the surface won’t be naturally rough and porous, which makes for less sanding before you achieve a glossy surface. 

Tips For Sanding PLA and PETG

Sanding a 3D print of any material requires the same basic steps regardless of the filament used, with the only real variation coming from the length of time needed to get a smooth finish. In addition, there are some tricks to sanding both PLA and PETG. 

Wet Sand Your 3D Prints

When sanding both PLA and PETG, the plastic may clog up your sandpaper. To prevent this clogging, it’s best to use a spray bottle of water to wet your print or your sandpaper as you work. 

The water will collect the plastic dust and keep it from getting stuck deep into the grit of your sandpaper. Plus, that dust collection means fewer plastic particles in the air you breathe, so wet sanding is a great way to stay safe. 

Avoid Using a Machine Sander on PLA

Hand and machine sanding are the most common methods for sanding a 3D print. 

Machine sanding with a drill or a Dremel is best for larger prints made from durable materials like PETG. If you attempt to sand PLA 3D prints with a machine, you might accidentally take too much material off. It’s a lot easier to do than it sounds. 

So, if you have a PLA print to process, I recommend using plain sandpaper in at least three grits. 

This method is relatively simple and does not require any special equipment. All you need is a sheet of sandpaper and a few hours.

Conclusion

PETG is a versatile 3D printing filament used for various applications. It is known for being solid and durable, but is it easier to sand than PLA? 

Well, it depends. PETG is easier to sand in terms of how much material you must remove. PETG is dense and strong, so you do not have to remove much material before you get a seamless finish. On the other hand, PLA takes less strength to sand, but you’ll have to remove more material to eliminate bumps and lines from it.