PETG UV Resistance: How long can you leave it in the sun?

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Every 3D printer needs at least some sort of raw material that it can use to safely and easily print the desired 3D build. Just as a conventional 3D printer uses ink and paper to create words and imagery, so too does the 3D printer need certain specialized raw materials to create different objects.

The overall quality and nature of these raw materials will ultimately determine the depth, size, quality, and scope of the object. In this regard, one of the best and most commonly available raw material or filament (as it is called in 3D printing terminology) is PETG or polyethylene terephthalate glycol.

One question often comes up: how is PETG UV resistance?

PETG is now used in many, if not most 3D printers around. As a matter of fact, it is now rapidly taking the place of both ABS and PLA as one of the top choices for all kinds of high tensile impact resistance and strength applications.

The different types of materials are often referred to as being “co-polyesters. This product strikes the perfect balance between very high strength and universal ease of use, and it is strong enough to be just like plastic.

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Is PETG UV Resistant?

In the long run, it is now a well-known fact that it will almost always come out on top when it comes to objects and builds that have to be resistant to ultraviolet (UV) radiation. I.e., UV resistant. This is why it is ideal for objects that have to be kept under the harsh mid-summer sun. This is because UV radiation has minimal effect on it as compared to PLA and ABS.

Where other filament materials (such as ABS, for instance) tend to weaken quite significantly when exposed to long bouts of sunlight, this one does not crack or become soft at all. In fact, if you need to build something for regular outdoor use, rest assured that it will last much longer than most 3D printing materials out there. This makes it a great material for car dashboard decoration pieces (for instance) and signboards that are constantly exposed to the elements.

What Happens If You Leave PETG Out In The Sun?

Since it is not prone to deformation, this filament will remain rock-solid in both wind and sun. As a matter of fact, despite the sun’s UV rays, any 3D printed part or component made from this material will not significantly change its shape, nor will its color fade either. This is because it is UV resistant as compared to other materials.

Which Is The Best Filament For Outdoor Use?

PETG (unlike ABS) has excellent stability, and it will not deteriorate in any number of harsh weather conditions. This is why this material has become the best 3D printing choice for all kinds of outdoor picnic food containers and commercial external signage.

It is also used in different medical equipment because it is built to last a long time. In the 3D printing world, any object that has been created with this material will almost always last for a very long time. You can hang a dream catcher made with this filament on your verandah, and it will remain there for years without ever losing any of its structural integrity, whatsoever.

Outdoor Applications for PETG

This filament 3D printing material has primarily been designed for outdoor use, and this is why it is extremely durable. That is, it will hold its own for a long time indeed. It is insensitive to changing temperatures and UV radiation to the extent that many experts consider it impervious to the external environment.

This makes it near perfect for use even in extreme conditions where it can be relied on, not to lose its shape or appearance, or become deformed in any way.

Since this filament has excellent layer adhesion, it can even be used in marine applications such as making small boat buoys and other marine components that have to bear exposure to the sun all day long. ASA also has similar properties too. In fact, both of these filaments are a good choice for all kinds of sports and outdoor work. Unlike PLA, that does not fulfill such criteria.

What Happens To PLA In The Sun?

There is a reason why PLA 3D printers filament is considered more of an indoor filament than its outdoor counterparts. This is because the sun will rot most PLA and ABS components.

Some filaments will take their time before they become brittle, but PLA will definitely be amongst one of the first to go. This means that even if some parts of your PLA 3D printed builds are exposed to the sun (car cabin decorations, for instance), they will become soft and fragile and easily broken.

This is a fairly common issue with most PLA and ABS filaments since they are not designed for such rigorous duty, and if forced into such service, they will succumb and break easily. However, external filaments such as ASA (for example) won’t do that at all.


What Happens To ABS In The Sun?

ABS 3D printing filament is not considered highly suitable for outdoor work due to its weakness in UV rays. It can survive in bitterly cold weather as long as it is not subjected to direct harsh sunlight when the UV factor is very high.
It tends to warp in a high-temperature environment while retaining its structural integrity in a very cold one. In fact, ABS (not to mention PLA) is notorious for falling apart wherever high mid-summer temperatures are concerned.


PETG is both stronger and more durable for any kind of external work that requires 3D print filament. Apart from that, it is also available in a variety of different shades and even transparent colors.

Its temperature resistance makes it a good choice for external applications. All I all, it would not be wrong to assert that it is one of the best filaments for 3D printing around, especially when used and compared to both PLA and ABS. If you want a UV resistant build, this is the one to get.

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In 2019 Shabbir bought a Tevo Tarantula and fell in love with 3D printing. He now shares his tips and love of 3d printing with the world exclusively through Maker Shop. Here's how he builds Ender 3s that can print at over 1000mm/s (25x stock!) for under $600.

4 thoughts on “PETG UV Resistance: How long can you leave it in the sun?”

  1. Hello,
    I’am in internship with Thales, I study the carbon footprint of different plastics, and I’m interested by your recycling technologies.
    Please, can I have the impact of the production of 1 kg of PET-G and recycled PET-G on the climate change.
    I need those informations to compare them with other virgin plastics.

    Thank you in advance
    Best regards

    Yassmina SABR

  2. How well does PETG hold up when used inside vehicles (i.e. for replacement trim, mini brackets, etc.) when the summertime temperatures reach or exceed 150*F?

    • Hey Chad,

      Short version is (depending on the filament brand/composition) it should hold up quite well!

      PETG’s glass transition temperature (the point where the plastic goes from “glassy” (hard) to soft-but-not-melted is typically between 80-85°C (176°F to 185°F).

      Your car can get to about 170°F (77°C) in the sun on a 100°F (37.78°C) day with the windows up.

      So, if you mean the interior of your car is at 150°F, you shouldn’t hit the glass transition temp and should be OK.

      But if you’re looking at a 150°F day in the shade: 1. where do you live (death valley?!), 2. it might be time to move, and 3. it wouldn’t work.

      I’ll assume you mean the car interior is 150°F, in which case PETG is great for this use case.


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