PETG for Outdoor Use: Everything You Need to Know

When 3D printed parts need to survive outdoors, material choice becomes critical. Rain, sun, temperature swings, and UV radiation are harsh on plastics. Many common printing materials fail within months outside.

PETG stands out as an excellent choice for outdoor applications. Here’s why we use it for most of our outdoor products.

What is PETG?

PETG (Polyethylene Terephthalate Glycol) is a modified version of PET, the same plastic used for water bottles. The glycol modification makes it easier to print while maintaining excellent material properties.

Key characteristics:

• Temperature resistant up to 70-80°C
• Excellent chemical resistance
• Good UV stability
• Impact resistant
• Food safe (in its pure form)
• Easy to print with proper settings

PETG vs other materials outdoors

PETG vs PLA

PLA is the most popular printing material but fails outdoors:

• UV degradation: PLA becomes brittle within months under UV exposure
• Temperature sensitivity: Softens around 60°C - easily reached in direct sunlight
• Moisture absorption: Takes on water, weakening the structure
• Biodegradable: Great for the environment, bad for longevity

PETG solves all these problems. It’s stable under UV, handles higher temperatures, and doesn’t absorb moisture significantly.

PETG vs ABS

ABS is a traditional choice for functional parts but has drawbacks:

• Harder to print: Requires enclosure and proper ventilation
• UV sensitive: Yellows and becomes brittle in sunlight without coating
• Emits fumes: Printing produces potentially harmful gases

PETG is easier to print and naturally more UV stable than ABS.

PETG vs ASA

ASA is specifically designed for outdoor use and is the best choice when UV resistance is paramount. However:

• More expensive than PETG
• Harder to print (similar to ABS)
• Less available in colors and variants

For most applications, PETG provides 90% of ASA’s performance at lower cost and easier printing.

Real-world performance

At 3Dennis, we’ve been printing outdoor parts in PETG for years. Here’s what we’ve observed:

Year one

Prints look essentially new. No visible degradation, no loss of strength, colors remain vibrant.

Years two and three

Slight surface changes may appear on the very top surfaces (facing direct sun). Structural integrity remains excellent. Dark colors hold up better than light ones.

Long-term

With proper design (drainage, avoiding trapped water), PETG parts last many years outdoors. We have parts in service for 5+ years with no functional degradation.

Tips for outdoor PETG prints

Design considerations

Include drainage: Don’t create pockets where water can pool. It freezes in winter and can crack even resistant materials.

Avoid thin sections: UV degradation happens from the outside in. Thicker walls mean the core stays protected.

Use dark colors: Black and dark gray resist UV better than white or light colors. The pigments act as UV blockers.

Design for thermal expansion: Plastic expands in heat. If parts are constrained, include flexibility in the design.

Print settings

Higher infill: For outdoor use, we recommend 30-40% infill minimum. It adds strength and thermal mass.

More perimeters: Extra wall lines protect the infill from UV exposure. We typically use 4 walls for outdoor parts.

Lower layer height: Smaller layers mean better layer adhesion and a more solid structure. 0.2mm is our standard.

Proper temperature: Print PETG at the right temperature (typically 230-250°C) for maximum layer bonding.

Common outdoor applications

Mounting hardware

Our most popular outdoor products are mounts for:

• Security cameras
• WiFi access points
• Weather sensors
• Outdoor lighting

PETG provides the strength and weatherproofing these applications need.

Garden and patio

Plant pot holders, irrigation system components, outdoor cable management - all work great in PETG.

Automotive accessories

Phone holders, dash mounts, and similar accessories survive the heat and UV inside cars (though ventilated interior is better than direct sun exposure).

Marine applications

PETG’s chemical resistance makes it suitable for mild marine environments. Constant saltwater spray is challenging for any plastic, but occasional exposure is fine.

When PETG isn’t enough

There are situations where PETG isn’t the best choice:

Extreme UV exposure: Parts facing direct equatorial sun 8+ hours daily may need ASA or UV coating.

High temperatures: Black parts in direct sun can exceed 80°C. If the part is structural, consider alternatives.

Chemical exposure: While PETG is resistant to many chemicals, some solvents will attack it. Check compatibility for your specific use case.

High precision requirements: PETG shrinks slightly and can warp. For very tight tolerances, post-machining may be needed.

Our recommendation

For 95% of outdoor applications, PETG is the right choice. It offers the best balance of:

• Durability
• Printability
• Cost
• Availability

At 3Dennis, PETG is our default material for outdoor products. We’ve proven it works through years of real-world use.

Need outdoor parts? Browse our products or contact us for custom solutions.