Why I Swapped Outdoor Prints From PETG to ASA

PETG used to be my default answer for outdoor 3D printed parts. It printed easily, held up better than PLA, and did not require the babysitting that tougher materials often demand.

Then I started making parts that had to live outside for real.

Grill parts. Handles. Pieces that sit in direct sun. Parts that may spend time in Georgia heat, near a grill island, or inside a closed truck. That is where PETG started to feel like a compromise instead of a solution.

For those jobs, I moved to ASA.

Outdoor parts need to survive heat, sun, and real use.

PETG was good until the heat showed up

PETG is popular for a reason. It is stronger and more heat resistant than PLA, and it is much easier to print than ASA or ABS. For brackets, organizers, indoor utility parts, and general shop pieces, PETG still makes sense.

I used it for outdoor parts because it felt like the safe middle ground. PLA can deform in a hot car or under direct sun. PETG gives you more headroom and better toughness.

The problem is that “better than PLA” is not the same as “best for outdoors.”

PETG starts to soften around 75 to 80 C, or about 167 to 176 F. That sounds hot, but it is not hard to reach in the real world. A dark part in the sun can get hotter than the air around it. A closed truck in summer gets brutal. A grill island can trap heat. A part near a cooker sees repeated heat cycles.

That gap matters.

ASA is closer to 100 C, or about 212°F, before it starts to soften. That extra margin is the reason I changed the materials for anything that sits outside or sees heat.

ASA handles sun better than PETG

Heat was only part of the decision. Sun exposure was the other big one.

PETG can work outdoors, but over time it can yellow, fade, and get brittle. UV exposure is rough on plastics. If a part is tucked under cover or only sees occasional sun, PETG may last a while. If it sits out all season, the weaknesses show up faster.

ASA was made with outdoor use in mind. It has better UV resistance than PETG, so it holds color and strength longer when exposed to sunlight.

That is why I use ASA for the Big Green Egg replacement handles I sell. A grill handle is not a desk trinket. It gets touched, pulled, heated, cooled, rained on, and baked in the sun. I want that part printed from a material that fits the job.

The enclosed printer is the catch

ASA is not a drop-in upgrade for every printer.

The biggest catch is that ASA wants a hot, stable chamber. It shrinks as it cools. If one part of the print cools faster than another, the part can warp, lift from the bed, or split between layers.

That is why open-frame printers struggle with it. A drafty garage makes it worse. Even a small temperature swing can cause corners to curl or layers to separate.

I print ASA on a Bambu P2S, which is enclosed. That enclosure helps retain heat around the print and keeps the chamber more stable. For ASA, that matters as much as the nozzle temperature.

If your printer is open-frame, I would not start with ASA unless you add an enclosure first. PETG is usually the better choice for that setup. It is easier, more forgiving, and less likely to waste half a spool on curled corners.

My starting ASA settings

Every printer and filament brand is a little different, but these are the ranges I expect for ASA:

Setting	Typical range
Nozzle temperature	240 to 260 C
Bed temperature	90 to 110 C
Part cooling	Low or off
Printer setup	Enclosed chamber preferred

I usually keep part cooling low or off because too much cooling makes warping worse. ASA does not like being chilled mid-print.

Bed adhesion also deserves attention. A clean build plate matters. So does enough first-layer squish. ASA can look fine for the first few layers, then slowly start lifting as internal stress builds.

That is one reason I do not treat ASA like PETG. PETG is forgiving. ASA asks you to control the environment.

A stable chamber helps ASA prints stay flat and strong.

The downsides are real

I like ASA for outdoor parts, but I do not pretend it is perfect.

The first downside is the smell. ASA gives off styrene when printing. You need ventilation. An enclosure helps hold heat, but it does not replace fresh air or a proper filter setup.

I do not treat an enclosed printer as a magic safety box. It keeps the chamber warm. It does not make fumes disappear.

ASA is also fussier than PETG. A cold chamber can ruin a print. Bed adhesion takes more work. Stringing can be worse, depending on the filament and settings. Large parts need more care than small ones.

And if the printer is sitting in an open, drafty garage, ASA is probably the wrong call. You can fight the material, but at some point it makes more sense to choose the material that matches the machine.

Where I still use PETG

Indoor parts

Parts out of direct sun

Quick shop fixtures

Open-frame printer jobs

Where I use ASA

Outdoor parts

Grill parts

Parts exposed to heat

Parts that need better UV resistance

PETG still has a place in my shop

Switching to ASA did not make PETG useless.

I still use PETG for indoor parts. I still use it when I want something easy and durable. If a part stays out of the sun, does not see high heat, and does not need long-term UV resistance, PETG is still a good material.

That is the point. The best filament is not always the toughest one. It is the one that fits the job.

For indoor utility parts, PETG wins on convenience. For outdoor, grill, or heat-exposed parts, ASA is the better match.

Finished parts should be matched to the environment in which they will live.

The simple rule I use now

If the part lives indoors, PETG is usually fine.

If the part lives outside, sits in the sun, rides around in summer heat, or goes near a grill, I print it in ASA.

That is why my replacement handle kit is printed for outdoor use and sold with the hardware included. You can find it here: Big Green Egg replacement handle kit.

You can also visit the shop at Shaw3D on Etsy, or watch the shop work on YouTube.

Shop-made replacement. Not affiliated with Big Green Egg.