Quick pick: use PLA for prototypes and indoor parts, PETG for tough functional parts, TPU when the part needs to bend or seal, and ASA for anything that lives outdoors, on a boat or in a car.
The four plastics side by side
| PLA | PETG | TPU | ASA | |
|---|---|---|---|---|
| Stiffness | High | Medium | Flexible | Medium-high |
| Toughness | Brittle when it fails | Good | Excellent | Good |
| Heat (approx. softening) | 55 to 60 °C | 75 to 80 °C | Varies | 95 to 100 °C |
| Sun and UV | Poor | Fair | Fair | Very good |
| Water and chemicals | Fair | Good | Good | Good |
| Relative price | Lowest | Low | Medium | Medium |
PLA: the default for looks and fit checks
PLA prints crisp detail and comes in the most colors. It is stiff, so it is great for checking size and fit. Its weakness is heat. A PLA part left on a car dashboard in summer can sag. Use it indoors.
PETG: the workhorse for functional parts
PETG bends a little before it breaks, which makes it more forgiving than PLA for clips, brackets, knobs and housings. It handles water and many household chemicals well. If you are not sure what a functional part needs, PETG is a safe start.
TPU: when the part needs to give
TPU is a rubber-like plastic. We use it for gaskets, bumpers, feet, grips, phone cases, and hose barbs that seal by stretching over the hose. It prints slower than rigid plastics, so it costs a bit more per part.
ASA: built for outside
ASA holds its color and strength in sunlight and handles heat far better than PLA or PETG. It is our choice for boat hardware, exterior fixtures and car interior parts. If your part has to survive a Pacific Northwest summer on a deck, pick ASA.
Common parts and what we would use
- Prototype housing for a fit check: PLA
- Replacement appliance knob: PETG
- Cable clip or shelf bracket: PETG
- Chair glide or bumper: TPU
- Hatch latch or bezel on a boat: ASA
- Dashboard phone mount: ASA
When plastic is the wrong answer
Parts that carry heavy loads, run near engines or heaters, or are safety critical should stay metal. We will tell you before you pay if we don't think a printed part will hold up.
Compare all materials on our materials page, or upload a file to see prices in each plastic.