Use ASA for anything in the sun, PETG for parts below deck or out of direct light, and TPU for seals, bumpers and grips. Avoid PLA on a boat.
What a boat does to plastic
- UV light breaks down many plastics, leaving them chalky and brittle.
- Heat on a dark deck or dash in summer can soften low-temperature plastics.
- Salt water and moisture are constant, though most printing plastics don't absorb much water.
- Vibration and impact crack brittle parts at thin corners.
ASA: the first choice above deck
ASA was developed as a weather-resistant cousin of ABS. It keeps its strength and color in sunlight and handles heat up to roughly 95 to 100 °C. We use it for instrument bezels, hatch latches, trim pieces, rod holder parts and cleat covers.
PETG: below deck and in lockers
PETG is tough, shrugs off water and many chemicals, and costs a little less. It will slowly yellow and weaken in direct sun, so keep it for cabin, locker and engine-room-adjacent parts that stay out of the light and away from high heat.
TPU: seals, bumpers and grips
Flexible TPU makes good gaskets, hatch bumpers, fender-style pads and non-slip feet. It stays flexible in cold weather.
Skip PLA
PLA softens around 55 to 60 °C and degrades in sun. It is fine for a fit check, but not for a part that stays on the boat.
Hardware tips
- Use stainless screws, and add heat-set brass inserts where a part gets unscrewed often.
- Ask for thicker walls and more infill on parts that take loads.
- Lighter colors stay cooler in the sun than black.
- Anything structural or safety critical, like steering or through-hull fittings below the waterline, should stay metal or certified OEM.
Older boats, discontinued parts
A lot of boats around Kitsap and Puget Sound are old enough that the builder stopped making parts. Send us the broken piece or photos with measurements and we will model a new one. See replacement parts and how to measure a broken part.
Local to Kitsap? Bring it to our Olalla shop. Call (360) 621-1881 first. Elsewhere in the US, we ship.