A 60 °C cockpit kills PLA in weeks
PLA: polylactic acid, is the default 3D printer filament. It's cheap, it prints easily, it looks good off the bed, it smells faintly sweet. It is also plant-based plastic that warps above 55 °C and disintegrates under UV.
A black part on a teak deck at noon in July gets to 60–65 °C without much effort. We measured it with an IR thermometer on a Bavaria 40 in a Slovenian marina on a 32 °C ambient day. The plastic doesn't melt at that temperature, it does something subtler and worse: it slowly creeps. The threads in your cradle slowly back out. The cradle loses its tension. By the time you notice, you have an iPhone bouncing on the deck.
UV is the second killer. PLA loses about 15% of its tensile strength per 200 hours of direct sunlight. A full sailing season in the Adriatic is 600–800 hours of sun. By August the cradle that held your camera at the start of season cracks the first time someone pulls firmly.
ASA was developed for outdoor signage
Acrylonitrile Styrene Acrylate (ASA) is the polymer your garden chairs are made of. It exists specifically because the original ABS (think Lego bricks) yellows and embrittles in UV. ASA was developed for outdoor signs that need to look the same after 10 years on a highway.
For our purposes it has three properties that matter:
- Glass transition temperature of 105 °C. It doesn't creep at deck temperatures. A 60 °C cockpit is 45 °C inside ASA's working envelope.
- UV-stable for >5 years of direct sun exposure with negligible strength loss.
- Salt-spray inert. It doesn't absorb water, doesn't swell, doesn't grow surface deposits that bind to dirt.
The price difference at print stock is about €10 per kilogram. Per part, that's an extra €0.40. We pay it on every single SKU.
The 90-day test
In summer 2026 we mounted three identical phone holders in the same Slovenian marina slip on the same Bavaria 40:
- Generic Etsy PLA, black: €18 listing
- AdriaFab PETG-CF prototype, internal, not for sale
- AdriaFab ASA production part, currently shipping
Two months later (sustained 28–34 °C ambient, an estimated 480 hours of sun):
| Part | Visual | Mechanical |
|---|---|---|
| Etsy PLA | Surface chalking, faded from black to dark grey | Cradle no longer clamps the phone. Bolt thread inserts spin freely. |
| PETG-CF | No visible change | Holds spec |
| ASA | No visible change | Holds spec |
The Etsy PLA wasn't a counterfeit or a knock-off. It was a respected American maker selling premium-looking parts on Etsy. The product simply wasn't engineered for the marine environment.
What this means for buying anything 3D-printed for a boat
Ask the seller two questions:
- What's the material? Refuse anything that just says "plastic." Look for ASA, PETG-CF, ASA-CF or nylon. Avoid PLA, PLA+ and any "premium PLA" claim: that's marketing, not chemistry.
- What's the hardware? A4 / 316 stainless or marine-grade aluminium only. Zinc-plated steel rusts inside three weeks of salt spray.
If those answers are unclear or hedged, the part will fail by August. We've seen it on every boat in the marina that buys cheap.
