How hot, how wet, how long?

What temperature can a printed part actually take?

PETG holds its shape to roughly 80°C in continuous use. Below that it is stable. Above it the part does not melt, it slowly creeps out of shape under its own load.

Creep is the thing to understand, because it is not how people imagine plastic failing. Nothing dramatic happens at 85°C. The bracket just sags a millimetre a week until the thing it was holding is no longer where it should be, and you notice in a month.

That matters for how you judge the risk. A part that gets briefly warm is fine. A part that sits warm all summer under load is not, even at the same temperature.

Will it survive on a car dashboard?

Marginally. A dark dashboard in direct British summer sun passes 80°C, which is the edge of what PETG tolerates. Out of direct sun, a car interior is comfortably within range.

So the answer depends on where in the car. A trim clip inside a door card, a bracket under the seat, a cable guide behind the console — all well within range and all things we print regularly. A phone mount lying flat on the dash of a black car in July is asking a lot.

In an engine bay, no. Underbonnet temperatures and oil exposure are far past PETG, and a failure there is not a cosmetic problem. More detail on the automotive printing page, including what we will not take on.

Can a printed part go in the dishwasher?

Bottom rack, usually fine. Top rack on a hot cycle with heated drying can reach the temperature where PETG softens, and thin parts can distort. Hand washing is the safe answer.

Dishwasher basket wheels and rack clips are a different case — they are down in the bottom, they are small and solid, and they take it well. We print those often. A thin printed utensil holder in the top rack is the thing to be careful with.

Detergent itself is not a problem. PETG resists it well, better than PLA, which breaks down over repeated cycles.

What about outdoors in British weather?

Rain, frost, damp and cold are no trouble. PETG does not absorb water or go brittle in winter. The slow enemy is ultraviolet light, which reduces toughness over several years.

Practically, a PETG part on a shed, a fence, a garden tool or a bike will do years of service. It will gradually become less able to take a sharp knock, long before it looks any different.

We allow for that by printing outdoor parts thicker than the strict minimum. If you tell us a part is going outside, that changes what we do with it.

Is it safe for food?

The raw material is food contact approved and is the same family of plastic as drinks bottles. The complication is the printed surface, which has fine grooves that trap residue and resist cleaning.

Our position is that printed parts are fine for dry contact or brief contact — a scoop, a jar clip, a shelf support — and that we would not recommend one for anything stored wet for long periods. It is a hygiene point about the surface, not a toxicity point about the plastic.

How long will it last compared to the original?

Often longer. Most parts that reach us broke because the original moulding had gone brittle with age, and PETG is tougher than the material many of them were moulded in.

The exceptions are parts that were originally nylon or glass-filled for a reason, and parts that were originally transparent. We cannot match either. If the original was clear, we will tell you before you order rather than after.

When will you tell me no?

When the part holds a person up, holds pressure, sits near an engine, or belongs to a braking, steering or restraint system. No thickness or material swap changes those answers.

We also say no when the honest answer is metal, or a nine pound universal fitting from a motor factor. It costs us the order. It is still the right thing to say, and it is the reason the rest of this page is worth believing.

Published 5 October 2026.