PETG Chemical Resistance: Alcohol, Acetone, Bleach and Oil
PETG resists water, oil, grease, gasoline, antifreeze, diluted bleach and dilute acids, takes an alcohol wipe but gets more brittle in a long alcohol soak, and is attacked by acetone, paint and lacquer thinners, toluene and strong alkalis like ammonia. That makes it a clear step up from PLA, which loses strength in alcohol and collapses in acetone.
Below is the test data behind that answer, what it means for a printed part, and what a PETG part costs. Mandarin 3D prints PETG made to order in black or white: 20% more on the print and 3 to 5 extra business days.
PETG vs PLA, chemical by chemical
Prusa soaked test pieces of its PLA and PETG filaments for a week at 23 °C and rated how much they swelled or changed weight: A is under 1%, B is 2-3%, C is 4-5%, and D is over 5% or destroyed. From Prusa's chemical resistance table:
| Chemical | PETG | PLA |
|---|---|---|
| Water | A | A |
| Isopropyl alcohol 99% | B | C |
| Ethanol | B | C |
| Vinegar (8% acetic acid) | A | B |
| Bleach cleaner diluted 1:10 | A | B |
| Antifreeze (ethylene glycol coolant) | A | B |
| Hydrochloric acid 37% | A | C |
| Sulfuric acid 96% | D | D |
| Acetone | C | D |
PETG beats or ties PLA on every line, and the only household liquid where it rates poorly is acetone.
What a week in each liquid does to its strength
A part can weigh the same and still turn brittle, so weight change is only half of it. A 2025 study in Polymers soaked printed PETG test bars for 7 days at room temperature, then pulled and struck them:
| After 7 days in | Tensile strength kept | Impact strength kept |
|---|---|---|
| Water, 8% vinegar or 30% hydrogen peroxide | over 97% | 92-97% |
| Ethanol 99.5% | about 94% | about 90% |
| Isopropyl alcohol 99% | about 85% | about 64% |
| Hydrochloric acid 37% | about 80% | about 72% |
| Acetone | about 30% (50% after one day) | a similar drop |
In the same study PLA lost more than half its impact strength after 7 days in every alcohol and more than 70% of its tensile strength in acetone.
Prusa's own strength tests found the same pattern. PETG's tensile strength moved by only a few percent in most liquids, but its toughness dropped in isopropyl alcohol, vinegar, acetone and coolant. In diluted bleach it held steady for 24 hours and slipped to about 92% after a week.
A year in household and garage liquids
Eastman, which makes PETG resin, kept molded 3.2 mm bars of its Eastar 6763 copolyester in liquids for a full year at 23 °C. Its rule of thumb: don't keep a plastic immersed in anything that changes its weight or thickness by 5% or more.
| Liquid | Weight change after 1 year | How it looked |
|---|---|---|
| Motor oil, automotive grease, transmission fluid | under 1% | No change |
| Antifreeze | under 1% | No change |
| Regular gasoline | under 1% | Slight yellowing |
| Bleach (3.5% sodium hypochlorite) | under 1% | Slight yellowing |
| Hydrogen peroxide 3% | under 1% | Slight yellowing |
| Sodium hydroxide 1% / 10% | under 1% / 8% | Slight yellowing |
| Ammonia solution 10% | 4% | Pink, blistered surface |
| Lacquer thinner | 7% | Cloudy, white |
| Gasoline with 10% ethanol | 9% | Cloudy |
| Acetone | 16% | Brown, swollen, rubbery |
| Toluene | 26% | White, softened |
One line not in the table: methanol barely changed the weight but left fine cracks, called crazing. Weight alone doesn't tell you a part is safe.
Why a printed part does worse than the chart
These numbers come from solid bars. A printed part differs in three ways:
- Layers and infill let liquid in. Gaps between lines give a liquid more surface to work on, and a part at 20% infill is mostly air behind thin walls. If a part will sit in a liquid, design it with thicker walls, 2-3 mm rather than 1.2 mm.
- Load speeds up the attack. A clip, snap fit or screwed-down bracket under stress can crack in a liquid that leaves a loose part alone. That is what the methanol crazing shows.
- Heat speeds up the attack. Prusa notes that chemical damage rises steeply with temperature, so room-temperature data says little about hot water or a warm engine bay. PETG itself starts to soften at about 68 °C.
Chemical resistance is also not food safety. A plastic that survives vinegar is not certified for food contact, and we don't print food-contact parts.
So, for common jobs
- Garage and workshop parts near oil, grease or coolant: a good fit for PETG.
- Holders and caddies for spray cleaners and diluted bleach: fine. Rinse off spills of full-strength products.
- Parts you wipe with alcohol or disinfectant wipes: fine. Don't leave them soaking in 99% alcohol.
- Anything in a fuel system or sitting in fuel: no. Gasoline with ethanol clouded and swelled Eastman's bars.
- Anything near acetone, nail polish remover, paint thinner or strong ammonia cleaners: no.
- Drain cleaner, oven cleaner and other strong acids or alkalis: no. Bambu Lab's datasheet for the PETG Basic we print lists it as not resistant to acids or alkalis, and resistant to most oils and greases.
If PETG isn't enough, polypropylene and nylon both resist acetone in Prusa's table. We don't price them instantly, but you can ask about other materials in the AI designer chat. For heat, strength and price side by side, see PLA vs PETG.
What a PETG part costs
Live quotes from our quote API on November 11, 2026, for parts from our catalog, one piece, shipped by USPS Ground Advantage anywhere in the US, before tax:
| Part | PLA | PETG |
|---|---|---|
| Pegboard hook | $9.26 | $10.03 |
| Wall hook | $9.70 | $10.66 |
| Shelf bracket | $10.47 | $11.46 |
| Drawer organizer bin | $11.43 | $12.74 |
| Box with a snap-on lid | $12.46 | $13.89 |
PETG adds 77 cents to $1.43 on these, because the 20% applies to the print only, not the order fee or postage. Open any of them and pick PETG next to the colors.
Get it printed
Drop your STL, 3MF or STEP file in the box below and switch to PETG on the quote to see the price before you pay. The quote shows the ship date.
Questions
Is PETG chemical resistant?
To most everyday liquids. Water, oil, grease, gasoline, antifreeze, diluted bleach and dilute acids barely change it. Acetone, paint and lacquer thinners, toluene and strong alkalis such as ammonia attack it.
Is PETG resistant to isopropyl alcohol?
For wiping, yes. Soaked for a week in 99% isopropyl alcohol, printed PETG kept about 85% of its tensile strength but only about 64% of its impact strength, so don't store it in alcohol.
Does acetone dissolve PETG?
It swells and softens it rather than melting it away. In one study printed PETG kept about half its tensile strength after a day in acetone and about 30% after a week. Keep PETG away from acetone and nail polish remover.
Is PETG more chemical resistant than PLA?
Yes. In Prusa's week-long soak tests PETG rated better than PLA for alcohol, vinegar, diluted bleach, antifreeze and hydrochloric acid, and a PLA test bar collapsed in acetone.
Is PETG resistant to bleach?
Diluted household bleach, yes. A year in 3.5% bleach changed Eastman's PETG copolyester by less than 1% in weight, with slight yellowing.