The strength, flexibility, and versatility of PETG plastic make it a popular material for 3D printing projects in workshops around the world. For many newbies, however, one question crops up once they’ve printed their models – is PETG dishwasher-safe?
Spoiler alert – the answer is that it’s safe in terms of toxicity, but it’s not necessarily a good idea.
PETG is generally safe to clean in your dishwasher, but there are a few things you should keep in mind if you want to make sure your projects last for many years to come. On this page, we’ll explore this robust printing material and tell you everything you need to know when building projects with it.
What does PETG Stand for and What Does it Mean?
PETG stands for Polyethylene Terephthalate Glycol. This might sound prohibitively complicated, but all you really need to know is that it’s a relatively flexible, strong, versatile, plastic that’s great for most projects.
It’s very similar to the type of plastic used for most commercial plastic water bottles, only with an added glycol. This addition provides extra strength to the resulting material which is well suited for 3D printing.
PETG combines the heat resistance, strength, and durability of ABS with the consistent results of PLA filament. So, what’s the catch? The good news is that there aren’t many downsides to working with PETG. You just need to keep a few things in mind when cleaning it.
Okay, But is PETG Dishwasher Safe?
Let’s do some quick maths. PETG has a glass transition temperature (the temperature at which things start to melt) of 80-85 degrees Celsius. Most home dishwashers operate between 50-60 degrees Celsius.
In short, this means that most dishwashers will be perfectly safe for your PETG projects. Once properly cured, PETG isn’t toxic or harmful within these temperatures. However, this doesn’t mean that all dishwashers, dry cycles, and cleaning settings will be 3D project friendly.
Check out some of our general guidelines below.
PETG and Your Dishwasher – Things to Keep in Mind
Just because PETG is safe and non-toxic in most dishwashers doesn’t mean there aren’t a few things to be wary of. You also need to make sure that the structural integrity of your builds isn’t compromised by an overzealous cleaning.
You can quickly ruin a whole day’s work with a single cleaning if you’re not careful! For this reason, it’s worth considering other cleaning methods for your smaller builds.
Read on to get clued up on the basics.
Watch Your Temperature Setting
Some home dishwashers can get as high as 75 degrees Celsius. Double-check your unit’s temperature setting before trusting it with your projects. Once temperatures get this high, your projects can easily start to warp.
Even 65-70 degrees Celsius could be risky for thinner parts of your builds. It’s always worth checking first to avoid disappointment later on. If in doubt, carefully hand-wash instead.
The Crystallization Process
Explaining the crystallization process of PET materials is beyond the scope of this article (dive into this paper if you’ve got the academic chops). However, the long and short of it is that exposure to higher temperatures can sometimes cause chips and cracks along the surfaces of your builds.
This will depend on the shape, size, and intricacy of each specific project. If in doubt, avoid using your dishwasher, especially if it runs on the hotter side.
Keep an Eye on Your Dry Cycle
The drying cycle of your dishwasher is designed to evaporate the water left on your dishes and cutlery. This means that it tends to run significantly hotter than the rest of its cycle. Unless you’re confident that the temperature inside won’t surpass 65 degrees Celsius, it’s best to remove your PETG prints before the dry cycle starts.
Could This Just as Easily be Hand Washed?
We get it – the dishwasher is a super convenient way to clean things without really having to think about it. With your 3D prints, though, it’s worth thinking about simply washing the project yourself.
With smaller prints, you can usually be finished within a minute or so and you won’t have to worry about damaging your projects or dishes! Use your best judgement when making a decision.
Related: Is PETG food-safe?
What to do if your PETG Items Warp
So what if you’ve already messed up some of your projects? Don’t worry, help is at hand. Try some of our tips below.
Toxicity
Generally speaking, the hotter a PET material is, the more toxic it becomes. This means that in most home dishwashers, you shouldn’t have much to worry about. Your build will likely just warp without leaching much of anything onto the rest of your appliance.
If your machine runs abnormally hot (90+ degrees Celsius), however, you might have to replace your trays, cutlery, and dishes with any melted plastic on them. Don’t worry though – this is very unlikely to happen with most dishwashers.
How to Recycle PETG Projects
While this may be of little solace when you’ve lost a huge printing project, it’s worth remembering that PETG can be recycled, at least in some cases. Check with your local council or recycling centre before dropping it off to be repurposed.
PETG is structurally very similar to PETE plastics. This means that at some facilities, PETG is actually rejected for recycling as it can interfere with their separation processes. In short, check your specific area to be sure.
The Bottom Line – is it Safe?
In most cases, PETG is safe to clean in your dishwasher at home. The most important thing to get your head around is temperatures. If your dishwasher cleans at temperatures below 65 degrees Celsius, you shouldn’t have anything to worry about.
If your dry cycle or general cleaning cycle operate close to or above 65 degrees – it’s probably best to hand wash instead.
In fact for most prints, you probably don’t really need to use a dishwasher anyway. Sometimes a little elbow grease works best!
