PETG Filament 101

What is PETG filament?

PETG stands for “polyethylene terephthalate glycol-modified”. This means it’s a transparent copolyester. It’s retains its transparency and integrity even when exposed to a myriad of chemicals or stresses.

PETG has quickly gained popularity in the 3D printing world for its versatility, quality and reasonable price.

The only difference between PET and PETG is that it has been glycol-modified. This has made the plastic filament stronger, clearer and much less brittle. Opening up a wider range of uses for it.

Where can you see PETG in everyday life?

PET is actually one of the most common plastics around, PETG is similar, but has been glycol modified. Whilst PETG is often used for more specialist uses like creating braces for people’s teeth, PET can be found in many everyday items: water bottles, clothes and food storage containers.

Once printed how long does it last?

Once printed PETG, like many plastics, essentially can last forever. It takes an incredibly long time to break down naturally. This filament has been specifically designed to resist alkaline and acidic chemicals from degrading it, making it long-lasting and resilient. It could last for hundreds of years. I’ll get into why that’s not always so great ahead.

Is PETG environmentally friendly?

NO. Not at all. PETG, well PET mostly as it’s the more common of the two, is awful for the environment. The ocean is littered with huge quantities of this plastic and micro plastics, entire ecosystems have been decimated by these plastics. Fish choke on them, whales eat them by accident and die as a result.

This absolutely isn’t the plastics fault, the plastics didn’t put themselves in the ocean. Of course, it’s people we should blame for this, however, if the plastic wasn’t made so resistant on purpose and was allowed to biodegrade we wouldn’t have this problem. Just something to keep in mind.

Is PETG toxic?

As I mentioned above, PETG is used in braces, in water bottles and food storage. This filament as absolutely non-toxic so long as you don’t ingest it. Being used as food packing is one of the most prolific uses for this form of plastic. So no, it’s not toxic.

When the filament is being printed you should still avoid inhaling the fumes, as they can still be potentially harmful. Once the filament has been printed however it’s completely safe.

What are the pros of using PETG filament:

There are plenty of reasons why PETG is so common, it’s got lots of upsides for varying different projects you could have.

Its strength:

It’s very strong, unlike some other filaments. It’s incredibly durable and is used in manufacturing for its great impact resistance. If you’re looking for a filament that’s going to come under a lot of pressure when printed, this could be the one for you.

Its versatility:

PETG has a wide application of uses, its unique transparency opens up plenty of doors for its use. It’s strong enough to be used for mechanical purposes, but could also be used for creating art and toys.

Its ability to be sterilized:

Unlike other filaments, such as ABS, PETG is able to be sterilized and used for applications where this is relevant, such as for use with food. PETG doesn’t run the risk of making you sick and doesn’t give off carcinogenic chemicals, if it comes in contact with your food.

It’s able to be recycled and reused:

It may not be easy to recycle and reuse this filament, but it is possible. Recycling this filament means you make less of a negative imprint with any waste, and could save you money potentially. You shouldn’t try to recycle PETG yourself unless you know exactly what you’re doing.

What are the cons of using PETG filament?

PETG may be great but it does have some negatives that need to be explained, to help you get all the information you need about whether this is the right filament choice for you.

It hates sunlight:

Just like vampires and many other forms of filament, PETG doesn’t like the sun. UV rays are capable of damaging, distorting and warping PETG prints and potentially making them useless. If you were planning on printing something that was going to be used outside, maybe don’t. Unless it’s art and you want to see how it’ll look after the suns messed your print around a bit. Because it will certainly mess your print around.

It can be easily scratched:

PETG can be easily scratched, even more so than its brother PET. This is something to bear in mind when using. Just because scratching is possible doesn’t mean it will scratch, or even that if does it’ll be a problem.

When picking your filament this may be important to you and is something you might want to consider.

It can be difficult to print with:

Not all filaments are easy to use, and PETG is no exception. It can be very temperamental and may require a lot of trial and error adjusting specific settings that you print with, before you start to see consistent positive results. Don’t be disheartened if it takes a little while for you to start get the hang on this tricky filament.

How to print with PETG?

If you’re reading this article I’m sure you know how to use a 3D printer already, but as I mentioned above PETG can be a bit temperamental. It’s probably going to take you some experimentation with some trial and error before you find the best setting for your printer + filament combo. But this should hopefully give you a good launching off point.

Printing temperature probably wants to be about 235 degrees Celsius. It can be as low as 220c or as high as 250c. It’s best to start in this middle of that range and adjust as necessary.

Unlike some other printing beds, that like to be quite high, this filament does better when the bed is around 60 degrees Celsius. No less than 50c, no more than 75c is the rule of thumb here.

When trying to find the best print settings for you. It’s best to start at a slow speed of about 15mm/s. Once you’ve found the right settings, the speed can be increased. No more than 40mm/s is a good guideline to stick to.

How to store PETG filament:

Like all filaments, PETG needs to be kept in a sealed storage container to stop it from becoming damaged. The biggest risk is that the filament will draw in water moisture from out of the air and become unusable.

It’s best to keep all your filaments stored together in a box, perhaps printing the box could be your first task for this filament?

Where can I buy this filament from?

PETG filament has become common enough that you should be able to find it on Amazon, or whichever 3D printing store you may visit in person or online.

As a last resort If you are unable to find the specific colored spool of filament that you were hoping for, you could always order from the manufacturer directly. It can sometimes work out cheaper this way, but not always.

How much does PETG filament cost?

This filament will cost you slightly more than it’s counter part PLA, and much more than ABS. It could end up being as little as $20 a spool, or as much as $50. A lot depends on color, quality and which manufacturers you end up choosing from.

Is it completely food safe?

Most PETG filaments are indeed food safe, as mentioned above. However, it’s best to check the packaging first. If you’re unsure, check with the manufacturer. Don’t ever use any prints for food related purposes if you aren’t 100% sure that it’s safe. The risk is not anywhere close to worth the reward.

Is PETG the right filament for you?

Only you know what the best choice is, it depends so much on your budget and what your print will be. Here are some comparisons to other common alternatives to help you see how they match up and decide if PETG is the correct filament choice for you.

PETG vs PET:

PETG is much better than its counterpart, it is a lot stronger and is capable of resisting sudden stresses much more reliably. It’s can be a little more pricey but it’s worth it if you plan to be making a mechanical part.

PETG v PLA:

PLA is similar to PETG in a lot of ways, it’s much less likely to scratch and offers more variation in color and material blend. It isn’t as strong however, as PETG will stand up to much high stresses and is more temperature resistant. They are both food safe. PLA is, however, much easier to use.

PETG v ABS:

PETG Is much less toxic than ABS, where PETG is great for use with food ABS should never be used this way. ABS is however, much more durable than PETG, ABS will bend under stresses that would cause PETG to break.

Conclusion:

I hope this article has helped you decide if PETG is the filament type for you. If you’re looking to be using it with food, it surely is. If you’re looking for something stronger, maybe ABS is the way to go. If you’re looking for something easier to use, it maybe PLA who wins the day.

It’s best to pick your filament based on the project you have in mind, they all have their own advantages and disadvantages. Only you know what’s best. View other filaments types here.

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