Welcome to our crash course on how to 3D print with PETG. PETG is one of the more popular materials that is used in 3D printing, mainly because it's relatively low cost. It is also almost as easy to print with as PLA but not quite. It has its own challenges attached to it that we are going to troubleshoot and share our solutions with you.
The first thing to know about PETG is, it is as mechanically durable as ABS and it is more thermally resistant than PLA. It will not melt inside of a hot car but it may possibly start to get soft a little bit inside of a super hot car in Arizona. You can make most cup holders and phone stands and that kind of thing out of PETG and have it be reliable. However if it's going to be in a super hot ambient temperature it doesn't always hold up perfectly.
One of the most common concerns that people have with PETG is that it has a lot of stringing inside of overhangs and moving from tower to tower. An overhang in 3D printing is when a piece of the design juts out over the side of the main part of the print. An example of this can be found with our Bubonic Plague Doctor design; the brim of his hat would be an overhang. A tower in 3D printing is when there is a small vertical part of the print that towers over a print. This can be seen in our Batman Headphone Stand with the two Batman ears. Maneuvering these types of prints can be hard when printing with PETG. Most of the time this is because either your PETG is wet or you don't have your retraction settings tuned just right.
Make sure that your temperature is high, between about 235° to 245° is optimal. Also make sure that your traction moves are quick around 90 millimeters per second minimum and make sure that your retraction is well equivalent to your printer, depending on what you're using (a bowden or a direct drive). Those are the main kinds of settings to help eliminate strain.
As far as bed materials, PETG works well with PEI sheets, and with glass beds. Make sure that your glass bed is very clean. A lot of people like to wash with alcohol, we recommend just underneath tap water. You can rub it with your hand until you feel the glass start to get a little bit tacky. That will create a good stick. You can even wash your bed in a dishwasher and that will work pretty well also.
To summarize, PETG is a good durable material with pretty good thermal resistance.
Just make sure that your cooling fan isn't turned on so the layers stick together well and make sure that your retraction moves are all tuned and quick so that you don't have much strain.