Messy and Stringy Supports

Hello, I am working on a Lulzbot TAZ Pro. I have started to have issues when printing objects that require supports. It seems like the printer is having a hard time printing the supports accurately, and the prints end up very messy and stringy, with lots of little pieces falling off during the print. Here are a couple of pictures:

Here are the details of what I am using for this print:

Hatchbox PETG filament
Cura Lulzbot 3.6.37

Material: PETG (IC3D)
Profile: High Detail
Print Setup: Recommended
Infill: 20%
Generate Supports: Yes
Build Plate Adhesion: Skirt

I wonder if some of my problem stems from selecting a material (IC3D) that isn’t exactly the filament I am using? On the roll of Hatchbox PETG filament it says “Extrusion Temp: 240 - 260 C” but the PETG IC3D material settings have the hotend at 230 C. This hasn’t been a problem for prints that don’t require supports, or that require minimal supports, but with something that requires quite a lot of supports (the pencil cup you see in the picture) something is definitely going wrong.

If anyone could point me in the right direction of even what to try to narrow down what’s causing this, I’d be grateful!



I use the PETG IC3D profile when printing replacement parts in PETG with the M175v2 my Taz 6, and haven’t had any issues with supports. Settings look the same:

PETG is known for stringiness, but what you have there looks excessive. I use MatterHackers Pro PETG in mine.

Is your filament too damp?

Also, this design looks like it was not designed with FDM printing in mind, which is amplifying the negatives of PETG.

Thank you for your reply!

You’re absolutely right. I am teaching a 3D printing class for kids using Tinkercad as the design software, and although we talk about designing with FDM limitations in mind, often the designs don’t end up being really feasible to print. I think it’s a good experience for them to see failed prints like this and we can talk about what went wrong.

But in this case, I’m thinking there must be more going wrong, or a variable that is not quite right to cause messiness of this magnitude?

Good question! How can I tell? How can I control wetness, would that be printing temperature?

The easiest way to tell is to listen and watch as the filament exits the nozzle. If you see steam or hear a popping noise then the filament has absorbed some water. Storing the filament in an air-tight container with some desiccant is how you prevent it from absorbing water but this will not dry it out. For that you need a heated environment. See this article for details (this applies to PETG as well).

Thank you, that is very helpful! I haven’t seen any steam and/or heard popping and I live in the Southwest US where the air is very dry, so I’m thinking that probably wetness of filament isn’t a factor in my case.

Filament dryer is a great investment.

PETG pulls in moisture with ease, so don’t expect to hear the sizzle and pops. It’ll mostly show up as excess stringiness. I dry before use and use a PolyBox filament dry box which has lots of desiccant to keep the moisture level low.

Also, an enclosure and fume extractor is also a great idea. PETG outputs some nasty VOCs and Nanoparticles. Print safe.

Thanks for the info. We are mostly going to stick to PLA in the future, I think. But I should try the filament dryer for sure, and I appreciate the heads up on the fumes.

Interestingly, I only get the stringiness when I am printing something with supports. If I’m printing something that doesn’t require supports, it prints with the PETG perfectly.

I work at a University and get asked by schools why we do what we do in regards to safety. This is a good read.

Fantastic. I’m at a Public Library, and we want to make sure we are conscious of safety was well.