First long print (35 hours) PETG stringy and gaps in print

I’ll check out temp towers. I’m not familiar with OrcaSlicer, as this is my first printer.

Thanks for the input!

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Utilie les reglages par defaut de Bambu Studio. J’imprime beaucoup de PETG sans aucun problème.

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To all who replied and helped, thanks! I have never seen a forum ad helpful and responsive! I think i have a good course of action…

Temp was definitely low. I bumped it up to 255 and it all settled out, even when i shifted it to the “sport” mode and overran x by 126%. In the morning I’ll run a temp tower and figure out optimal temp.
I also think a more comprehensive drying process would be helpful. I just put it in the AMS for 3 days thinking that environment would dry it out.

@Viking27 Merci beau coup pour vos conseils

Again, thanks for the guidance!

That is true but unless the filament is significantly modified you wouldn’t see this much of a temperature difference.

Not necessarily. Remember that marketing can play a role in what gets printed on the spool too. A lot of printers can’t safely get up to 250 C, ones with PTFE lined hot ends, like the ender 3, so if you say you can print your PETG at 220 C then people with these printers, especially beginners, will be more likely to buy it.

As for no one getting good results with the filament that doesn’t always matter, especially for smaller or Chinese companies, which often compete on price rather than quality.

I know when I was getting started out I was fooled by the printing on the spool too with PETG, I had an ender 3 and bought PETG that said it could print fine at 220 C. While the results were better than this the part was very weak and the quality wasn’t great. Using the same filament after upgrading the ender 3 to an all metal hot end and printing it hotter got much better results, both in strength and quality.

Also an important thing to note is that bambu printers use stainless or hardened steel nozzles. On other printers when changing from brass to hardened steel you need to increase the temperature by 10-20 C to compensate for the lower thermal conductivity, so that could be playing a role here too.

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You are picking a difficult model for your first long print. This is supposed to print multiple plates stacked on top of each other but able to be separated afterwards. I believe they do this by leaving a vertical gap between the plates. It looks like your print may be failing when it goes to print the next plate on top.

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Yeah, you’re not kidding on the difficult part comment. Every assumption you made is correct. I posted final results below.

To wrap up this story… here’s the final results. First panel printed pretty nicely (for my level of experience). The second layer, starting with the panel “gaps”, as mentioned above, was a mess. Those problems continued intermittently until i upped the temp.
Panels separated nicely and still seemed strong. Need to refine things more and understand my materials and process before doing a print that size again.

I think a temp tower and drying process are next agenda items.

Wait a moment… Are you printing those on top of each other???


Ok, this is starting to make more sense now. If this print is being nested on top of each other, the problem may be more about slicing and modeling.

Definitely do the temp tower in Orca Slicer (not sure in Bambu Slicer has the temp tower option). That should show you the best temp to print at to get rid of the stringing.

And if you must nest them on top of each other you’ll need to model that in the CAD software. Honestly, that sounds like it will be too difficult to do for someone with very little experience 3D printing, so I’d suggest just doing one at a time.

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I recently bought a large bundle of PETG specifically from FIROS and also was very surprised by how low their temperature was labeled on ALL 12 SPOOLS of different colors I got from them. I too mistrusted the label as most of the previous comments suggested and tried printing at a more ‘normal’ PETG temperature, but surprisingly with my Bambu Lab A1 I found the best nozzle temperature was about 230C across all the colors, which would follow their 220 recommendation +10 and accounting for the steel nozzle vs brass. It printed alright at 220, though the color was more matte at that temperature despite still having strong layer adhesion. The Generic PETG profile in Bambu Studio was too hot and ended up stringing and blobbing with holes in the outer walls of my parts. Thought it would be valuable to share my own similar experience with this specific brand of filament.

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The model comes already stacked, with a 0.2mm gap, quick allows them to be separated easily. You are to iron the top surfaces and they turn out fairly well on that suitable. They’re designed to be mounted just off the surface of the wall, so one pretty side is fine.

Good info… here’s my temp tower ranging from 250 to 280… Best quality of the options is 250, but it got worse moving away from 250. I’m going to adjust the scale to go from 220 to 260 and see what shows up

That’s exactly it… kinda a challenging one

I’m seeing a lot of comments about the temp is too low. I’ve been printing PETG for YEARS at 230, just fine. Higher temp can help some things, but I’ve printed a half dozen brands with many colors at 230.

As for the stringing, expect some, but you can minimize by keeping travel within the model.

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The problem with nesting them on top of another is PETG can have bridging difficulties if the filament isn’t well tuned, setting-wise. So, the issues you are having now make a lot of sense to me.

Good luck getting this sorted out, but I’m still going to say you are likely best to do one at a time as well get that 220-250C temp tower done and use the best level.

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Banding in this case is a result of printing a stack of prints with a 0.2mm air gap in between. this print is actually four plates put on top of each other, look at “multi board” on thangs, you’ll see the single boards and the stacks.
So when it fails it does on the.2mm gap between the parts. This is not a material problem.
low temp and adhesion play a role in this as well, sure but this is also a tricky print due to basically printing things on top of things that need to adhere but not really stick to each other, much like part and support structure.


I understand this configuration and stacked printing is a challenge, the print definitely got better as the tempos came up. While stacked printing is neat and novel, i also am coming to the conclusion that the juice might not be worth the squeeze. Long print times seem potentially volatile and it’s pretty easy to pull the part and hit “print again”. Perhaps I’ll change my mind down the road, but at this point, it just adds unnecessary stress.