Been playing with PETg filament.

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(Electra Flarefire) #1

Been playing with PETg filament. And after getting it working and printing a rather nice coffee cup, I found my prints are not very waterproof using this stuff.
So I created some test pieces and got it working. It now holds water just fine.
EDIT: The ‘bad bridging’ is intentional to expose any leaking into the infill. See the desc in the link below for full details.

I suspect the problem has deeper roots than just fixing it with extrusion width(I suspect filament diameter and extruder calibrations of both being out a tiny amount.). But this also solves and will let me test the other problems later.

PETg is lots of fun, prints well, is very strong. The only downside is that it seems 40-50mm/s is about the fastest I can print without problems. And it’s a bit pricey compared to PLA/ABS.

(Adam Steinmark) #2

What brand PETG? eSUN has some on Amazon Prime for ~$29

(Electra Flarefire) #3

@Adam_Steinmark https://www.bilby3d.com.au/Filament.asp#PETG But I’m quite sure it’s rebranded and it dosen’t look like eSUN’s spools.
Even PLA/ABS is expensive here. Cheapest is about $25-30 a kg and you never know what your getting.

(Duplicat 3D) #4

I’ve read about using wax, to make vases water-tight, but that doesn’t seem like it would be safe or desirable for drinking cups.
Is acetone vapor or XTC smoothing an option for PETG?

(Adam Steinmark) #5

@Electra_Flarefire Have you tried Hatchbox from Amazon? That’s my go-to brand.

(Electra Flarefire) #6

@Adam_Steinmark I don’t think amazon is in Oz at all and I refuse to use it. But even with online places, ebay, etc. postage becomes the problem very quickly. $15 or $20 spools quickly become 25/30 once postage is applied for a 1kg+ package.
@Duplicat_3D (Why did google mark you as spam?) Dichloromethane and a few other even more nasty chemicals are involved. But I doubt I’ll need it, just seems to be tuning the printer right and then you get a very solid, very strong printed model. The latest test cup hasn’t lost a drop after 2 hours.

(Ray Kholodovsky) #7

I’ve printed the twisted gear vase in spiral vase mode with only 2-3 floors out of normal esun pla and it was waterproof. Is your leaking out the bottom? I think the bridging there is at fault. Find a simple shape - cylinder, shot glass, vase, and print that as a base line.
I’ve printed pla cups that held water as well (didn’t use them though) using a hollow model and normal slicer settings.

(Electra Flarefire) #8

@raykholo I should have explained in the desc, this IS a shape that is designed to test the top layer waterproofness. The ‘bad bridging’ is intentional, so anything that gets into the infill will escape and show the problem. It’s actually harder to make this waterproof than ‘simple’ models where the wider or thicker bottom layer hides the problem as your infill floods.
The printer is now making waterproof models just fine with just two top layers. :slight_smile:

(Duplicat 3D) #9

@Electra_Flarefire
Spam? That would be a community owner’s decision.

(Electra Flarefire) #10

@Duplicat_3D That’s what I don’t understand. Your post wasn’t spam, I had to click ‘show posts marked as spam’ then unflag yours to have it show up.
My own comments seemingly randomly get marked as spam too on other people’s posts, even when the ‘spam’ is ideas/advice/genuine comments.

(Ray Kholodovsky) #11

That’s good. For your model to work best (ie not a test but a usable object) I would either print with pva support if dual extruders are available, or draft those bridges slightly to stagger them like upside down steps. And that way there’s no “tear out” from the bridging like there is now.

Btw when I’ve done what I suggested it involved creating the model using multiple solids then spinning a conical surface around that underside and removing certain fragments of solid under that threshold. Gotta love Autodesk Inventor.

(Electra Flarefire) #12

@raykholo it’s not meant as a usable object. It was created /purely/ to test for this and allow printer tuning. If you ‘fix’ the bridging it no longer works as intended.
The cup is someone else’s model: https://www.thingiverse.com/thing:159884
And prints fine and waterproof once your printer is working right. :slight_smile:

(Ray Kholodovsky) #13

I understand. I simply felt it was worth mentioning the process I go through for when I do want a “fixed bridging” model that prints without loose strands like that at the bottom, specifically to say it’s extremely complicated and tedious. It’s great that your machine “seals up” despite the intended handicap of the model.

(Electra Flarefire) #14

@raykholo thanks for the advice. I’ll eventually have a dual extruder to play with, but for now, I’m mostly playing with materials. Next is flexPLA and then it’s back to fighting to get nice prints with stringy, stringy nylon.

(Maxim Melcher) #15

with #PETG from #Winbo I can print by 180-200mm/s with my custom hotend. PETG needs a powerful hotend. Proof:
https://plus.google.com/112467558426863470913/posts/4r8A2epwbZ5

(Electra Flarefire) #16

@Maxim_Melcher I can run it at 90mm/s(Not tested beyond, I only have a Prsua i3, so the bed/head movement is the limitation) with the e3d v6 head(And I suspect more with the volcano on the big delta), but I loose the lovely translucency I get at lower speeds. And any flex or vibration in the printer also causes the same effect.
I need to test high vs. low speed strength, but it’s an interesting material to play with.
I’d be interested to see what the highest speed you can do and still get the ‘crystal’ look.

(Maxim Melcher) #17

@Electra_Flarefire Translucent works better with solid infill and layer thickness over 0,2mm (more is better). This is no my way, Ihave not enough time for 10 hours prints :). But my prints have translucent perimeters.