3D Printing PETG or PLA?

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Greg Furtman

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I need to order some filament soon. I just bought an Ender 3 V2 printer. I'm trying to decide of I should order a spool of PLA or a spool of PETG. I just do hobby projects including rocketry and astronomy. So what is the best general purpose filament, PLA or PETG? I'd like your thoughts on this.
 

Karl

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If I'm right in thinking the Ender doesn't have a heated bed, go for PLA. It's plenty strong for most applications, easy to work with and there's a ton of options on the market in terms of colour & brands.
 

rharshberger

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iirc the Ender 3 v2 does have a heated bed, as long as the unit has the right configuration for PETG printing (ptfe bowden tube, heated bed, an the ability to heat the end to between 240 and 260C then it should be oka with PETG as well. PETG is a bit more difficult and requires making adjustments in the slicer to get it to print well, so far my PETG prints have not for the most part equaled the finish of my PLA prints. PETG IMO is better for rocketry stuff than PLA and it may be as good as ABS (ABS sands better though).
 

Greg Furtman

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If I'm right in thinking the Ender doesn't have a heated bed, go for PLA. It's plenty strong for most applications, easy to work with and there's a ton of options on the market in terms of colour & brands.
Karl, the Ender does have a heated bed so I can use just about anything.
 

Charles_McG

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I use PETG for rocket parts, or parts I want to do better with flex and impact.

I haven’t looked lately at PETG v various PLA Pro to see if they have caught up.
 

ghostfather

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PETG is my universal filament, and even then you can buy some special formulations, especially the high temp stuff for some things like tail cones.

I've found that polyurethane glue (Gorilla glue) works best if you glue PETG parts to anything, the kind that foams up a bit as it absorbs moisture from the air. Epoxy doesn't make a chemical bond, but works well enough if you sand the surface a bit, but then it's just a physical bond. PU glue makes a chemical bond to PETG
 

JoePfeiffer

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I use PETG (eSun brand) for everything. I've got several items I've printed that live in the cab and toolbox of my pickup truck, and I don't want them to melt in a New Mexico summer.
 

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I use PETG (eSun brand) for everything. I've got several items I've printed that live in the cab and toolbox of my pickup truck, and I don't want them to melt in a New Mexico summer.
PETG and ABS will not melt to my knowledge.
 

beeblebrox

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I need to order some filament soon. I just bought an Ender 3 V2 printer. I'm trying to decide of I should order a spool of PLA or a spool of PETG. I just do hobby projects including rocketry and astronomy. So what is the best general purpose filament, PLA or PETG? I'd like your thoughts on this.
The Ender3 does have a heated bed...above post incorrect. I highly recommend PLA+ I recommend eSun PLA+ or Eryone PLA. (Not PLA+but still excellent material) CHEAP PLA is brittle and inconsistent. Both print nice and have good strength. Better heat resistance than regular PLA. PETG is a pain to print, but if you can use this print profile (Below) for the Ender that works well for that. (for Simplify3d) If you don't have Simplify3d for slicing...get it. It is well worth the price. ($150) I struggled big time with Cura and Slic3r. ALSO, do yourself a big favor and get a PEI sheet for the build surface. It is far superior to using glass or whatever stock bed surface you have. I don't know what the New Ender has, but if its is like the Ender Pro that I have it is a removable flexible textured plastic sheet. That will work pretty good for PLA but it is terrible for PETG. If you go with the PEI sheet, which you can get custom made for the Ender from Tiny Machines. Assuming your Ender has the magnetic textured bed, you only need the steel backed PEI sheet, you don't need a magnet.


Advanced formula. Superior than all PLA on market.
The newly added mixes are also bio-polyesters and the the PLA+ is still 100% biodegradeable.
Major differences between PLA+ and regular PLA:
Elongation At Break: PLA+ 29% Regular PLA 5%

Izod Impact Strength: PLA+ 7KJ/m2 Regular PLA 4.2KJ/m2

As you can see the Toughness of PLA+ is superior than regular PLA.

 

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Greg Furtman

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I am currently printing with some Duramic PETG. Last night I tried a test print but I could not get it to adhere to my Ender 3 V2 bed. This morning I cleaned the bed with IPA and then sprayed some AquaNet All Weather ( so what makes a hairspray all weather?) hairspray on the bed & let it dry. I rechecked the levelness of the bed and started a PETG print. I have the nozzle temp at 245C and the bed at 75C. The first layers adhered well and the print job is doing nicely.

On another note O was thinking of buy a spool of Sunlu Silky Copper PLA. I like the looks.
https://www.amazon.com/dp/B07V7VHN2...olid=26823UM7TZ73K&psc=1&ref_=lv_ov_lig_dp_it

Has anyone used a silky PLA before? Any problems?
 

beeblebrox

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That was my point. I use PETG because it doesn't melt or warp at these temperatures.
Yes, True for PETG, however, printing is much more difficult. I have built several rockets with 3d printed fin cans, nose cones and fins. (Although I reinforce the fins*) I have not had any warping problems. My 2.7" Nike Smoke sat in the sun for an hour last year before flying, zero warping. Printed with PLA+ for the nose and fin can, Regular PLA reinforced with epoxy for the fins. The key is do not leave the rocket or anything else in the car with the windows up in the hot sun, 165° certainly can warp PLA. I do like the properties of ABS too, but...hard to print, need ventilation so you don't get the fumes in your lungs, and you need an enclosure for most things. I have made a Cell phone holder for the car, (I cloned the "Cup Phone" because I didn't want to pay $49.95 for it and it would not have worked right anyway.) That is PETG and has survived all of last summers heat plus this year so far...

*Reinforcing tips for 3DPrinted fins:
1. Print fins in vase mode, fill inside with low viscosity epoxy. (For small rockets.
2. Print the fin flat on the print bed as two "Halves" Glue them together with a piece of 0.030" fiberglass sheet in between. Super strong. The big issue with that is the layer lines...

IMG_20200717_111229456.jpg
 
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beeblebrox

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I am currently printing with some Duramic PETG. Last night I tried a test print but I could not get it to adhere to my Ender 3 V2 bed. This morning I cleaned the bed with IPA and then sprayed some AquaNet All Weather ( so what makes a hairspray all weather?) hairspray on the bed & let it dry. I rechecked the levelness of the bed and started a PETG print. I have the nozzle temp at 245C and the bed at 75C. The first layers adhered well and the print job is doing nicely.

On another note O was thinking of buy a spool of Sunlu Silky Copper PLA. I like the looks.
https://www.amazon.com/dp/B07V7VHN2...olid=26823UM7TZ73K&psc=1&ref_=lv_ov_lig_dp_it

Has anyone used a silky PLA before? Any problems?
That stuff looks great, but you need to do two things, run a little hotter and slow the print down to about 60% of what you were using. That stuff and also stuff with any kind of glitter etc can clog nozzles. Sunlu is good filament, had good luck with it. (I had black pla+)


Get a PEI sheet...
 

ghostfather

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.... Print the fin flat on the print bed as two "Halves" Glue them together with a piece of 0.030" fiberglass sheet in between. Super strong. The big issue with that is the layer lines...
I print fins with a void for a piece of G10 core, as most of my fins are airfoiled, either with a symmetric NACA airfoil if subsonic, or a symmetric Von Karman profile if going more than Mach. I epoxy the G10 core using thru-the-wall construction, and slide on the fin, gluing it with PU glue. That way, even if the printed fin should fall off, the G10 core would act as a fin, as it is about 80% of the area of the printed fin anyway.

I've also played around with the "two halves" idea, adding a couple of layers of wetted 80gr fiberglass between to glue them together, but the epoxy doesn't stick to PETG that well. I may try it with PU glue someday. It does seem fairly stiff with the fiberglass, and good enough for a minimum diameter rocket where you can't use thru-the-wall construction.
 

beeblebrox

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I print fins with a void for a piece of G10 core, as most of my fins are airfoiled, either with a symmetric NACA airfoil if subsonic, or a symmetric Von Karman profile if going more than Mach. I epoxy the G10 core using thru-the-wall construction, and slide on the fin, gluing it with PU glue. That way, even if the printed fin should fall off, the G10 core would act as a fin, as it is about 80% of the area of the printed fin anyway.

I've also played around with the "two halves" idea, adding a couple of layers of wetted 80gr fiberglass between to glue them together, but the epoxy doesn't stick to PETG that well. I may try it with PU glue someday. It does seem fairly stiff with the fiberglass, and good enough for a minimum diameter rocket where you can't use thru-the-wall construction.
That is another reason I hate PETG, it's like solid mold release to epoxy. I used industrial epoxy to bond to a sanded PLA surface, it sticks well. (Used Tap Plastics Slow cure resin, System Three is good too.)
 

Greg Furtman

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I ran into town to pick up a prescription, I was gone a little more than an hour. When I got home I saw that my PETG print had popped off the bed and I had a lot of spaghetti. After cleaning up the mess I cleaned up the bed & sprayed another, thicker layer of hair spray. Currently printing Take 2.
 

Charles_McG

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I use the Creality flex magnetic bed and have found aqua net to make PETG adhesion worse, not better.
 

beeblebrox

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I use the Creality flex magnetic bed and have found aqua net to make PETG adhesion worse, not better.
I use the Creality flex magnetic bed and have found aqua net to make PETG adhesion worse, not better.
I had the EXACT same problem, was tearing my hair out...

Note: use 90 degree bed temp...

Do yourself a huge favor... This will solve your problem. I use Purple glue stick. One application lasts for many prints. You actually need it as PETG sticks hard to PEI. PLA works very well too. I retired the Creality sheet. You do need to re level the bed as the PEI Steel sheet is thinner than the creality one.

$21.99 - Not expensive at all...

 

Joe Bruce

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I have used picture frame glass covered in blue painters tape for years with no issues on PLA or PETG. If you REALLY want it to stick, wipe down with 90% IPA first. Then you have to figure out how to remove the tape from the part!

Only exception was a HIGHLY detailed ornament where I had to slow the first layer WAY down (15-20 mm/s). Everything else adheres fine at 40-60 mm/s.

ABS has had more adhesion / warping issues, which is why I rarely print it. But I don't have an enclosure.
 

Greg Furtman

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The second coat of AquaNet helped & I'm getting decent adhesion with my PETG. One of the things I don't like about PETG is how stringy it is. And so far my first impression is to stick with PLA or PLA+.
 

Greg Furtman

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So after several failed attempts printing with PETG I finally did a decent print. I was getting a lot of stringing and places of glop on the top edge that would be enough to block the nozzle from moving. I found an article on All3DP that was about recommended Cura settings for the Ender 3. I followed those & got a good print. What did I do? Dropped the nozzle temp to 230C. Slowed down the print speed and I set retaction from 6.5 to 4mm.
 
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