What build surface for PETG?

  • Hi all,

    I've not done a lot with PETG, as I've always gone more for ABS.

    I've bought a corexy kit and need to print some parts in PETG, and to my surprise I'm getting a bit of warping and lifting off the build plate, which I thought PETG didn't do.

    I've tried it both on my open Ender 3 pro with the flexible magnetic sheet surface, and in my enclosed Duet converted Zortrax on Printbite. Both have lifted a bit.

    Print quality on both are beautiful, and I'm running 240/230 at the hot end and 70 for the bed. Fan at only 20% after a few layers.

    No stringing or globs, extrusion ratio and first layers are perfect.

    I can't remember having any issues other than stringing/blobbing in the past, and was moving to this material so I could do larger prints on open machines without warping.

    It seems to be sticking better to the E3 Pro textured mat. I'm thinking it might actually be pulling the flexible mat up a bit.

    Please share some of your tips with me.



  • I am printing on PEI and no lift problems whatsoever. (PLA, PETG, and flexibles).

  • I have no issues with PETG. I would suggest that you try a higher bed temperature, at least 80C, and that you turn your fan off.
    I print on glass with no adhesion enha\cement (ie just plain glass)

  • Cheers guys!

    Yep, fan off and hotter bed was where I was going next. And yes, I have absolutely no problems with PLA whatsoever on this rig.

    Are you both printing on open machines?

  • administrators

    I print PETG on PrintBite heated to 80C. I've heard that PETG sticks to plain glass rather too well.

  • I print tonnes of PETG and something that I realized the hard way early on is like pla and abs, not all petg's are made equally. Some print super nice with basic settings and some need excessive work in my experience. But in all cases, I've never had peeling problems printing on glass or aluminum beds with a piece of Kapton tape. You can usually get pretty high mileage out of it too if you get a quality tape. I definitely do not recommend printing directly on glass. Youll have lifting.. more lifting and all of a sudden like DC42 says, its sticks and sticks too well. I've taken chunks out of glass beds! Youll need to remove it by heating your bed to something high like 115c and destroy your part to get it off the bed without chipping the glass.

    And for warping, I don't get any of that printing inside a fully enclosed build chamber where the ambient temp is around 45 with a 85c bed temp.

  • My PETG printer is closed on all but one side but I suspect it isn't going to make much difference.
    Yes, too much adhesion can be a bit tricky. It's a fine balance of bed heat and less (compared to PLA) first layer squish.
    In addition, this printer is a 300*300 printer and 12" * 12" mirror tiles are inexpensive and fit perfectly. The glass does last a substantial time before divots are taken out.
    Oh ... never try and force the new print off while the build plate is still hot.

  • Moderator

    PETG on PEI for me sticks too well, so I use glue stick to let me get a blade under and it pops off when cool.

  • @Corexy said in What build surface for PETG?:

    Are you both printing on open machines?

    Yes, open machine, bed t 60c, fan off or at 30%, and 1mm pei sheet with 3M adhesive.



  • PrintBite 80-85C and I love it. I have a few 12cm fan's on the frame that start blowing after the print is done to cool it off, when printbite cools down to 30-35C the part just pops off. I use PrintBite also with PLA, ABS, HIPS, ASA, PC and PA. The only thing I don't use PrintBite with is TPU 'cause TPU gets almost impossible to remove from PrintBite so I use bluetape to print TPU

    PETG sticks good to plain glass but will often break glass when you try to remove the print (not matter how cold the glass get) so I used to use hairspray or gluestick on glass in order to be able to properly remove the part. That does it and work nice only it's messy.

  • i used this glue on heated glass


  • @arhi said in What build surface for PETG?:

    ... TPU gets almost impossible to remove

    A trick that I use to remove TPU from PEI, when the print completes, put a few drops of Isopropyl alcohol on the boundary between the print and the bed and somehow it makes it much easier to remove.

    (previously I used to spread a tiny amount of baby powder on the bed before printing TPU but a friend told me about some health risks with baby powder so switched to IPA and it works like a charm).

  • @zapta tried many things (including IPA) but printbite grabs on to TPU so strongly it's impossible to remove it. Actually, it depends on the TPU, I have some TPU that's not a soft as ninjaflex but much much harder (still very soft) that I can remove from the printbite, but stuff that's super soft is impossible.

    It is not a big deal for me, I just put a 2mm aluminium sheet covered with painters tape (I use some beige one that's el-cheapo here, not the fancy expensive uv resistent blue one) or 4mm glass covered with painters tape directly over the printbite and print, no even need to heat it up in most cases 😄 .. and since I use nozzle as the Z probe there's no need to worry about z-height.. but I also print TPU very very very very rarely as a stand alone object, in most cases if I need to print TPU I print it on top of ABS or HIPS so the print surface is not a big deal and I want the first layer to fuse as much as possible 😄 .. but that's a whole other story

    ah, and forgot to say, printbite does not really love IPA!!! there's some residue IPA leaves that makes it less effective, so after using IPA I need to clean printbite with acetone 🙂 .. almost forgot that 'cause I rarely need to clean printbite at all as unless you touch it with your fingers it just works 😄

  • I use Borosilicate Glass (I use this to prevent bed warpage) with buildtak flex system. I use hairspray on the buildtak as PETG tends to stick too well. Bed temperature of 80-90 and nozzle temp 240. NO COOLING FAN. As people have mentioned in the post not all filament is the same. Be also careful of the layer heights and the larger layer heights and print widths can also cause larger shrinkage and cause some warping. Lower layer heights give the part a chance to relax between layers.
    My build surface is 300 x 600 and i have done prints to almost full bed size with PETG...

  • Thanks all!

    80 bed with 240/230 nozzle and no fan gave a much closer result to flat, almost perfect.

    Tiny bit of stringing, but nothing to worry about.

    I'm using 0.5mm wall thickness, so I might drop that down to 0.44 and up the bed to 85. Might even drop the print temp to 225 as well, just to see if that removes the strings.

    I must add these prints are pretty good, even spectacular if I say so myself, but I'm just being picky because why not. They are machine parts for my new printer, so I want them to be perfect.

    Funny how literally every article on the net recommends fans running flat out. I never recall PETG warping on me before either, so I might try a roll of Esun I've got sitting here as a reference.

    Cheers again for all the helpful tips!

  • some brands will have issue with fan's some brands will allow you to run fans at 100% ... I personally run fan's at 20% during "normal" print and 100% during bridging/overhangs

  • My go to print temp for the bed is 75c (works for me might not for others)

    I print primarily on ultra-base style bed surfaces, including the creality version.

    And I put a whiff printafix on purely to make it easier to get the print off and not damage the print surface

  • I print PETG on PEI sheets or powder coat. The key is to print the first layer cold and pick the temperature based on how you want it to stick. Hotter sticks harder and colder pops off easier. I typically start at 60C for the first layer then switch to 80C for the rest of the layers to minimize warping. You'll need to tune this for your specific print bed.

    I also run the hot end <230C on the first layer to avoid damaging the PEI, then ramp up the temperature for the rest of the print. I typically run 245-265C with fan for speed, overhangs, and layer adhesion. Then keep stringing in check with aggressive filament drying.

  • @BotLawson said in What build surface for PETG?:

    Then keep stringing in check with aggressive filament drying.

    How do you try PETG? Time, temperature, equipment, etc?

  • @zapta, I use a food dehydrator, 70-75 C overnight (6-8 hrs) but never had real issues and I am less than a mile from the Pacific Ocean ...

  • @zapta I store and print out of "dry cartridges" with A4 Molecular sieve desiccant. https://www.thingiverse.com/thing:3225037 I've made 8 so far.

    They're a one time cost as the desiccant generally lasts years and can be recharged if needed. (rapid temperature cycling will pump air into the cartridge and saturate the desiccant)

  • @BotLawson said in What build surface for PETG?:

    I also run the hot end <230C on the first layer to avoid damaging the PEI, then ramp up the temperature for the rest of the print. I typically run 245-265C with fan for speed, overhangs, and layer adhesion. Then keep stringing in check with aggressive filament drying.

    All well and good but sometimes, just sometimes depending on the brand of PETG, Colour & Other variables, set in stone Temperatures all go out the window.

    You only need to look at a few threads on this forum for confirmation of what I am saying, you should never (even with a known brand of filament) rely on a set printing Temp, you should always print a temp tower at the start of a new roll and work from the "look" and print at the arbitrary number that the temp tower shows to be the best.

  • Thank you all very much for your assistance.

    Stumbled onto a funny trick that gave me perfect adhesion, found it in the Prusa forum.

    I was really wondering what the hell was going on...I was heating my flexible magnetic mat so hot I couldn't remove the thin brims, yet the print was still lifting.

    What really go me thinking was when I tried wiping some metho on the mat (because you can't use acetone with it) and the problem got way worse, almost un useable. I was noticing it dragging up the first couple of mm of a layer despite my level/height/retraction being checked and good.

    Then I found a post that said that PETG hates being printed on a surface that has been used for PLA, as it leaves a sugary residue of some sort, and that dishwashing soap was the magic cure.

    I took the plate into the kitchen, put some soap on it and swirled/foamed it around with a really soft brush rinsed in warm/hot water, then rinsed it off in the same water. It came up really clean. Patted it dry with kitchen paper and heated it up to 80 degC (I was up to 90 in the end). It was clean as, and a lot of residue was gone.

    Perfect adhesion! I'll do this every time I swap to a different material.

    Hope that helps someone.

  • administrators

    I find printing PLA on plain glass much the same. If I clean the glass with IPA then it won't stick. If I wash the glass in hot soapy water and dry it with a paper towel, it sticks well when heated and releases when cooled.

  • @dc42 said in What build surface for PETG?:

    I find printing PLA on plain glass much the same. If I clean the glass with IPA then it won't stick. If I wash the glass in hot soapy water and dry it with a paper towel, it sticks well when heated and releases when cooled.

    It's all about those fine traces of oil or whatever I guess.

    I'm going to try it on my Printbite surface, as it's about 4yo and been troublesome recently

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