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Thread: PET - not pet-g

  1. #1
    Super Moderator curious aardvark's Avatar
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    PET - not pet-g

    A while back (couple years maybe) I bought a roll of pet-g from technology outlet.
    When it came the reel said PET, Not pet-g.

    It's odd stuff claims to be black but is kind of translucent grey.

    And I've never really done anything with it.

    So decided to give it a try yesterday, been making tripod inserts with adaptors for various cameras on top.
    Figured I'd use the pet for the ipad holder.

    So first i ran my filament test. Attached.
    It's a small shape inside a larger shape. I place two a couple inches apart. This tests all the important things. The narrow gap between the two shapes tests short distance travel and retraction and the larger gap between the two models tests retraction over long distances.

    My first pet settings : 23oc print, 50c bed, 75mm's print speed - pretty much hit the sweet spot.
    Zero stringing, really clean prints.

    And the properties of the PET were really interesting.

    It's a lot more rigid than pet-g (which makes sense as glycol is a viscous liquid) and not as hard as pla. The small blocks were just about crushable, but did not split or shatter.
    In pla the small shapes are just totally uncrushable and in pet-g they squish like hard chewing gum.

    The larger shape in pet crushed, with some cracking and splitting - but NOT along layer lines.
    Pet-g - the large shapes just squash and look chewed.
    Pla - the larger shape resists until you put a lot of pressue on - then it explodes. Only did that once :-)

    So pet is firmly in the sweet spot between pla and pet-g.
    It prints easier than pla, and once I'd removed all squish from the print settings - sticks great to pei and removes pretty easy to.


    Table confirms my 'slightly' less scientific testing ;-)

    If I can get any more and it's a reasonable price - it could easily become my go to filament.

    Quite why pet-g became the member of the polyethelene terepthalate family to become popular I don't really know.

    Oh and this stuff has been sitiing on a shelf in my workshop for at least 2 years. No moisture issue.

    My ipad mount builds out at a pretty steep angle - and was absolutely perfect at 0.3mm.

    the base width is 43mm and the top width is 100 mm, with only 20mm vertical build.

    Even at 0.3mm layer height the underhangs were smooth and issue free.

    Sooo, I'm currently printing one with 130mm width


    Still printing at 0.3mm :-)
    So we'll see what the underhangs are like.
    By rights they should work, but I'd expect them to be a litle rough. we'll see.
    Might be able to go woder still - though the 100mm grips really well, so from apurely practical point of view I can't see anything wider than 130 being necessary.
    But I am curious to see just how wide I can go :-)


    It's a friction fit so the wider the arms the larger the area that's gripping the ipad. (it's an old ipad pro 9.7 my mate gave me - great camera)
    Got a timelapse video of the 100 being printed, the ipad was being held in the 80mm first one.

    Don't have alightning cable in here yet - so I'll upload later.

    Right now to see if you can still get PET filament.

    ***

    Yep - this looks about the best deal i can find: https://www.amazon.co.uk/ICE-Filamen...4420675&sr=8-6
    only 750g, but at £18.99 - not an awful price.

    And most stuff on amazon that just says PET in the title - is actually pet-g as it tells you in the description.

    Oh and apparently it's hydrophobic - so zero moisture issues - ever !

    I'll do some speed printing tests after this mount has finished.
    But given how clean it prints at 75mm/s - I can't see any issued with 100 or 150 - we will find out :-)

    On the 130mm mount front - there have been some crunchy noises coming from the printer. Print is still attached so i suspect I've had a little curling at the ends of the arms that are being caught on the metal, fan channelers. It Looks fine and print has not detached (what those noises usually precede) YET ! lol
    Attached Files Attached Files
    Last edited by curious aardvark; 11-03-2020 at 11:47 AM.

  2. #2
    Super Moderator curious aardvark's Avatar
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    I'm totally out of clear filament - so ordered some icefill clear pet. £18.54 for the 750g roll on my amazon prime delivery.

    So just shy of £25 for a kg.
    Oh and it's food safe as well.

  3. #3
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    Hmmm, doesn't seem to be available in the USA.

  4. #4
    Super Moderator curious aardvark's Avatar
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    https://www.amazon.com/taulman3D-T-G...ustrial&sr=1-1

    https://www.amazon.com/Taulman-1-75m...ustrial&sr=1-2

    basically taulman t-glase is actually PET (they add an extra T for no obvious reason.

    I have to say it's pretty weird why the industry went with pet-g when PET pretty much beats it in every practical application and is so much easier to use and store.
    for me pet-g is really too soft for most applications. for places where pla is too hard, PET is an ideal substitute.

    Still haven't found any glass point temps. - Ah okay about 80c - so same as petg.

    And the longer ipad holder printed fine.
    the angle of that underhang is amost exactly 45 degrees. According to my angle measureing plastic doohickey :-)

    Not going to bother doing a longer one as that works just fine.

  5. #5
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    I saw this question and response on the T-Glase page at Amazon:
    Q: Is this petg or abs? the title says petg, but the "material" says abs.
    A: This is a PETG filament.
    By taulman3D on February 25, 2019

    But they've changed "material" to PETT. I've sent them a question asking what the difference is between PETT, PET, and PETG.

  6. #6
    Super Moderator curious aardvark's Avatar
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    all the descriptions call it pet.
    First, t-glase is made from the highest optical quality PETT material
    It's a defintely not pet-g but a co-polymet of pet. Basically pet gets cooked to add the hydrophilic ability and increase the strength, the crystallisation which also makes it less opaque and more transparent:
    Depending on its processing and thermal history, polyethylene terephthalate may exist both as an amorphous (transparent) and as a semi-crystalline polymer. The semicrystalline material might appear transparent (particle size less than 500 nm) or opaque and white (particle size up to a few micrometers) depending on its crystal structure and particle size.

  7. #7
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    According to this page, PETT is different from either PET or PETG:https://3dinsider.com/pett-filament/...0more%20rigid.

    PET= Polyethylene Terephthalate

    PETG = Polyethylene Terephthalate + glycol

    PETT = Polyethylene coTrimethylene Terephthalate

    It seems that PETT is more like PETG in most respects, but is hydrophobic like PET, which is an advantage. Since plain PET doesn't seem to be available here, I think I'll give PETT a try.
    Last edited by jamcultur; 11-05-2020 at 05:08 PM.

  8. #8
    Super Moderator curious aardvark's Avatar
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    I have used a co-polymer - was incredibly strong stuff. I was making micro gears with it. 1mm thick and culd not snap them.

    It really is very strange why PET is in such short supply.

    My icefil stuff arrived couple days ago - so I might have a play with it today and see if it's the same as the anynomous stuff I'm currently using.

  9. #9
    Super Moderator curious aardvark's Avatar
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    the interesting thing with the original roll of pet. is that the first 2-300gms, printed as well as any pla.
    But now it's run down a bit it's got a bit rubbish. Stringing and a little blobbing.

    I think it actually NEEDs exposure to air and humidity to 'mature' and improve.

    So I've switched back to pla for a bit lol
    Tempted to leave the pet outside for a few days and see what happens.

  10. #10
    I also tried Taulman T-Glase PET, hard to handle compared to PLA. Good for vases. (PET Review)

    PET-Filament-Review-Pros-and-Cons.jpg

    I find it is a different material compared to PETG. (PETG Review)

    PETG-Filament-Review-Waterproof-Dishes-For-Planters-768x432.jpg

    What I have have found out that some recycle companies struggled/struggle to recycle both materials together as:
    "Recycling PET and PETG together though gives a headache for recycling companies. Due to the different melting temperature requirements, PETG melts before PET and sticks in solid chips forming large clumps. This causes a problem when recycling those two materials together."

    And yes indeed I had to raise temperature to 240-250 C to achieve clear shiny (semi transparent) result for Taulman T-Glase PET compared to 230 C for PETG.
    PETG is less brittle compared to PET.
    Both materials will leave a lot of stringing if there is a lot of retraction.

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