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How do we feel about PETG-GF? (forum.guncadindex.com)
submitted 7 months ago by to c/general@forum.guncadindex.com
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Someone recently turned me on to a new weird PETG-GF that is supposed to be very impact resistant and very affordable. I'm always interested in new materials, especially those that are cheap and easy to print in.

I use this "UFA compliant compact striker fired artillery boi" platform for material tests. If it's built well in PLA+, they will take a solid diet of high velocity 22lr with a standard printed breech.

This has been the best one of these I have built so far. I have ran shorts, standard velocity, high velocity, stingers, and interceptors. Extracts flawlessly. No signs of wear at all.

I'll take it out and run the hell out of it within the next couple of weeks.

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[–] 4 points 7 months ago (1 child)

If you're planning on putting a new filament through its paces, make it a lower for a direct blowback 9mm. AR-9, FGC, M11, whatever, but that'll be one of the more violent things you can do with it. That and an AR lower specifically for buffer tube interactions.

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  • [–] [S] 2 points 7 months ago

    I have done a couple other parts, such as hd22 barrel nuts, Glock mags, 10/22 mags, etc. I did some destructive testing with Glock mags and they held up really well.

    I don't do much with parts kits builds, and these little suckers are easy and cheap enough for me to build just as a test. I know what to expect out of them with other materials such as abs, PLA, and pla+. The breech, sear, and hammer are typical failure points for this particular build and get different types of stress.

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    • [–] 4 points 7 months ago (1 child)

    This thing could probably be a bit more accurate if the rear sights were attached to the barrel instead of the receiver.

    Then again, does it even have rifling at all? Maybe accuracy isn't much of a concern.

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  • [–] [S] 4 points 7 months ago

    It does have rifling, and it doesn't keyhole.

    And you are correct about accuracy in relation with the sight placement. As is, these will get you a 3" group at 20 feet on a good day, which is more than reasonable. I have an 8" pistol that I've hit steel @100 meters with a scope a few times, and the scope is mounted on the barrel.

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    • [–] 6 points 7 months ago* (10 children)

    The reddit post of this is typical reddit slop repeating the same incorrect "common knowledge" bullshit everyone else spouts. If the filament is strong enough then it's strong enough but it needs to be tested. Shattering is a nonsense excuse. Pet, ppa, pps, any high rigidity does the same and people are perfectly fine with using them.

    Some asa/abs cf/gf is similar in that it has better layer adhesion and impact than non filled. But they want to say how it's worse. Anything needs to look at the actual filament and not generalize. Also scientific progress actually improves new products. It's unthinkable to redditors.

    I can understand generalizing for beginners because there is so much to learn but it gets out of hand.

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  • [–] [S] 3 points 7 months ago

    People get real wild with the filament stuff for sure. I have one of these same builds in matte PLA, and PLA-F. My Modelo has silk PLA and normal PLA parts on it that are all original 2000 rounds later.

    I don't recommend people use these weird materials, but I like to put it out there for everyone just as another data point.

    My barrel nut for my 21.5" m4gery is this same PETG-GF and it's been working great. I broke my PLA+ barrel nut.

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  • [–] 3 points 7 months ago (2 children)

    Some asa/abs cf/gf is similar in that it has better layer adhesion and impact than non filled.

    Do you remember the brands by any chance? I'd love to give something like that a try. I like PLA+ but I really don't like its thermal properties, and some kind of ABS that behaves that way seems like it might be just what the doctor ordered, especially since ABS is usually like half the price of nylon.

    I bought a spool of ABS+ that on paper should perform similarly, but I haven't gotten a chance to try it yet and I like the GF/CF external finish.

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  • [–] 2 points 7 months ago (3 children)

    Filament testing has the same sort of dogpiling effect as bookerhookbangswitch posting.

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  • [–] 1 point 7 months ago (2 children)

    Wait what the he’ll is bookerhookbangswitch

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  • [–] 2 points 7 months ago (1 child)

    "Get your booger hook off the bang switch". As in, trying to enforce a gun safety law over the internet given one or two pictures absent context. More generally, it's just one of several surface-level things that redditors will scream about because it garners karma.

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  • [–] 1 point 7 months ago (1 child)

    For a long time, many people（such as reddit） have believed that PETG should absolutely never be used in 3D printed firearms. Is this reasonable and scientific? Furthermore, with recent improvements in PETG materials and the advancement of 3D printers, has PETG become a viable option worth trying?

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  • [–] 1 point 7 months ago

    Even in the past for petg, it depends on the caliber and design and I'd say the same with abs/asa, pet and and some others. It's still a better idea to use a better filament and have a larger margin of safety with more strength than you need but they can survive. I have seen several that have used petg over the years with 22 without issue. Larger calibers was more mixed. I personally still won't use it but I can afford to use nylons on anything I want to keep for a long time.

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    • [–] 1 point 7 months ago (2 children)

    Funny enough I bought a roll of petgcf after Hoffman's video recommending that over pc and pacf6 and never got around to doing anything with it. Are you taking any additional steps or precautions compared to pla whilst printing?

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  • [–] [S] 1 point 7 months ago (1 child)

    I think hoffman recommended PET-GF, not PETG-GF.

    But as far as differences, it prints just like PETG. I did have to run the nozzle at like 260C. It does require drying. It's abrasive, I ate 1mm off the face of a brass nozzle in about 300 grams of material. Steel nozzle has been gone for the remainder of the roll. It needs to be dried, but overnight @ 70C was plenty to get it dry and was good for a couple days afterwards. Nothing like drying nylon.

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  • [–] 1 point 7 months ago

    To be honest I don't recall if it was pet-cf or pet-gf either. But If drying and steel nozzles is the only additional attention that's required to get extra heat resistance with the same or slightly better strength,hardness and rigidity I'll try some!

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