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Soft metal gasket for hotend?

Discussion in 'Mods and Upgrades' started by Ben R, Feb 3, 2015.

  1. Ben R

    Ben R Active Member

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    Ive broken 2 hexagon ends due to ... Well really due to clumsiness ... Hotness and trying to get the hot end tightenough to not leak. I dropped one, but it was stripped and unhappy...

    So has anyone tried adding a sacrificial metal gasket o-ring type thing in there? Its copper against??? Steel??. Aluminum washer in the middle should deform enough to get a better seal.

    Has to be hard enough to not deform into the filament path... But soft enough to work as a gasket. Also... Obviously... Heat resistant to 300c or so. An adhesive is out, as it would make separating the parts hard and possibly clog the filament path. Normally a place for a copper crush washer... But soooo tiny.

    Actually... Engine adhesive might work... That brown goo ya glue airplane and vw engines together with. Looks like molasses. Permatex 80017.
     
  2. milks

    milks Member

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    Not too sure where you intend to put this gasket, where the nozzle screws in to the heatbreak? I use copper silicone to glue the thermister into the hot end; it peels off easily if you need to take it apart and is good up to 300C. I think it might be the same as the brown goo you describe. Shouldn't be necessary though.

    Getting the nozzle screwed in tightly is a fiddle, it took me several attempts at around 270C. Lots of singed fingers, but it's been solid ever since.
     
  3. Mike Kelly

    Mike Kelly Volunteer

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    The brass nozzle acts as a gasket against the stainless steel heat break.

    Adding a gasket only adds additional points for leakage.
     
  4. Ben R

    Ben R Active Member

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    Well.. yea, you get one more surface... Regardless of potential to leak, gaskets do get used widely with good effect. Rarely do you see mating parts expected to carry "liquid" without some sort of chemical or mechanical seal. I can't think of ever seeing one.

    My "stock" hex hotend has a copper (or copper alloy ) nozzle with chrome on it. Well.. it had chrome on it.
    Regardless of how I tighten the hotend. Its a bit of a crapshoot and/or burned fingers if it will work without leaking.

    And no... permatex isn't silicone at all. It looks and almost smells like treacle. Used to glue metal parts together with a bit of a gasket seal. used on radial engines or other things with "jugs" and gluing VW engine blocks together. Looks like the temp is a little low on it.

    I'm trying to get a good seal without having to burn my hands... as that is rediculous! Currently using an J-head with PEEK tube I modified to fit. SOOO nice compared to the hexagon... but!.. it means i can't hit the temps I want to till I get my replacement or other replacement. Thinking ahead to my new leaky hex head. Try not to break the thin little metal tube on this one by getting it sealed so I will never have to open the top. I occasionally replace nozzles or get the rare clog (I'm a lot better than I used to be, not a huge problem now) but it still comes up on occasion.
     
  5. Mike Kelly

    Mike Kelly Volunteer

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    It was brass, which is copper and zinc, and the heat break is made of stainless steel.

    How are you putting your fingers anywhere near it? There's 2 tools required and I've never burnt myself on the countless times I've swapped nozzles on the e3d.
     
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  6. Ben R

    Ben R Active Member

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    How do you position it to use said tools.
    That tiny wrench ...are you wrenching on it while its still on the plate? I can't get it to work without using a third hand of some sort. In an attempt to not strip the hexagon side, I generally screw that in and then heat and cinch the nozzle.
    Regardless... its a design on which needs improvement could be made.. At its best on both of mine, i've had a tiny slow leak.. at least till the PLA baked to a sealant.
     
  7. Mike Kelly

    Mike Kelly Volunteer

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    Yes I wrench it on the plate. Though the E3D series doesn't have the flats like the hexagon so I use an adjustable wrench to grab the heater block.

    Make sure the nozzle is not seated up against the surface of the heater block otherwise it will be difficult to seal.

    I agree it's not the easiest method, but it's a proven and reliable method when done correctly. I hear rumors of people working on alternative methods that can be done cold.
     
    #7 Mike Kelly, Feb 4, 2015
    Last edited by a moderator: Feb 4, 2015
  8. Ben R

    Ben R Active Member

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    kinda what i'm thinking here. Not able to produce a new hotend.. but.. I'm gunna come up with something to make a more reliable seal. I haven't found a BETTER alternative yet. All metal is where its at.
    I did order a mk8 extruder... I liked the design of the hotend.. in theory anyway, and the direct drive extruder... anyway.. something I'm going to try to try. But don't want to throw away the original design. Someone put time and effort into it.
     
  9. Mike Kelly

    Mike Kelly Volunteer

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    The prometheus is about as close as you can get to a cold seal nozzle. Though if you only print with PLA, a J-head is a better hot end
     
  10. Ben R

    Ben R Active Member

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    yea.. going with one very similar. I also don't like the tiny tube in the hexagon.. I've broken 2. More of an accident type breakage.. but I'm prone to that. cleaning off plastic.. knock it off the table.. pipe is done. Those threaded tubes are replacement parts
     
  11. Mike Kelly

    Mike Kelly Volunteer

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    You might have saw my reply before I edited in the comment about j-heads.

    The benefit of the heat break is you get a sharper transition from cold to melt zone so you get less ooze and thermal expansion of the filament making extrusion easier.

    J-heads are ideal for PLA because the Teflon mitigates any crystallization in the PLA before extrusion
     
  12. Ben R

    Ben R Active Member

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    I didn't see the thread... but man.. thing is printing beautifully!
    The bottom is PETG, the brown is PLA One of my nicest PLA prints.. no ooze.. Birdfeeder 3.0 Printing the rest in ABS and its coming along beautifully too. It clips together, so no need to worry about gluing different materials.
    If i could just get a safe 240 out of the Jhead. PET oozes like mad.

    (note.. the things that look like fat layers is just a bad photo. Its as good as I've ever seen a print on an FDM machine.... which I owe in great part to you and this forum.. and a lot of hours in adjusting, testing and S3D)
     

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  13. Mike Kelly

    Mike Kelly Volunteer

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    That looks fantastic
     
  14. Ben R

    Ben R Active Member

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    I'm pretty happy with it.
    One of the few things the wife has demanded out of the printer. The family usually demands crazy things that are a pain to print. First thing... can you print this. Like.. day 1.
     

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