Alternative thermistor

Discussion in 'E3D-v6 and Lite6' started by paultnl, Sep 20, 2015.

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  1. Mike Kelly

    Mike Kelly Volunteer

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    I removed mine. No sense in arguing it. I'm having a friend with one conduct an experiment to see how hot the leads get for analytical data. As the PTFE has added insulation from the epoxy I'd be willing to believe the leads would be cool enough to touch because of the low surface area and reduced thermal transfer.

    That said, we should be hesitant to spread information that can fuel paranoia. The 3D printing world is already ripe with paranoia and we need to be sure to only spread information we know to be true. Not a bad feeling we get.
     
  2. paultnl

    paultnl Member

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    Update time.
    I still like the idea of these units but I have had a couple of failures as the wires are very delicate and they tend to break where it enters the epoxy. I now plan on reusing the brass screw using the E3D thermistors and fiberglass sleaving using something like this http://www.jbweld.com/products/highheat-epoxy-putty

    Any comments or suggestions before I start?
     
  3. elmoret

    elmoret Administrator

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    That epoxy is rated at 400F, which is only 204C. It does not seem suitable unless you are printing PLA exclusively and even then, it is borderline for some PLA formulations.

    It seems my original comment about strain relief proved true. It is important that thermistor wires are not allowed to flex, they should be fixed rigidly to the print head and the flexing should be done in the wires that are rated for it (the ones that connect to the thermistor leads, not the thermistor leads themselves).
     
  4. paultnl

    paultnl Member

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    Thanks for the feedback, I was getting my Cs and Fs mixed up. How about this stuff? http://www.amazon.co.uk/TEMPERATURE-ADHESIVE-EXHAUST-FIREPLACE-COLLECTORS/dp/B006U5K9EQ

    I don't think it was a strain relief issue per se as I zip tie the wires to prevent flexing, but if you get a print failure that causes a large glob of plastic it is very easy to damage the fine wires when cleaning the mess. I think the GF sleaving and possibly some kapton will alleviate this. Possibly not but that is what experimentation is for.

    The well in the brass screw looks quite deep so I wonder if it would be an idea to put a small amount of thermal compound in the bottom before the glue.

    Once again any ideas or feedback welcome.

    I will do my best to document the rebuild but am not sure of my photography skills on something so small.
     
  5. elmoret

    elmoret Administrator

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    Reviews on that don't look so hot:

    I bought this product for use on my exhaust manifold. The Fluke temperature readout was 230 degrees, nearly a thousand less than the rated temperature of this product! To my disgust I found that the "glue" carbonised after five minutes!!
     
  6. paultnl

    paultnl Member

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    Good feedback, I will keep looking then.
    Though as I will be buying this in the UK from a UK supplier our trading standards laws would make such mislabeling unlawful.
     
    #26 paultnl, Oct 23, 2015
    Last edited: Oct 23, 2015
  7. paultnl

    paultnl Member

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  8. Tincho85

    Tincho85 Member

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    Found it: https://measuretech.com.au/electric...lly-conductive-high-temperature-adhesive.html
    $344.44 I think the currency is Australian Dollar, $252 USD.. still too expensive for my taste.

    This one might work, don't know if it's thermally conductive though...
    http://www.permatex.com/products-2/...epair/permatex-muffler-tailpipe-sealer-detail
     
    #28 Tincho85, Dec 6, 2015
    Last edited: Dec 6, 2015

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