Glueing broken Butternet capacitors a fix or not?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by AK5B, Jun 16, 2021.

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  1. AK5B

    AK5B Ham Member QRZ Page

    Just noticed an ad in the Swap Meet for an HF6V / 9V coil and cap assembly---while I don't need it (I have an old HF6V with new caps stashed away for a rainy day) it made me curious as one of the caps with the coils had come apart.

    These Butternut doorknob caps appear to be glued together, so I'm wondering if simply putting some epoxy on the silver flanges and applying pressure would be a good fix or not. I suppose it could alter the capacitance slightly due to the additional dielectric added in the process, but would like to know either way.

    73,

    Jeff
     
  2. W9GB

    W9GB Ham Member QRZ Page

    Wishful thinking …. of a good repair. I would just replace it.
    Several sources available: DXE, High Energy Corp., Russian surplus, 2 Chinese mfg.)

    Butternut and Bencher originally sourced these HV “Door Knob” Capacitors from USA mfg.
    High Energy Corporation (HEC), Pennsylvania
    http://catalog.highenergycorp.com/category/ceramic-capacitors

    High Energy Corp. (HEC)
    PO Box 308, Lower Valley Road
    Parkesburg, PA 19365
    phone: +1-610-593-2800 , fax: +1-610-593-2985
    sales@highenergycorp.com
    ==
    The Butternut HF-series verticals used 200 pF and 67 pF High Voltage “Door Knob” Capacitors. DX Engineering has sourced replacement HV Capacitors from foreign manufacturers, as noted in photographs and size/form factor.
    Notice that DXE also swapped the more common 68 pF value (for original 67 pF).
    https://www.dxengineering.com/search/brand/butternut/product-line/butternut-antenna-replacement-parts/part-type/hf-vertical-antenna-replacement-parts
    CDB2D743-24ED-434C-9F42-702441719F16.jpeg F24F97DB-A67F-49E5-876B-6C24B8F85008.jpeg
    Knut, OE4KSF experience sourcing issues from HV Stuff in 2020.
    https://forums.qrz.com/index.php?threads/warning-about-hvstuff-com.723609/page-2

    HV Stuff , former Xi'an high voltage ceramic capacitor factory (Gansu, China)
    Jiuquan, Gansu New Energy Industrial Park
    Gansu province is in Northwest China
    http://hvstuff.com/
    ==
    High Voltage RF Capacitor Manufacturing (Shenzhen, China)
    This is a DIFFERENT doorknob HV capacitor manufacturer.
    http://www.hv-caps.com/products/H-F-RF-Power-Capacitor/2012/0223/106.html

    HVC Capacitor Manufacturing Co.,Ltd
    9B2, TianXiang Building, Tianan Cyber Park
    Futian, Shenzhen, P. R. C
    Tel: +86-755-61167757 Fax: +86-755-23997722
    Mobile: +86-13689553728
    E-mail: sales@hv-caps.com , hvcaps01@gmail.com

    18 months ago, I purchased a few replacements, at 68 pF (Russian Surplus),
    from an Eastern Europe reseller (eBay). Arrived after about 3 weeks (International shipment).
    Just search eBay and you will find different Eastern European resellers.
     
    Last edited: Jun 17, 2021
    KD0CAC and KK9W like this.
  3. AK5B

    AK5B Ham Member QRZ Page

    Thanks for all that, but as I mentioned above, I do not need another cap. I merely want to know if my epoxy idea has any merit in terms of putting a doorknob back together or not.

    73,

    Jeff
     
    N8TGQ likes this.
  4. W9GB

    W9GB Ham Member QRZ Page

    This is the QRZ Swap Meet photo, you are referencing?
    966DF4A9-8958-4694-9FE4-D71502B5EE9F.jpeg

    An Epoxy is an Insulator.
    This “break” appears to be in the Conductive structure of the 200 pF doorknob capacitor.

    3M Scotch makes an Epoxy for potting and encapsulation, DP270,
    BUT it is Expensive (~$21 to $25 /tube) and Non-conductive.

    https://www.3m.com/3M/en_US/p/d/b40066438/

    qSo, again, my answer would be NO.

    greg, w9gb
     
    Last edited: Jun 17, 2021
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    From experience trying to repair these, I believe it hasn’t much merit. If it works for you, that would be great but it never worked for me. If you have an LCR meter or something that can measure capacitance, you might give it a try and see what it measures.
     
    AK5B likes this.
  6. KD0CAC

    KD0CAC Ham Member QRZ Page

    It looks to be the electrical connection , so what ever you use should be a conductor [ metal mixed with the epoxy ] .
    Not an insulator / no electrical connection .
    I've seen and used all kinds of silver impregnated products for mostly circuit board stuff , do not have any recommendations though , do some research and try / test , as mentioned above .
    You might measure the cap as is , and then after reattaching to compare ?

    Does hurt to try , just a little time , a few bucks - and then you know .
     
    AK5B likes this.

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