Exothermic Ground Rod

Discussion in 'Amateur Radio News' started by N5HZR, Sep 1, 2018.

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  1. WB4OZM

    WB4OZM XML Subscriber QRZ Page

    Nice video and nice first attempt, BUT, the ground rod(s) needs to be 24" minimum below grade to work efficiency for lightning( and have many of them if using a 8' ground rod, placed 16' ( Optimum Spacing 2X Rod Length) away from each other). RF it's best to have 3/4" or larger for more surface area( like 3" copper flashing)
  2. KV6O

    KV6O Ham Member QRZ Page

    Compression connections are used much more these days, but require a special tool; not practical it you only have a handful of connections to make.
    NL7W likes this.
  3. N2FRA

    N2FRA Ham Member QRZ Page

    An oxy-acetylene torch brazed connection IS an exothermic bond. It is the same process only using a different heat source where the brazing material and flux are applied separately. When performed properly, a torch brazed joint is just as effective.
    WQ4G likes this.
  4. KG4BFR

    KG4BFR XML Subscriber QRZ Page

    Multiple lightning strikes .......really......I have lived in Miami most of my life and have not been struck ....
  5. W1YW

    W1YW Ham Member QRZ Page

    In the old days, when kids learned to do this, we called them: 'future rocket scientists'.

    Now we call then 'terrorists' :-(

    I must confess that used only as prescribed....nothing beats the smell of thermite in the morning.

    And no boys and girls, Uncle Chip is not going to tell you how to make thermite. The problem is that the reaction keeps on going until it runs out of oxidizer. So you can't extinguish it with conventional means. That means its dangerous if you don't know what you are doing.

    Buying the welders, for that purpose shown, is far more controlled.

    Last edited: Sep 3, 2018
    N5HZR, W7GST, K8XG and 1 other person like this.
  6. KC2SST

    KC2SST Ham Member QRZ Page

    Besides thermite, I still enjoy Nitrogen Triiodide, and really who can resist a big old batch of flash paper? At least Picric acid has that "hazard yellow" color already baked in.
    NC7U, WQ4G, W1YW and 1 other person like this.
  7. W2WDX

    W2WDX Premium Subscriber QRZ Page

    I always love the "Been doing it that way for years and never had a problem" or "My insurance looked at and said good job" comments. Doing it that way for years doesn't make it right or effective. Soldered or brazed connections will not withstand the voltages of lightning. One strike, maybe two ... and after that ... ZORCH!

    And as far as your insurance company, now they know they don't have to pay a claim and can simply deny you. Of course they said "good job" ... for them. Any work performed not to NEC anywhere nationwide (local codes do not matter to underwriters, NEC does) means they have the justification to deny a claim. Insurance companies only make money when they can deny a claim, paying a claim is a cost they do not want to incur at any time. So yeah ... good job for them.

    I just built a new station at a new QTH. All ground connections are exothermic. Used the same system in the video. I have four 8' rods on the property, two for antennas, one for the AC power service, and the last for the station. All are bonded with buried #4 bare copper wire exothermically, including the 2" solid copper straps coming into the station to the 3" wide, 72" long, .25 thick copper bussbar that all the equipment is grounded to with .5" solid copper strap. Whatever hardware there is (for suppressors and such) is all 316 stainless-steel. It just doesn't make sense to do it any other way. Penny wise, dollar foolish just isn't my thang! :D

    If my insurance company saw it, they'd say ... "Damn it!"
    Last edited: Sep 3, 2018
    N5HZR, K8XG, KD8DWO and 1 other person like this.
  8. W9AC

    W9AC Subscriber QRZ Page

    >"Exothermic welding can withstand multiple lightning strikes undamaged where often a clamped connection just blows apart."

    A well-connected bond using 15% silver solder bars and an oxy-acetylene torch can achieve results identical to Cadwelding. The reason it's not specified in NEC nor local codes is that it's susceptible to too much variability in the connection. Like welding, achieving consistent results with soldering is as much of an art as it is science. The objective is to remove as much art as possible to achieve a consistent result. Cadwelding mostly meets that objective when the user follows the manufacturer's instructions.

    I use both methods. There are some connections that are more conducive to silver-soldering. For example, if I need to joint two #2 solid copper wires, I place two bronze split-bolt connectors on the wires. I could stop there and meet code. But, I also silver-solder the joint in between the two split-bolts. It can be buried for eternity without future inspection, and there's no need to fear that the split-bolts have loosened or blown apart over time.

    Paul, W9AC
    WQ4G likes this.
  9. WQ4G

    WQ4G Ham Member QRZ Page

    I feel as though I need to clarify here. I am using a Silver and Copper alloy brazing rod - not Lead free Plumbing solder. I am connecting a #4 solid Copper wire to a Copper clad ground rod. Except for the small amount of Silver (15%) in the alloy it is a connection from Copper to Copper with Copper.

    If a lighting bolt is able to 'ZORCH' that connection then the ground wire is also going to be ZORCHED along with all the mechanical connectors (split bolts) too.

    I am certainly no expert in this field. But, based on experience and education, my belief system just has a hard time accepting that a mechanical connection is superior to a molecular bond.

    Dan KI4AX
    AC5RH likes this.
  10. KN4DQE

    KN4DQE Ham Member QRZ Page

    Why bother to do that when cadweld one shots are about $5 each and are much quicker? I used them for my grounding system and never looked back easiest method to bond copper together.
    N5HZR likes this.

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