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Re: [TowerTalk] Power ground

Subject: Re: [TowerTalk] Power ground
From: Tony King - W4ZT <>
Date: Wed, 26 May 2004 22:09:11 -0400
List-post: <>
I agree with Roger. Brazed joints in copper are actually called braze welding because the heat required to flow the rod (typically a copper zinc alloy looking like brass but a different mix with a melting point between 1630F and 1650F) is near the melting temperature of the copper at 1981F. In the welding world, any process done above 800F is either brazing or welding but never soldering. The problems with joints in copper pipe systems used for grounding are commonly soldered joints and those are less desirable. Exothermic welds create the same kind of joint as you would create while brazing though in a quicker simpler form. Though some of us are equipped to braze and weld, many folks aren't. The exothermic welding devices (by any name) are much easier to keep and use and the resulting connection will always "LOOK" better because of the mold but electrically they can be identical to brazing.

From my post here on 10/21/2003:
"If you look at MIL-HDBK-419A, Grounding, Bonding, and Shielding for Electronic Equipments and Facilities, (available as the complete 2 volume set at but a large file around 9.7 mb) you'll find that brazing and exothermic bonding are the two recommended methods (by the military) for joining components in a grounding system. Brazing requires higher temperatures than soldering so you would use oxy-acetylene or mapp gas, brazing flux, filler rod (brass, brass alloy or silver alloy are common) and technique but it is far superior to solder in both strength and conductivity when used in similar materials (copper/bronze/brass etc). Brazing can be done easily with a little practice but care must be taken that the filler material flows into the joint, not just lays on top of it."

Tony W4ZT

At 01:57 PM 5/26/2004, you wrote:
I've been following this for a while and keep seeing reference to "brazed"
water pipes.
I've never seen a brazed joint in water pipes. Soldered, but never brazed.

The temperature for brazing is much higher than soldering and would be
enough to show some serious oxidation on the copper.  Brazing would require
the copper to be at a "cherry red" heat to get the stuff to melt.  In most
homes the amount of heat required would cause charring on any wood near the

It may not be permitted, but I'd trust a good brazed joint any day over a
compression fitting that can corrode.  I've had compression fittings
completely lose contact with ground rods.

Roger Halstead (K8RI, EN73 & ARRL Life Member) N833R, World's Oldest Debonair (S# CD-2)

> In a message dated 5/26/04 10:17:54 AM Pacific Daylight Time, > writes: > > > However using > > brazed water pipes is not recommended. The brazed connections represent a > > seriously weak electrical joint and may fail prematurely under thermal > > stress of high currents. > > Yessireebob. The only NEC ground connections allowed are compression and > exothermic (i.e. Cadweld). > > Cheers, > Steve K7LXC > TOWER TECH - > Professional tower services for commercial and amateur > 888-833-3104


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