[TowerTalk] What Welder Makes Good Exothermic Bonds?

[Tony King - W4ZT]

The manual method equivalent to the Cadwelds or other name brand exothermic 
"one shot" welds is brazing or braze welding. You can braze with 
Oxy-Acetylene and Mapp.  The problem with the manual method is that unless 
you're well practiced, you'll melt away your ground wire since the 
temperature of melting the brazing rod is very near the melting point of 
the copper wire.  The exothermic "one shot" methods hold everything in 
alignment with a mold and raise the temperature above the melting point and 
hold it there until it cools.

Using an electric arc welding process isn't the proper way to bond these 
materials and the only one that might work bonding the non-ferrous copper 
to copper clad steel is TIG (Tungsten Inert Gas, now called Gas Tungsten 
Arc Welding, GTAW). I have TIG in my shop but would opt for brazing for 
grounding purposes or the simple one shot methods.

If you need to weld common mild steel in your shop you can't beat an 
inexpensive stick welder but don't buy it for making up your grounds. As 
Kevin pointed out, MIG (Metal Inert Gas, now called Gas Metal Arc Welding, 
GMAW, because it isn't always done with an inert gas) is the easiest but 
without instruction and much practice your welds will likely look pretty 
but wont hold up under stress because of the lack of penetration and 
fusion. Good penetration with MIG is all about technique.

If you have MAPP or Oxy-fuel already, get brazing rod, either coated or 
with a jar of flux and try it.  It's cheap. If you don't, just buy the 
Cadweld or other single shot brands and enjoy the beautiful ground connections.

73,
Tony W4ZT

At 09:19 AM 7/3/2004, Alan AB2OS wrote:
>So how well would brazing with a Bernzomatic or similar Propane or MAPP 
>torch work for bonding copper ground wires to copper-clad steel ground rods?
<snip>
At 08:41 AM 7/3/2004, Kevin wrote:
>All welders produce exothermic quality welds, in the hands of someone who 
>knows what they are doing.
>
>The welding process produces an alloy of the base metal and the weld metal.
>There are three main types of welders. ARC, MIG and TIG. Arc is what we 
>call "stick welding" and probably the most recognizable by regular folks 
>and the hardest to learn to do right. MIG is Metal-Inert-Gas and uses an 
>inert gas to shield the weld from oxygen till the process is finished. The 
>inert gas could be Argon or CO2. This process is commonly called "wire 
>welding" because the weld metal is a wire fed from a spool automatically 
>rather than a stick, and is the easiest for the common individual to 
>learn. The last is TIG and is specialized. I doubt seriously whether a lot 
>of people have TIG rigs in their garages or workshops.
<snip>