[TowerTalk] Tower Grounding Questions

[Jim Lux]

On 12/21/11 8:00 AM, Richard Solomon wrote:
> A friend is putting up an LM-470 and asked about grounding it. Who
> makes the Ground Kit for
> the tower ? I have a couple of DX Engineering PPC-UNI-KIT-2CT kits,
> will they do ?
>
> Also, what's the name of those one-shot chemical "bombs" used to weld
> the ground cable to
> the ground rod ?

Exothermic Welding, generically..

Erico Cad-Weld is a very popular brand (OneShot is one of their models)
Thermoweld is another
UniShot is another

If you go to a electrical supply place, they'll carry one or more 
brands.  They'll also have the stuff you need to use it (some kinds have 
a reusable mold and you load the charge in each time from a little 
container).  There are fancy igniters and such, as well.  Do some 
research (there's been stuff on this list over the years). I've used a 
small torch to light them off, but I'm not sure that's actually recommended.

I've never seen this stuff at Home Depot or Lowes.. at least at the ones 
I go to, but that doesn't mean that some don't carry them.  You need to 
go to somewhere that really caters to "trade".

You *could* make the stuff yourself, in the fine ham radio improvising 
way. It's just thermite...  Copper oxide and aluminum powder, piece of 
magnesium ribbon as fuse works nicely.

What you are paying for with the commercial product is a nicely designed 
mold and consistent mixing of the weld material. The commercial ones 
also have a different mix at the ignition point to make it easier to 
start (I'm going to guess some sort of black powder type mix.. a good 
oxidizer and some fuel which gets good and hot, to get the metal 
oxide-aluminum reaction going).