[TowerTalk] Info/Advice re: Exothermic Welds

[K8RI]

On 8/21/2012 5:21 PM, Dick Green WC1M wrote:
> The Erico website and their Cadweld catalog contain a wealth of information
> on their products:
>
> http://www.erico.com
>
> http://www.erico.com/public/library/fep/LT0355.pdf
>
> They even have a jig to prevent wires from moving.
>
> Until I looked through the catalog, I wasn't aware that they had molds for
> rebar. Had I known, I might have gone that route instead of using mechanical
> clamps on the rebar in my Ufer ground.
>
> I used many one-shot molds for grounding towers and my single-point ground
> with good success. Never had problems with molten metal leaking out of the
> molds, probably because I used very large gauge wire: stranded 1/0. Speaking
> of stranded wire, I think it's interesting that the conventional wisdom on
> this site is to use #2 solid conductor, while virtually all of the
> illustrations in the Erico catalog show stranded wire.

The industry has pretty well solved that for us. Try to find bare #2. 
The only way I could get it was to order a 500 foot roll.   I didn't 
even bother stating I use #2 "stranded" because I could not get solid.


>
> Out of dozens of connections, I had ignition failures on maybe two or three
> charges. They pack the igniter dust into the bottom of the charge capsule
> and you have to be careful when dumping the charge into the mold not to mix
> the charge and the igniter.

If you drop the cartridge the igniter will come loose and pour out with 
the regular charge.


You should slowly pour the charge into the mold,
> then lightly tap the capsule to deposit the igniter on top of the charge. A
> good bit of igniter has to be directly under the hole in the mold cap to
> capture a spark from the flint gun.

The "One Shot" I use have a funnel shaped cap with a hole in the bottom. 
  You tap the igniter charge into this from the top which makes it easy 
to ignite. Once it starts burning it drops through into the regular 
charge and you are off to the races.

<snip>

73

Roger (K8RI)