[TowerTalk] Ground rod connection: Cadweld or ????

[K8RI on Tower talk]

> When I talked to Joel at The RF Connection about Cadweld one shots
> about 2 months ago he told me that the "old style" one shots has been
> discontinued and replaced with a "new style" which needs to be ignited

The old ones had two powder mixes. The main charge was loose and just poured 
in.  The igniter was a fine powder that would stay in the bottom of the vial 
until you tapped it out.  That stuff you could light with a kitchen match 
(not a good idea).  I don't know if they did away with that or not.  I had 
the igniter powder fall out with the charge on a couple that had been 
dropped and those cases just used a small torch to ignite the main charge.

> with a very expensive igniter from Cadweld (like $150 or $250 or
> something like that).  I don't know if this has changed, but ...
> that's going to stop a lot of hams from going the Cadweld route if
> something isn't done about it.

Where there's a will there's a way. <:-))

Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
>
>
> On 4/24/06, ersmar at comcast.net <ersmar at comcast.net> wrote:
>> TT:
>>
>>     Additional comments embedded below.
>>
>> 73 de
>> Gene Smar  AD3F
>>
>>
>>  -------------- Original message ----------------------
>> From: "Kelly Taylor" <ve4xt at mts.net>
>> > Hi Bob,
>> >
>> > Cadwelding, once you know some of the tricks, is dead simple.
>> >
>> > Key things to remember are:
>> >
>> > 1. Matches or other simple flames will not ignite the material. It's
>> > deliberately designed such so that the material is less volatile for
>> > shipping and storage. The sparker RFC sells is designed to cast sparks
>> > forward, as opposed to down, such as with a propane torch spark 
>> > ignitor.
>>
>> Available from RFC for less than $8.
>>
>> >
>> > 2. Grind/cut off mushrooming: when the thing says it fits 5/8-inch rod,
>> > that's ALL it fits. The bits spread out by pounding the rod will 
>> > prevent the
>> > form from sliding on.
>>
>> To protect the tops of my ground rods from mushrooming, I constructed my 
>> own drive sleeve out of four inches or so of 1 inch iron pipe and a pipe 
>> cap.  I put this thing over the ground rod and pounded the ---- out of it 
>> with almost no damage to the top of the rod.  I needed two of these 
>> sleeves for twelve ground rods.  (I put a piece of electrical tape around 
>> the rod where it protruded out of the sleeve to protect the copper 
>> cladding from damage from the bottom of the sleeve while pounding.)
>>
>> >
>> > 3. Secure the wires from movement: the combustion process can exert 
>> > some
>> > force on the wire, causing it to be ejected from the form. End result,
>> > useless weld. Doesn't need to be much: a brick a foot or so away from 
>> > the
>> > form preventing the wire from moving is all it would need. The force is
>> > enough a free wire can be cast out, but not so big as to bend the wire.
>>
>> My first Cadweld attempt failed because the molten shot leaked out the 
>> bottom of the ceramic mold.  I cut off the bad weld and tried again, this 
>> time sealing the bottom and side openings with electrician's putty (Home 
>> Despot).  Never had a failure in the remaining welds.
>>
>> >
>> > 4. The risk, if there is any, is similar to lighting a barbecue. Don't 
>> > put
>> > your head over the form and you'll be fine. It's not like you're 
>> > lighting
>> > fireworks and need to retreat quickly. The ones I did had maybe 3 
>> > inches of
>> > flame, and it took a second or two to build to that anyway.
>>
>> But it IS smokey!  Stay upwind of the shot while you ignite it.  (Very 
>> disappointing that there was so little noise and flame.)
>>
>> >
>> > 5. Expensive? About $8, as I recall. A ground clamp is about $3, no? So 
>> > for
>> > an extra $5 you get a maintenance-free connection for life. Not a bad 
>> > deal.
>>
>> My ground system (rods, wire, Cadwelds, tower leg clamps, etc.) cost me 
>> about $500.  The extra $5X12=$60 for the Cadwelds was a small price to 
>> pay for reliable, trouble-free ground connections.
>>
>>
>> >
>> > 73, kelly
>> > ve4xt
>> >
>> >
>> _______________________________________________
>>
>>
>>
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