> 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
> On 4/24/06, email@example.com <firstname.lastname@example.org> wrote:
>> Additional comments embedded below.
>> 73 de
>> Gene Smar AD3F
>> -------------- Original message ----------------------
>> From: "Kelly Taylor" <email@example.com>
>> > 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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