Nice pics, Roger.
I've never packed my one-shots, but wish I had thought to do that. I've had
molten material run out of a couple of them. Then again, I've done a couple
of dozen of them without packing and didn't have any material run out. I
used 1/0 wire, which fits pretty tightly in the metal fittings, and found
that it's important to keep the mold level. Also, in most cases I didn't cut
the wire. Instead, I slipped the mold on at the free end of the wire and
slid it to the ground rod. That way, no worries about the wires being butted
together close enough.
However, with the old ceramic molds, sliding the mold sometimes causes one
or both of the metal fittings to work loose from the mold. Not a big deal,
the two fittings and mold can be slid along the wire as long as you're
careful not to damage the mold. It's much trickier with the newer styrofoam
molds. They're quite delicate and you have to be extra careful not to damage
them. I generally had to remove both metal fittings when sliding the mold.
Pictures of my recent adventures with one-shots are on my website at
www.wc1m.com. Click on "Ground System" in the bar at the left.
73, Dick WC1M
> -----Original Message-----
> From: Roger (K8RI) [mailto:K8RI-on-TowerTalk@tm.net]
> Sent: Sunday, June 17, 2007 11:00 PM
> To: Gene Smar; K4SAV; towertalk@contesting.com
> Subject: Re: [TowerTalk] Cadwelding and grounding nightmare
>
>
>
>
> > Peter:
> >
> > Jerry speaks the truth. A rented trencher, like a Ditchwitch,
> would
> > make short work of your trenching project. I dug trenches for my
> > grounding
> > wires and for my conduit system in one day with a rental.
> >
>
> When I put in a ground system like this I only put the cables about 3
> to 6
> inches down so I don't need any trencher although after slitting a few
> hundred feet of sod in clay one begins to sound pretty good.
>
>
> > Jerry is also correct in suggesting that the molten shot is
> running
> > out
> > of the holes in the (I assume) One-shot Cadweld molds. I had the
> same
>
> After reading the post I though he was talking about using the graphite
> mold
> and measured shots.
>
> If he is using "one shots" it's a given the molten charge is running
> out,
> but the ceramic should be "banked" thouroughly in dry sand (all the way
> around and underneath.) If the charge is burning off the cable there
> are
> several possibilities in addition to not properly banking the mold.
> Wires
> too small or an over size mold holding to large a charge. Also the
> wires
> must butt together tightly "on top" and in contact with the ground
> rod.
> The wire should be bare and solid, but coarse stranded will work. The
> wire/cable should be of such size it just nicely fits through the metal
> thimbles in the sides of the mold.
>
> If he's using the graphite mold then there is the possibility the
> charges
> may be too large.
> "One shots" are far easier to use.
>
> I would add that even the "one shots" develop enough heat and light to
> be
> dangerous and the proper igniter should be used. Looking directly at
> one
> when it's fired is as dangerous as looking directly at the sun wihout
> protection. They are hot enough to burn through concrete. That stuff
> will
> go through steel plate like butter.
>
> > problem with the first one I tried. After I cut off the half-welded
> top
> > of
> > the ground rod and fixed a second ceramic mold on top of it, I sealed
> the
> > holes for the side wires and around the rod itself, underneath the
> mold,
> > with electrician's putty (available at Home Despot, Lowe's, etc.) I
> did
> > twelve welds successfully thereafter.
>
> I just thouroughly pack/bank them with sand right up flush with the
> top, but
> what ever method, they have to be completely contained.
> http://www.rogerhalstead.com/ham_files/ground.htm The photos near the
> bottom show how I bank them.
> I now use a NEMA box and grounding bulkhead at the entrance to the
> house
> instead of the fixture shown with the Polyphasers at the bottom of the
> page,
> but I've not had the chance to update the page.
>
> Roger (K8RI)
>
>
>
>
> >
> > Good luck with the project.
> >
> >
> > 73 de
> > Gene Smar AD3F
> >
> >
> > ----- Original Message -----
> > From: "K4SAV" <RadioIR@charter.net>
> > To: <towertalk@contesting.com>
> > Sent: Sunday, June 17, 2007 5:35 PM
> > Subject: Re: [TowerTalk] Cadwelding and grounding nightmare
> >
> >
> >> Sounds like the molten metal is running out the holes around the
> wires
> >> or around the ground rod if it doesn't fit tightly. You can pack it
> >> with sand to prevent this. The trenching can be difficult if the
> >> digging is done manually. Renting a trencher can make it much
> simpler.
> >> Putting in the ground rods is the most difficult part. You said you
> >> have already done this? That does make the trenching a little
> harder,
> >> avoiding the ground rods then manually digging out around them.
> >>
> >> Jerry
> >>
> >> Peter Dougherty wrote:
> >>
> >>>Hi all,
> >>>
> >>>This is a desperate plea for help from Northern NJ. I need to get a
> >>>major cadweld-grounding project completed, and as events of this
> >>>weekend have proven, this is not a task neither I nor my xyl are
> >>>physically capable of performing. It almost ended up with me in the
> >>>hospital and my wife ready to take off permanently. I am NOT joking
> >>>about this, either. Yes, the fight was THAT bad. It's just the two
> of
> >>>us here. I'm in bad condition physically and can't be outside in
> heat
> >>>for more than an hour or so, and she can only do so much to help.
> >>>
> >>>I have the ground rods down and mapped out but trenching out where
> >>>the wires are supposed to run and properly firing off the cadweld
> >>>shots turned out to be a massive and expensive waste of time, effort
> >>>and money. The last straw was the shot I fired off. Made a nice 3"
> >>>flame and a couple of minutes of glowing orange, but when the smoke
> >>>cleared and things cooled down out popped one of the wires from the
> >>>mold as if it was never even effected.
> >>>
> >>>If there's anybody who is expert at this process and willing to come
> >>>to northern NJ please contact me at your earliest convenience. Guys,
> >>>I'm in waaaaaaaay over my head on this one. I bit off way more than
> I
> >>>can chew and I need a pro and some folks with experience to get this
> >>>done right.
> >>>
> >>>
> >>>
> >>>Thanks in advance.
> >>>
> >>>Peter,
> >>>W2IRT
> >>>
> >>>_______________________________________________
> >>>
> >>>
> >>>
> >>>_______________________________________________
> >>>TowerTalk mailing list
> >>>TowerTalk@contesting.com
> >>>http://lists.contesting.com/mailman/listinfo/towertalk
> >>>
> >>>
> >>>
> >>
> >> _______________________________________________
> >>
> >>
> >>
> >> _______________________________________________
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> >
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> >
> >
> >
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