[TowerTalk] What Welder Makes Good Exothermic Bonds?

[Tower (K8RI)]

> > If you are talking ground rods, it's by far cheaper (and easier) to just
> > purchase a few "one shot" cartidges. Everything comes premeasured.  You
just
> > fit the form around the rod, put the ground wire in the opening(s)
provided,
> > pack dirt around the form, pour in the charge, put on the top, add the
> > igniter charge,  and touch it off with an igniter.
> > http://www.rogerhalstead.com/ham_files/ground.htm
>
> It would appear that I am looking at 12-15 ground rod welds, plus maybe
> some rebar welds, that's a lot of disposable "one shots"!  ;-)

I now have some where around 33. I lost track. <:-))  Purchasing them by the
carton they are roughtly $10 each.  There are 12 per carton and of course
the price break comes at 13. IF they have to order them they are available
only by the carton, at least around here.

Of course $200 worth of one shots is a lot less than a $900 welder, let
alone a $4000 welder.
Then, unless you are already a welder, you have to learn how to use the darn
thing.

Then again you are *almost* guaranteed a good weld if you follow directions
with the one shots.  They are fast and contain just the proper amount of
filler and give a joint that would take either a lot of skill or luck to
match with other forms of welding.

There is also the carbon block/form and purchasing the charge in bulk.  As I
recall the break even point was around 12 to 15 welds.  I would have saved
money by going that route, but I didn't want to mess with the carbon block,
or keeping that much thermite in my shop.
>
> >>I will not only be using it for the house and tower-related
>
> > I would add that using a TIG welder is very much like using an
OxyAcetylene
> > torch, but the heat is supplied by an arc. The arc supplies the heat and
you

I should have noted It's also more concentrated.

> > feed in the rod just like brazing or torch welding.  As with MIG welding
you
> > need a nice calm day outside.
>
> So far I am seeing TIG welders for $900. - $4,000!  Out of my range
> for sure!  Perhaps something used/refurbished?
>
> I have yet to find any reference to copper and references to
> only certain models sufficient for aluminum.  Hmmm.

They may not reference it, but any TIG welder that has the heat capacity
should work on coper and aluminum.  You'd probably need to use a different
cover gas though.
>
There are several problems using an arc on Aluminum and copper. As I recall
the big difference is between the voltage necessary to establish the arc and
that required to carry the current to melt the metal.  It takes a *lot* of
heat (BTUs) to melt Copper and Aluminum copared to steel even though steel
has a much higher melting point..That is one of the things that raises the
price.

Also "to me" TIG welding is much more of an art than MIG, or stick welding
and a class on welding would be a good idea.It usually takes most people
quite a few hours before they can run a good horizontal bead/weld joining
two flat plates with any type of welding.

I still think your best bet for the ground rods is the one shot approach
followed by OxyAcetylene.  Bernzomatic does make a OxyAcetylene and
OxyMapgas torch with tanks the same size as the butane tanks.  I think the
tanks run on the order of $10 to $12.  One tank of Acetylene would probably
get you through ... guessing... maybe 6 or so ground rods. I'm not sure how
far the Oxygen would go.  They are limited to using a relatively low
pressure which means the tanks will probably not last long.

To braze the copper cable to a ground rod I'd get a good thick coat of
brasing rod melted to the top of the rod and then using lots of flux work up
through the copper cable, or thouroughly coat the copper with brazing rod
and then bond the two together.  That might be easier.You do have to be
careful as the melting point of coper is close to that of the brazing rod,
but it can be done.  With experience the copper could be brazed to the
ground rod with a secure and good looking joint.  Unfortunately experience
costs money and lots of time, at least for most of us   <:-))  To top it
off, mistakes can be expensive.

> Guess I need to keep learning and searching

We all do. I was counting on that 290 million lottery for my new floor mill
and lathe <:-))  Maybe I should buy tickes next time to increase my
chances... slightly?
.
>
You *might* find a reconditioned TIG, but the ones I've seen were all
industrial size units and still expensive.  My neighbor is a rep for one of
the local industrial suppliers which does help a bit <:-))

Roger Halstead (K8RI, EN73 & ARRL Life Member)
N833R, World's Oldest Debonair (S# CD-2)
www.rogerhalstead.com
> 73, doc kd4e
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