> I would like to start looking for a welder that may be used to make
> exothermic-quality welds.
It is difficult to weld metals of different melting points and conductivity
and end up with a good weld quality. Hence it is usually done using an
exothermic process instead of regular welding.
>
> What features should I look for in a an affordable occasional
> use device, please? (i.e. not a commercial duty-cycle)
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
>
> I will not only be using it for the house and tower-related
> grounding projects I will also be needing to do some repairs
As has already been mentioned there are the MIG and TIG welders.
I have MIG and use 0.030" wire with an Ar/CO2 mix for cover gas. Used
outdoors it requires either a very calm day or a *lot* of cover gas.
MIG welders are much like using a "stick" welder but without the mess from
the flux. They do require a good reliable wire feed and that is not always
present on the inexpensive models. OTOH you can get a fairly good one
without spending a fortune (relatively speaking). Wire with a flux core is
also available for welding in conditions where the cover gas just won't cut
it as in windy conditions.
Heat control as well as the speed at which you weld are very important.
With the proper heat and wire speed you can make a great weld, but just slow
down your moving the gun and you can almost instantly blow a hole right
through the metal. OTOH with a little practice you can learn to fill in
those holes as well. <:-))
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
feed in the rod just like brazing or torch welding. As with MIG welding you
need a nice calm day outside.
Of course there is still the plain old "stick" welder which uses flux coated
rods. A cheap "buzz box" and they work quite well on steel. I don't think
I'd try welding copper to steel with one, but I'll bet a certified welder
could do it.
Finally there is the "torch", Using Oxygen and Acetylene. You can get a
fairly nice set of Victor regulators and set of "tips" for probably on the
order of $150. Don't buy cheap. A set of tanks can be purchased or leased
and they come in a variety of sizes. "As I recall" the lease for full size
and one size smaller runs around $100 with refills running about $15 to $20
US.
With practice you can weld dissimilar metals using a torch, but I'd want to
be pretty proficient at welding regular metals before trying. With the
torch you have the option of Brazing and I see no reason why a good brazed
joint wouldn't work _IF_ the _surfaces_are_clean_and_shiny prior to making
the joint. You can weld Aluminum with a torch but it takes a lot of
practice and skill. New techniques make it easier and better than the old
way. I've seen outstanding welds done on aircraft skin that didn't even show
after working the metal.
> to my two trailers and my van and may then pass it on to a
> friend who is starting up a farm.
I believe you asked, in a later post, about the Bernzomatic torch and
brazing?
Using one with a welding type tip AND Map gas along with Oxygen it could be
done, but I doubt the regular Bernzomatic and air would give either enough
heat or control. You have to play the heat on the ground rod and copper
cable in such a manner as to bring both to the melting point of the brazing
rod. Without good control you are likely to melt the copper cable and get
the oxide on the ground rod making a good joint very difficult.
If given a choice of welders AND I planned on welding disimilar metals in
addition to regular base metals, I'd pick the TIG any day. The TIG is by
far the easiest to use when welding Aluminum. I've done it with the MIG,
but the heat, speed, and control of the gun are critical and take lots of
practice (and patience cleaning out "birds nests". If you've ever used a
bait casting reel you'll understand) I also find the TIG very easy to use,
but OTOH I'd not say it's a welder for beginners.
With both the MIG and TIG wear protective clothing. They may feel awkard but
a heavy set of leather welding gloves are worth the cost and they are
relatively inexpensive. Wear a hevy long sleeve shirt. You can get one
whale of a sun burn in a very short time. You can get a very bad sun burn
with a little more exposure. The new electronic helmets are very nice and
make the transition from looking in daylight to welding much easier than
looking, flipping the hood down, and then hope you still have the gun in the
right place.
Given a real choice I did choose a good MIG welder (Millermatic 185) and use
"One Shot" CadWeld (TM) cartridges for the ground system. I've gone through
two tanks of cover gas and three large spools of wire with the MIG. I'm on
my third refill on the Oxygen and Acetylene tanks. It's amazing at all the
welding and cutting projects I've discovered. <:-)) That's just in the last
3 years.
Now if the market hadn't tanked a couple years back I'd also have a good
Plasma Torch for cutting.
Good Luck,
Roger Halstead (K8RI, EN73 & ARRL Life Member)
N833R, World's Oldest Debonair (S# CD-2)
www.rogerhalstead.com
>
> Thanks! & 73, doc kd4e
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|