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Default Home Brew Spot Welder

Spotwelders can actually be pretty simple. An appropriate transformer,
timing device, relay to control transformer primary supply, and mechanical
clamping of the tips are what are required. We have several shop built
spotwelders at work to weld smaller parts. I have a 15 KVA commercial unit
at home. To weld sheet metal body parts, I think you'll need transformer
ratings of about 5 to 15 KVA. The electrical expert types will have to be
the ones to determine this. I use 15 KVA units to weld 1/16" steel tubings
telescoped together on a setting of 3 of an available 5 on the range
selector of a factory built unit. Water cooled tips are used for production
work. A capacitive discharge unit is what I use to spotweld brass to bronze,
and brass to stainless. Spotwelding basically is a process of mechanical
clamping pressure at the tips, electrical power applied through the tips,
holding time for this power, then release of clamping. All of these
variables are adjusted for weld quality of the "nugget". Special coppers are
required, and tip diameter is important. A company called New Southern
Resistance Welding is where I get my basic supplies. Miller makes a handheld
unit for body panels. Maybe you could copy it's design. Hope this helps you
a little.

RJ

--
"You're just jealous because the voices are talking to me, instead of you."


"Howard Eisenhauer" wrote in message
...
Anybody here ever built your own spot welder? I've got some major
re-assembly work coming up on my jeep tub & I've been thinking it
might be easier/faster to do real spot welds instead of the "drill
hole/mig weld plug/grind down" route. I've found a few references on
google to plans for units using re-wound microwave oven transformers,
intended for use on small projects such as model gas turbines, but
there isn't enough detail to convince me they'd work on heavier sheet
metal.

So, if you have any experience with something like this or know of any
on-line resources that google (Gasp!) doesn't know about I'd
appreaciate hearing from you.

Thanks,

Howard.