In part 1 of this project, we scavenged some parts from household appliances, and modified
them so we could weld metal. In this project, we'll be rigging up the electrical system,
and adding some finishing touches so that our homemade stick welder is ready for operation.
I started this project with a scrap piece of 3/4" plywood that I had left over from
the "router table" project. And since we have a router table, let's profile the edges with
a beading bit, just because we can. Next, let's cut a piece of 2x2, and screw it in
from the bottom so that it's secured in the center, and about 1" from the edge. We'll
also need to drill a couple of pilot holes in the top, because this is where we'll be
attaching some copper lugs. To make these, we simply take a piece of 1/2" copper tubing,
and use a hacksaw to cut 2" from the end. Half of the tube can be placed in the jaws
of a bench vise, and when the vise is closed with a significant amount of force, you can
see that we're left with a nice flat end. Let's place that on another piece of scrap
wood, and drill a 5/32" hole so that it penetrates through to the other side. I've done this
with 4 different pieces, and to clean up the rough metal barbs, I'm using a belt sander
to gently file away at the edges until it looks a little more user friendly. This lug
here is gonna attach to a 5' length of 8 gauge cable. This was left over from when
we wound our coils. We'll just need to strip about 2 inches of insulation from the ends
to expose the copper wire, then bend the wire over with a pair of pliers to form a little
loop. The exposed copper loop can be slid inside the casing, and to make this a permanent
connection, let's crimp it onto the cable using the bench vise like we did before. This
connection isn't coming apart, and should easily handle the high currents that we'll
be exposing it to. The other end of this cable will be our ground clamp. I got this metal
clamp for $0.99 and with the rubber tips removed, it'll conduct electricity. I crimped a pice
of copper tube to the end of the wire, and secured it to the clamp with a screw. The
spring in the clamp is surprisingly powerful. It bites down with a good amount of pressure,
and that's what we need for making a firm connection with our workpiece. Now a welding
rod could just be pinched to the cable with a pair of pliers, but i went ahead and spent
$13 on a proper electrode holder. This makes it look more like a real welder, and adds
a tremendous amount of convenience and control. Ok, we've got our lugs crimped on the ends
of the secondary coils, so let's mount the transformers on the base. You probably noticed
that I cut the cable in the middle, and crimped them to a common lug in the center. This is
because I wanted an option to center tap the transformers to power other devices, like
an electrical arc furnace. Look for how to make that in a different project. A few screws
can be used to hold the transformers in place, and the grounding clip can be connected by
overlapping the respective lugs and pinning them down with a screw. The electrode holder
gets attached in the same way, and here you can see there is plenty of separation to prevent
the terminals from shorting out. Alright, let's get ready to rig up the electrical system.
This cord was saved from one of the microwaves we tore apart, and after exposing the 3 wires
inside, I'm gonna cut off the green one just to get it out of the way. It's not gonna
to be connected to anything. Now here is the trick to powering the welder. 240 volts AC.
I can't recommend this is the safest way to do it, but here's how I did it with a couple
of plugs, a connector, and some 10 gauge wire. Each outlet in my house provides around 120
volts AC and they're connected to a circuit breaker bus bar. There are 2 breaker busses,
and if a hot lead is taken from each of the busses, we get 240 volts. Now rather than tapping
into the breaker box directly, I ran extension cords to 2 different wall outlets that were
180º out of phase. The extension cords connect to this adaptor, which basically just connects
the 2 hot leads together. If connected properly, the end result is 240 volts. Looking at the
back of the transformers, you can see 4 terminals that connect to the primary coils. I used
some salvaged cables and wire nuts to connect a hot lead to one transformer, and a hot lead
to the other. Another wire was used to bridge the two, connecting them in series. By the
way, the color of these wires doesn't mean anything. They're all gonna be shock hazards.
Ok, to finish up, let's fasten the power cable to the base so it doesn't pull the connections
apart if the cable gets jerked around. It's extremely important to remember this system
has no on or off switch, and can only be used with a power controller, like the Scariac.
You can see how to build this in another video. If you remember back to when we inserted our
new secondary coils, I mentioned it didn't really matter which way they went in, and
here's why. When the power is on, and our welding electrodes are connected to a multimeter,
we should expect to see around 36 volts. But here we're only getting 2.4. That means the
transformers are canceling each other out. To fix this problem, let's just turn off the
power, and remove the connections to one of the transformers. It shouldn't really matter
which one. Then we simply, switch the connections around. That's it. This time when we turn
on the power and check the voltage, we've got 37 volts. Now, rather than leaving all
the dangerous components exposed, I think we can build a make-shift casing from this
plastic container. Here are the exact measurements if you care to know. I choose to use the lid
as the base, and used a rotary tool with a cutting wheel to make the surface flat. Our
entire welding assembly should fit right in the center without any problems. I gave the
whole container a paint job, set the bin into position, and locked it into place. Two holes
went in the front for our electrode cables, and I also cut some ventilation holes on the
sides. There's a hole in the back for the power cable, and now our welder is completely
finished and ready to test! Let's start by directly shorting out the ground clip with
the electrode holder, because this will allow the maximum amount of current to flow. We'll
use an amp meter to monitor the primary current, turn on the Scariac, and power up. When the
power settles at around 15.5 amps on the primary, you can see it produces about 100 amps on
the secondary. The amperage is adjustable, so if we add more power, we can jump the welding
cables to over 200 amps. In any case, there's certainly enough power available to strike
an arc, sustain it, and weld some metal. You can see some of my first few experiences,
with the world of welding, in another video. Well that's it for now. If you liked this
project, perhaps you'll like some of my others. Check them out at www.thekingofrandom.com