Make a Spot Welder for Cheap!!


A typical resistance spot welder like this
can range in price from around $200 to over $800! That’s a little out of my price range,
so for this project let’s make this one from common materials, and for just a few bucks! This modified transformer is the heart of
the Spot Welder, and you might remember it as the “Metal Melter”. If this doesn’t look
familiar, check out how this was made, and what it can do, in some of my other videos.
I found a practical application for it in making a spot welder like this one. To get
started, I’m going to measure the base of the transformer, and it looks like it’s about
4-1/4″ wide. I found a 6′ piece of 1×6″ common board that will be perfect for this. Using
my chop saw, I’ll cut two pieces of the board so that they’re both 12″ long, then another
piece gets cut at 42″. I’m trimming this piece down with my table saw, so that it’s about
1/4″ wider than the transformer base, and in this case that measures out at 4-1/2″.
Then it gets chopped into 3 different lengths measuring 24″, 12″, and 4″. Next, I found
a 2×2 and am cutting the nicest parts of the beam into two pieces measuring 13-1/2″ long.
2 other pieces are cut at 4″ and everything can be placed together to see how it fits.
That’s the rough idea right there, and I’d like to knock down the sharp edges, so I’ve
found a 3/4″ rounding bit and routed the appropriate edges to give it a smoother feel. These front
pieces are going to be my electrode holders. The edge of this scrap piece of wood works
as a template to draw a 90º angle into the top piece about an inch from the end. I don’t
have a bandsaw, so I’m improvising with my bench vise and a jigsaw to cut this piece
out, and it worked. You’ll see what this groove is for in a bit. The next part is to cut out
the pattern I drew onto the back panel, so I’m going to utilize my vise once again, and
use an 11/32 drill bit to cut holes in all the corners so I can get back in there with
my jigsaw. These holes will be for a switch and a power cord, and all this panel needs
now are two pilot holes drilled in the appropriate places for the switch. I’m thinking I should
give this a paint job, so all the panels get sanded with an orbital sander, then laid out
for priming and painting. I’m thinking black and yellow. With the paint drying, I’ve gathered
up a few components that were saved from the same microwave I got the transformer from.
To see all the amazing things I got from that project, make sure you check out my video
on salvaging a microwave I found in my neighbors trashcan. I’m going to use the power cord,
these wired spade connectors, the door handle, and this contact switch. Aside from the wood,
the only parts I needed to buy were a single-pole light switch, with matching cover, copper
offset terminal lugs, a couple of 1/4 thick screws, 2 small nails and a length of 6 gauge
solid copper wire. The copper wire gets marked off in 1″ increments, and two pieces are cut
off using the wire cutter on my pliers. These are going to work as my welding tips. The
copper lugs have an adjustable screw that can be loosened to insert the solid copper
wire. When it’s tightened back up it looks like this. Alright the paint on the wood panels
is dry, and I’ve added the switch to the back panel to make sure it fits, so the next step
is to flip it over and press the power cord down into the hole at the bottom. The thick
piece at the end of the cord prevents it from pulling back through the hole. I’m ready to
piece this back together, so I’m drilling a couple of pilot holes into the bottom, and
securing the back panel with a couple of screws. Now the front 2×2 supports are added and the
Metal Melter is placed on the base about an inch back from the supports. I’ll add a screw
to one of the corners to help keep it in place, and at this point I’m ready to rig up the
electrical system. Taking the green wire from the power cord, I’m stripping open a gap in
the plastic to expose the bare cord. This will wrap around the grounding screw on the
power switch. The end of the wire has a hole I can use to insert another short screw, and
work that down into the opposite corner of the transformer base. Not only does this secure
the Metal Melter in place, it also grounds out the transformer core at the same time.
Ok, I’ve exposed the copper on the black wire, and that will get connected to the bottom
terminal of the power switch and screwed down tight. This salvaged spade connector still
fits onto one of the transformers primary terminals, so with that on, the other end
of the wire can be connected to the top terminal of the power switch. Now the switch can be
screwed down permanently, and a cover plate added to protect from electric shock and make
it look nice. The other spade connector that was salvaged goes on the left terminal of
the primary coil, and we could finish the electrical here, but I want to add one more
switch, for convenience. This switch still has the original wires and connectors from
the microwave, and I’ve just added a wrap of electrical tape to make sure I don’t get
shocked while touching it. I’ll strip the end of the white wire, and twist it together
with the other white wire coming off the primary, then use a wire nut to cover the connection.
Now the black wire is joined with the white wire coming from the power cable, and the
electrical system is complete. I added this microwave door handle to the top panel and
am screwing it on to see how it holds up. The alignment looks good, and when I pick
it up it seems to support the weight without any problem. Alright, with the cables laying
out the front, it’s time to close up the side panels, and I’m doing that by drilling holes
and adding six screws on each panel, to make sure it’s held securely. The next step is
to construct these electrode holders. I chose to use a 3/16th bit to drill a hole into both
tips of the 2×2’s, which you can see got painted yellow. The hole is big enough to prevent
the wood from splitting when these screws go in, yet small enough to hold them secure.
This is the top piece and I’m going to add the switch to the side, about 1/2″ from the
tip. It gets set at a slight angle and the two small nails are hammered down into the
holes already in the switch. Now the 2 beams can be slid into the front of the casing,
with one under the wire, and the other overtop. To secure them in place, I’m using some scrap
wood to keep them an equal distance apart as I drill a hole through the side of the
casing, and into the beam. I’ve pushed a nail into the hole, and now you can see this top
piece is able to pivot freely. It should be obvious now why we needed that notch near
the base. The bottom beam also gets a hole drilled on either side, as well as it’s own
set of nails to keep it from sliding around. The welding tips can be attached now, so we
push one of the hex screws through the hole in the lug, and then join it to the right
side cable. That gets tightened securely into our pilot hole, and all that gets repeated
on the top. The misalignments can be fixed by bending the lugs slightly inward, and now
we’ve got perfect contact. To finish this off, I’d like a way for the top beam to stay
suspended on it’s own. So to address the challenge, I’ll add a couple of screws and a thick rubber
band. This system is finished! My very own spot welder, and for less than $10 in materials.
Let’s see if it works. Power cord plugs in, and with the electrode tips touching, I’ll
press the button to engage. But nothing’s happening. That’s because the safety switch
is still off. Let’s try it again. This time when I press the button, the system hums,
and when the tips touch, I see the high-amp sparks I was hoping for. I don’t have any
sheet metal handy, so I decided to try using these washers for my first experiment. The
pressure holds them I’m place hands free, and with the system energized, it only takes
about 3 seconds to fuse them together. I’m trying it again with a third washer, being
careful not to touch these, because they’re extremely hot. Surprisingly, it even worked
on thicker welds like melting a washer to this steel spike. Trying to break them apart
by hand was a fruitless effort, so I tried using pliers and even that was a bit of a
challenge, but I got it. That just goes to show the welds are pretty strong. A feature
I really like about this design, is that the electrode holders can be removed, allowing
the user to extend the welders reach, and access difficult angles. They go back in as
easily as they came out, and all it takes to secure them back in place is a little wiggle
and the replacement of the locking nails. The elastic band is easy to replace, and is
doing a great job providing back tension after I make a connection. I tried welding a couple
of iron nails in an “X” pattern, and since the heat was concentrated in the center, it
didn’t burn my fingers. The power of the Metal Melter is still evident in the way the iron
is boiling on this nail, and if allowed to continue, the nail melts down into a little
ball of liquid metal. When it’s time to replace the electrode tips, just loosen the tensioner,
remove the spent electrode, and replace with a fresh piece of your copper wire. If you
do it this way, you can get 12 tips for a buck! Because the wires not that expensive.
Well now you know how to make my version of a spot welder from easily accessible, and
low-cost parts. If you liked this project, perhaps you’ll like some of my others. Check
them out at www.thekingofrandom.com.

100 thoughts on “Make a Spot Welder for Cheap!!

  1. He made life easy for us. Still helping after gone. This man will always be missed and no one will replace him.

  2. what's really getting to me is there was like 3 other deaths that were really close to me that happened this month, not to meantion the 3 shootings that popped up in my feed

  3. This man had me up at 2 am on school nights just because I wanted to see how to do these things and learn. You will be missed by many Rest In Peace you were an inspiration to a lot of people 😢

  4. He will be missed

    BUT HE WILL NEVER BE FORGOTTEN
    I honestly hope YouTube puts something about him in the 2019 rewind

  5. Rip in peace in peace
    F in the chat activated
    Press F on you keyboard in
    3…
    2…
    1…
    Now
    F activated
    TKOR is missed
    Dequip Hat
    Engage Cry
    Funeral initiated
    Equip Black Clothing
    Rain activated
    Equip Black umbrella
    Sadness forfilled
    Rip The King Of Random
    You will be missed.

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